AEE


Line plots across dimensions of each concept
Tables

Table of contents



us-gaap:CommonStockSharesOutstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:RevenueFromContractWithCustomerIncludingAssessedTax
us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity
us-gaap:Revenues
us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:SubsequentEventType, dei:LegalEntity

us-gaap:OperatingExpenses
dei:LegalEntity

us-gaap:OperatingIncomeLoss
dei:LegalEntity

us-gaap:InterestExpense
dei:LegalEntity

us-gaap:OtherNonoperatingIncomeExpense
dei:LegalEntity

us-gaap:IncomeTaxExpenseBenefit
dei:LegalEntity
us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity

us-gaap:ProfitLoss
dei:LegalEntity
us-gaap:StatementEquityComponents, dei:LegalEntity

us-gaap:ComprehensiveIncomeNetOfTax

us-gaap:ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest

us-gaap:ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest
dei:LegalEntity
us-gaap:NetIncomeLoss
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments, dei:LegalEntity
us-gaap:LitigationCase
us-gaap:LitigationCase, dei:LegalEntity

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic
us-gaap:StatementEquityComponents

us-gaap:NetIncomeLossAttributableToNoncontrollingInterest
us-gaap:StatementEquityComponents

us-gaap:Assets
dei:LegalEntity

us-gaap:LiabilitiesAndStockholdersEquity
dei:LegalEntity

us-gaap:StockholdersEquity
dei:LegalEntity
us-gaap:StatementEquityComponents

us-gaap:AssetsCurrent
dei:LegalEntity

us-gaap:CashAndCashEquivalentsAtCarryingValue
dei:LegalEntity

us-gaap:AccountsReceivableNetCurrent
dei:LegalEntity

us-gaap:InventoryNet
dei:LegalEntity

us-gaap:OtherAssetsCurrent
dei:LegalEntity

us-gaap:PropertyPlantAndEquipmentNet
dei:LegalEntity

us-gaap:Goodwill

us-gaap:OtherAssetsNoncurrent
dei:LegalEntity

us-gaap:LiabilitiesCurrent
dei:LegalEntity

us-gaap:LongTermDebtCurrent
dei:LegalEntity

us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent
dei:LegalEntity
dei:LegalEntity
us-gaap:TaxesPayableCurrent

us-gaap:OtherLiabilitiesCurrent
dei:LegalEntity
us-gaap:BalanceSheetLocation
us-gaap:BalanceSheetLocation, dei:LegalEntity

us-gaap:LongTermDebtNoncurrent
dei:LegalEntity

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent
dei:LegalEntity

us-gaap:MinorityInterest

us-gaap:OtherLiabilitiesNoncurrent
dei:LegalEntity

us-gaap:StockholdersEquity
dei:LegalEntity
us-gaap:StatementEquityComponents

us-gaap:RetainedEarningsAccumulatedDeficit
dei:LegalEntity

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax

us-gaap:NetCashProvidedByUsedInOperatingActivities
dei:LegalEntity

us-gaap:NetCashProvidedByUsedInInvestingActivities
dei:LegalEntity

us-gaap:NetCashProvidedByUsedInFinancingActivities
dei:LegalEntity

us-gaap:NetCashProvidedByUsedInOperatingActivities
dei:LegalEntity
dei:LegalEntity
us-gaap:NetIncomeLoss
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments, dei:LegalEntity
us-gaap:LitigationCase
us-gaap:LitigationCase, dei:LegalEntity

us-gaap:ProfitLoss
dei:LegalEntity
us-gaap:StatementEquityComponents, dei:LegalEntity

us-gaap:IncreaseDecreaseInInventories
dei:LegalEntity

us-gaap:NetCashProvidedByUsedInInvestingActivities
dei:LegalEntity

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment
dei:LegalEntity
us-gaap:ConsolidationItems
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments, dei:LegalEntity

us-gaap:NetCashProvidedByUsedInFinancingActivities
dei:LegalEntity

us-gaap:ProceedsFromIssuanceOfLongTermDebt
dei:LegalEntity

us-gaap:RepaymentsOfLongTermDebt
dei:LegalEntity

us-gaap:RepaymentsOfLongTermDebt
dei:LegalEntity

us-gaap:EffectiveIncomeTaxRateContinuingOperations
dei:LegalEntity
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
us-gaap:AwardType, us-gaap:Vesting

us-gaap:ShareBasedCompensation

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents
dei:LegalEntity
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, dei:LegalEntity
us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis, dei:LegalEntity

us-gaap:ProceedsFromRepaymentsOfShortTermDebt
dei:LegalEntity
us-gaap:LossContingenciesByNatureOfContingency
aee:AggregateNuclearPowerIndustryInsurancePolicyLimitForLossesFromTerroristAttacksWithinTwelveMonthPeriod
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
aee:AmountofMegawatts
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased, dei:LegalEntity
us-gaap:PublicUtilitiesRegulatoryProceeding, dei:LegalEntity

aee:DefinedBenefitPlanNonserviceCostorIncomeComponents
dei:LegalEntity
us-gaap:RetirementPlanType
dei:LegalEntity
aee:DefinedBenefitPlanNonserviceCostorIncomeComponentsTracker

aee:Donations
dei:LegalEntity
us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity

aee:EffectiveIncomeTaxRateReconciliationNondeductibleExpenseAmortizationofExcessDeferredTaxesPercent
dei:LegalEntity
us-gaap:DerivativeInstrumentRisk
aee:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetLiabilityChangeInRealizedUnrealizedGainLossStillHeld
us-gaap:DerivativeInstrumentRisk, dei:LegalEntity
us-gaap:DerivativeInstrumentRisk
aee:FairValueMeasurementWithUnobservableInputsReconciliationRecurringRealizedAndUnrealizedGainsLossesIncludedInRegulatoryAssetsLiabilities
us-gaap:DerivativeInstrumentRisk, dei:LegalEntity
us-gaap:LitigationCase, us-gaap:RegulatoryAgency
aee:IncentiveaddertoFERCallowedbasereturnoncommonequity

aee:Otherrevenuesnotfromcontractswithcustomers
dei:LegalEntity
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments, dei:LegalEntity
us-gaap:DebtInstrument, us-gaap:ShortTermDebtType
aee:PeakShortTermBorrowingsInterestRate
us-gaap:DebtInstrument, us-gaap:ShortTermDebtType, dei:LegalEntity
us-gaap:ShortTermDebtType
us-gaap:ShortTermDebtType, dei:LegalEntity

aee:Revenuesfromalternativerevenueprograms
dei:LegalEntity
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments, dei:LegalEntity
us-gaap:AwardType
aee:SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsGrantedinPeriodFairValue
us-gaap:StatementEquityComponents
us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue

us-gaap:AllowanceForDoubtfulAccountsReceivableWriteOffs
dei:LegalEntity

us-gaap:AmortizationOfFinancingCostsAndDiscounts
dei:LegalEntity

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount

us-gaap:AssetRetirementObligationAccretionExpense
dei:LegalEntity

us-gaap:AssetRetirementObligationLiabilitiesSettled
dei:LegalEntity

us-gaap:CapitalExpendituresIncurredButNotYetPaid
dei:LegalEntity
us-gaap:PropertyPlantAndEquipmentByType
us-gaap:PropertyPlantAndEquipmentByType, dei:LegalEntity

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect
dei:LegalEntity

us-gaap:CommonStockDividendsPerShareCashPaid

us-gaap:DeferredIncomeTaxesAndTaxCredits
dei:LegalEntity
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanInterestCost
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost
us-gaap:RetirementPlanType, dei:LegalEntity
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanServiceCost

us-gaap:DepreciationAmortizationAndAccretionNet
dei:LegalEntity
us-gaap:TradingActivityByType
us-gaap:DerivativeNonmonetaryNotionalAmountEnergyMeasure
us-gaap:TradingActivityByType, dei:LegalEntity
us-gaap:TradingActivityByType
us-gaap:DerivativeNonmonetaryNotionalAmountMass
us-gaap:TradingActivityByType, dei:LegalEntity
us-gaap:TradingActivityByType
us-gaap:DerivativeNonmonetaryNotionalAmountVolume
us-gaap:TradingActivityByType, dei:LegalEntity
us-gaap:StatementEquityComponents
us-gaap:DividendsCommonStockCash
us-gaap:StatementEquityComponents, dei:LegalEntity
us-gaap:DividendsPreferredStockCash

us-gaap:EarningsPerShareBasicAndDiluted

us-gaap:EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
dei:LegalEntity

us-gaap:EffectiveIncomeTaxRateReconciliationNondeductibleExpenseDepreciation
dei:LegalEntity

us-gaap:EffectiveIncomeTaxRateReconciliationOtherAdjustments
dei:LegalEntity

us-gaap:EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount

us-gaap:EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitPercent

us-gaap:EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes
dei:LegalEntity

us-gaap:EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment
dei:LegalEntity

us-gaap:ExciseAndSalesTaxes
dei:LegalEntity
us-gaap:DerivativeInstrumentRisk
us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements
us-gaap:DerivativeInstrumentRisk, dei:LegalEntity

us-gaap:GainLossOnInvestments
dei:LegalEntity

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
dei:LegalEntity

us-gaap:IncreaseDecreaseInAccountsPayableAndAccruedLiabilities
dei:LegalEntity

us-gaap:IncreaseDecreaseInAccruedTaxesPayable
dei:LegalEntity

us-gaap:IncreaseDecreaseInOtherOperatingAssets
dei:LegalEntity

us-gaap:IncreaseDecreaseInOtherOperatingLiabilities
dei:LegalEntity

us-gaap:IncreaseDecreaseInPensionAndPostretirementObligations
dei:LegalEntity

us-gaap:IncreaseDecreaseInReceivables
dei:LegalEntity

us-gaap:IncreaseDecreaseInRegulatoryAssetsAndLiabilities
dei:LegalEntity

us-gaap:IncrementalCommonSharesAttributableToEquityForwardAgreements

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements
us-gaap:RelatedPartyTransaction, dei:LegalEntity
us-gaap:InterestExpenseRelatedParty

us-gaap:InterestIncomeSecuritiesTaxExempt
dei:LegalEntity
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased, dei:LegalEntity
us-gaap:LongTermPurchaseCommitmentAmount
us-gaap:StatementEquityComponents
us-gaap:MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
us-gaap:StatementEquityComponents

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax

us-gaap:OtherIncome
dei:LegalEntity

us-gaap:OtherInterestAndDividendIncome
dei:LegalEntity

us-gaap:OtherNoncashIncomeExpense
dei:LegalEntity

us-gaap:OtherNoninterestExpense
dei:LegalEntity

us-gaap:PaymentOfFinancingAndStockIssuanceCosts
dei:LegalEntity

us-gaap:PaymentsForNuclearFuel
dei:LegalEntity

us-gaap:PaymentsForProceedsFromOtherInvestingActivities
dei:LegalEntity

us-gaap:PaymentsOfDividendsCommonStock

us-gaap:PaymentsOfDividendsMinorityInterest
dei:LegalEntity
us-gaap:PaymentsOfDividendsPreferredStockAndPreferenceStock

us-gaap:PaymentsRelatedToTaxWithholdingForShareBasedCompensation

us-gaap:PaymentsToInvestInDecommissioningFund
dei:LegalEntity
dei:LegalEntity
us-gaap:PreferredStockDividendsIncomeStatementImpact
dei:LegalEntity
us-gaap:ProceedsFromContributionsFromParent
us-gaap:StatementEquityComponents, dei:LegalEntity

us-gaap:ProceedsFromDecommissioningFund
dei:LegalEntity

us-gaap:ProceedsFromIssuanceOfCommonStock
dei:LegalEntity
us-gaap:ProvisionForDoubtfulAccounts

us-gaap:PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
dei:LegalEntity
us-gaap:LitigationCase, us-gaap:Range, us-gaap:RegulatoryAgency
us-gaap:PublicUtilitiesApprovedReturnOnEquityPercentage
us-gaap:LitigationCase, us-gaap:RegulatoryAgency
us-gaap:RegulatoryAgency
us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:SubsequentEventType, dei:LegalEntity
us-gaap:PublicUtilitiesRequestedEquityCapitalStructurePercentage
us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity
us-gaap:PublicUtilitiesRequestedRateIncreaseDecreaseAmount
us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:RegulatoryAsset, us-gaap:SubsequentEventType, dei:LegalEntity
us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:SubsequentEventType, dei:LegalEntity
us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity
us-gaap:PublicUtilitiesRequestedReturnOnEquityPercentage
us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:SubsequentEventType, dei:LegalEntity
us-gaap:Range, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity
us-gaap:Range, us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:SubsequentEventType, dei:LegalEntity
us-gaap:RelatedPartyTransaction, dei:LegalEntity
us-gaap:RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments, us-gaap:SubsegmentsConsolidationItems
us-gaap:RevenueFromRelatedParties
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments, us-gaap:SubsegmentsConsolidationItems, dei:LegalEntity
us-gaap:ConsolidationItems, us-gaap:SubsegmentsConsolidationItems
us-gaap:ConsolidationItems, us-gaap:SubsegmentsConsolidationItems, dei:LegalEntity
us-gaap:RelatedPartyTransaction, dei:LegalEntity
us-gaap:ShortTermDebtType
us-gaap:ShortTermDebtWeightedAverageInterestRateOverTime
us-gaap:DebtInstrument, us-gaap:ShortTermDebtType
us-gaap:ShorttermDebtAverageOutstandingAmount
us-gaap:DebtInstrument, us-gaap:ShortTermDebtType, dei:LegalEntity
us-gaap:ShortTermDebtType
us-gaap:ShortTermDebtType, dei:LegalEntity
us-gaap:DebtInstrument, us-gaap:ShortTermDebtType
us-gaap:ShorttermDebtMaximumAmountOutstandingDuringPeriod
us-gaap:DebtInstrument, us-gaap:ShortTermDebtType, dei:LegalEntity
us-gaap:ShortTermDebtType
us-gaap:ShortTermDebtType, dei:LegalEntity

us-gaap:StockIssued1

us-gaap:StockIssuedDuringPeriodSharesNewIssues

us-gaap:StockIssuedDuringPeriodSharesOther
us-gaap:StatementEquityComponents
us-gaap:StockIssuedDuringPeriodValueNewIssues

us-gaap:TaxesExcludingIncomeAndExciseTaxes
dei:LegalEntity

us-gaap:UtilitiesOperatingExpenseDepreciationAndAmortization
dei:LegalEntity

us-gaap:UtilitiesOperatingExpenseFuelUsed
dei:LegalEntity

us-gaap:UtilitiesOperatingExpenseGasAndPetroleumPurchased
dei:LegalEntity

us-gaap:UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses
dei:LegalEntity
us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity

us-gaap:UtilitiesOperatingExpensePurchasedPower
dei:LegalEntity
us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity

aee:Corporateownedlifeinsuranceborrowings
dei:LegalEntity

aee:DefinedBenefitPlanEstimatedFutureEmployerContributionsOverNextFiveYears
us-gaap:Range
us-gaap:Range
aee:Estimatedcapitalcoststocomplywithexistingandknownfederalandstateairemissionstandards.
us-gaap:Range, dei:LegalEntity
us-gaap:Range, us-gaap:LossContingenciesByNatureOfContingency, dei:LegalEntity
us-gaap:LossContingenciesByNatureOfContingency
aee:InsuranceAggregateMaximumCoverage
us-gaap:LossContingenciesByNatureOfContingency
aee:InsuranceMaximumCoveragePerIncident

aee:Payablesforpurchasedreceivables

aee:ReceivablesPayablesAndAccruedIncomeNet
dei:LegalEntity

aee:RestrictedCashandCashEquivalentsNuclearDecommissioningTrustFund
dei:LegalEntity

dei:EntityCommonStockSharesOutstanding
dei:LegalEntity
us-gaap:AccountsPayableRelatedPartiesCurrent
us-gaap:RelatedPartyTransaction, dei:LegalEntity
dei:LegalEntity
us-gaap:AccountsReceivableRelatedPartiesCurrent
us-gaap:RelatedPartyTransaction, dei:LegalEntity
us-gaap:LossContingenciesByNatureOfContingency
us-gaap:AccrualForEnvironmentalLossContingencies
us-gaap:LossContingenciesByNatureOfContingency, dei:LegalEntity
dei:LegalEntity
us-gaap:AccruedEnvironmentalLossContingenciesCurrent
dei:LegalEntity
us-gaap:AccruedEnvironmentalLossContingenciesNoncurrent

us-gaap:AdditionalPaidInCapital
dei:LegalEntity

us-gaap:AllowanceForDoubtfulAccountsReceivable
dei:LegalEntity

us-gaap:AllowanceForDoubtfulAccountsReceivableCurrent
dei:LegalEntity

us-gaap:AssetRetirementObligation
dei:LegalEntity
us-gaap:RealEstateAndAccumulatedDepreciationDescriptionOfProperty
us-gaap:RealEstateAndAccumulatedDepreciationDescriptionOfProperty, dei:LegalEntity

us-gaap:AssetRetirementObligationsNoncurrent
dei:LegalEntity

us-gaap:AssetsFairValueDisclosure
dei:LegalEntity
us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:FairValueByFairValueHierarchyLevel, dei:LegalEntity

us-gaap:CashSurrenderValueOfLifeInsurance
dei:LegalEntity
dei:LegalEntity
us-gaap:ContractWithCustomerLiabilityCurrent

us-gaap:DecommissioningFundInvestments
dei:LegalEntity

us-gaap:DecommissioningTrustAssetsAmount

us-gaap:DeferredCompensationLiabilityClassifiedNoncurrent
us-gaap:FairValueByMeasurementBasis
us-gaap:DeferredFinanceCostsNet
us-gaap:FairValueByMeasurementBasis, dei:LegalEntity

us-gaap:DeferredIncomeTaxesAndOtherTaxLiabilitiesNoncurrent
dei:LegalEntity
us-gaap:Range, us-gaap:DerivativeInstrumentRisk, us-gaap:MeasurementInputType, us-gaap:ValuationTechnique
us-gaap:DerivativeAssetLiabilityNetMeasurementInput
us-gaap:VariableInterestEntitiesByClassificationOfEntity
us-gaap:EquityMethodInvestments
us-gaap:DerivativeInstrumentRisk
us-gaap:FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
us-gaap:DerivativeInstrumentRisk, dei:LegalEntity
dei:LegalEntity
us-gaap:InterestPayableCurrent
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:InvestmentsFairValueDisclosure
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, dei:LegalEntity
us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis, dei:LegalEntity

us-gaap:LiabilitiesOtherThanLongtermDebtNoncurrent
dei:LegalEntity
us-gaap:FairValueByMeasurementBasis
us-gaap:LongTermDebtAndCapitalLeaseObligations
us-gaap:FairValueByMeasurementBasis, dei:LegalEntity
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:LongTermDebtFairValue
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, dei:LegalEntity
us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis, dei:LegalEntity
us-gaap:Range, us-gaap:LossContingenciesByNatureOfContingency, dei:LegalEntity
us-gaap:LossContingencyEstimateOfPossibleLoss

us-gaap:OtherReceivablesNetCurrent
dei:LegalEntity
dei:LegalEntity
us-gaap:PreferredStockValue
us-gaap:DebtInstrument
us-gaap:RatioOfIndebtednessToNetCapital1
us-gaap:DebtInstrument, dei:LegalEntity

us-gaap:RegulatedEntityOtherAssetsNoncurrent
dei:LegalEntity

us-gaap:RegulatoryAssetsCurrent
dei:LegalEntity

us-gaap:RegulatoryAssetsNoncurrent

us-gaap:RegulatoryLiabilityCurrent
dei:LegalEntity

us-gaap:RegulatoryLiabilityNoncurrent
dei:LegalEntity

us-gaap:RestrictedCashAndCashEquivalentsAtCarryingValue
dei:LegalEntity

us-gaap:RestrictedCashAndCashEquivalentsNoncurrent
dei:LegalEntity

us-gaap:ShortTermBorrowings
dei:LegalEntity
us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis, dei:LegalEntity
us-gaap:ShortTermDebtType
us-gaap:ShortTermDebtType, dei:LegalEntity
us-gaap:DebtInstrument, us-gaap:ShortTermDebtType
us-gaap:ShortTermDebtWeightedAverageInterestRate
us-gaap:DebtInstrument, us-gaap:ShortTermDebtType, dei:LegalEntity
us-gaap:ShortTermDebtType
us-gaap:ShortTermDebtType, dei:LegalEntity
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:ShorttermDebtFairValue
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, dei:LegalEntity
us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis, dei:LegalEntity

us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents, dei:LegalEntity

us-gaap:UnbilledReceivablesCurrent
dei:LegalEntity

us-gaap:UnrecordedUnconditionalPurchaseObligationBalanceOnFifthAnniversary
dei:LegalEntity
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased, dei:LegalEntity

us-gaap:UnrecordedUnconditionalPurchaseObligationBalanceOnFirstAnniversary
dei:LegalEntity
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased, dei:LegalEntity

us-gaap:UnrecordedUnconditionalPurchaseObligationBalanceOnFourthAnniversary
dei:LegalEntity
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased, dei:LegalEntity

us-gaap:UnrecordedUnconditionalPurchaseObligationBalanceOnSecondAnniversary
dei:LegalEntity
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased, dei:LegalEntity

us-gaap:UnrecordedUnconditionalPurchaseObligationBalanceOnThirdAnniversary
dei:LegalEntity
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased, dei:LegalEntity

us-gaap:UnrecordedUnconditionalPurchaseObligationBalanceSheetAmount
dei:LegalEntity
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased, dei:LegalEntity

us-gaap:UnrecordedUnconditionalPurchaseObligationDueAfterFiveYears
dei:LegalEntity
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased, dei:LegalEntity

Tables

  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:CommonStockSharesOutstanding ███▇▇▆▆▄▄▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▂▂▁246246246245245244244243243242242242242242242242242242242242242242242242242242242242242242242242242242242241241240NANANA237NANANA
us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding 248NA247247246NA246245244NA244243NANA242NANANA243NANANA244NANANA245NANANA242NANANANANANANANANANANANANANA
us-gaap:WeightedAverageNumberOfSharesOutstandingBasic 246NA245245244NA244243242NA242242242NA242242242NA242242242NA242242242NA242242242NA242246242NA241241240NA239238237NANANANA
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:RevenueFromContractWithCustomerIncludingAssessedTax ▂▁▄▂▃▂▄▃▃▂▄▃▃▁▅▂▂▁▅▂▃▁▄▂▃▁▃▂▂▂▆▄▄▃█▄▅▄█▄▆▄▅▄▆144013161659137915561419172415631585140217231537151413561859142714341308183314011556137016701419159413221638140314751509200116601658157822681781190417062267172519401684182416961931
 us-gaap:Revenues us-gaap:PublicUtilitiesRegulatoryProceeding,us-gaap:PublicUtility,dei:LegalEntity aee:FinalRateOrder,us-gaap:Electricity,aee:UnionElectricCompany20NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:Revenues us-gaap:PublicUtilitiesRegulatoryProceeding,us-gaap:PublicUtility,dei:LegalEntity aee:PendingRateCase,srt:NaturalGasReserves,aee:AmerenIllinoisCompanyNANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:Revenues us-gaap:PublicUtilitiesRegulatoryProceeding,us-gaap:PublicUtility,us-gaap:SubsequentEventType,dei:LegalEntity aee:PendingRateCase,srt:NaturalGasReserves,us-gaap:SubsequentEvent,aee:AmerenIllinoisCompany46NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OperatingExpenses ▄▂▂▁▆▅▄▃▇▃▂▂▆▄▃▁▄▃▄▃▇▅▁▁█1199113711391099126812531191117813121177114211401260121111681102121411681207116413001245110910971348NA107111421290NA136612972080NA171814651677NA217813941642NANANANA
 us-gaap:OperatingExpenses dei:LegalEntity aee:AmerenIllinoisCompany▅▄▂▂▆▅▂▃▆▄▂▂▄▄▂▂▅▃▃▁▇▅▁▂█535504454443576539451473601524447446531521446435544479466430625536414444654NA389429599NA497478635NA549524720NA564535NANANANANA
 us-gaap:OperatingExpenses dei:LegalEntity aee:UnionElectricCompany▃▁▄▂▄▆▇▅▅▃▅▅▇▅▇▄▄▅█▇▄▆▅▃▅654623678646679706735697702659698698737696734670678696748738685710703657698NA676710685NA635575613NA782646695NA675564NANANANANA
us-gaap:OperatingIncomeLoss ▇▇█▇▇▇█▇▇▇█▇▇▆█▇▇▆█▇▇▆█▇▇▇█▇▇▁█▇▅▆█▇▇▇▆▇▇▇▇▇▇241179520280288166533385273225581398254145691325220140626237256125561322246171567261185-1816635363-42214855031622719889331298245485365321
 us-gaap:OperatingIncomeLoss dei:LegalEntity aee:AmerenIllinoisCompany▆▅▃▃▆▄▃▃▅▅▄▄▆▂█▃▄▂▆▂▄▃▅▂▄▂▅▂▂▁▅▂▂▂▇▃▂1881501101041861351131051591501281301727423010713374189831209715875120851588785511518689751969988NA182112NANANANANA
 us-gaap:OperatingIncomeLoss dei:LegalEntity aee:UnionElectricCompany▁▁▇▃▂▁▇▅▂▂█▅▂▂█▄▂▂█▃▃▁▇▅▃▂█▄▃▂█▅▂▁▆▄▂265381152797394258904041723753544311976358423146115293942431199641717911169429269782333317677NA385197NANANANANA
us-gaap:InterestExpense ▆▅▇▇▇▇███▇▇▇▇▆▇▆▆▅▄▅▄▁▄▅▆93919697979910110010196979999959795959187898875858992NA88100101NA113112113NA113104119NA130115132NANANANA
 us-gaap:InterestExpense dei:LegalEntity aee:AmerenIllinoisCompany█▇█▇▇▇█▇▇▆▇▇▇▆▆▆▆▅▆▆▆▁▅▄▄39363836373738373735363637353535353233333322312930NA313431NA343133NA333535NA3734NANANANANA
 us-gaap:InterestExpense dei:LegalEntity aee:UnionElectricCompany▁▂▃▃▄▅▆▆▆▆▆▇█▇▇▇▇████▇▇█▇40424445474850515150505354535353525554555552535452NA435660NA555656NA544554NA5643NANANANANA
us-gaap:OtherNonoperatingIncomeExpense ▄▇██▆▄▇▆▅▂▂▂▁▂▂▂▃▂▃▂▁▄▃▄▂213134362918322923121196910101312141081714179NA15117NA10132NA131211NA142215NANANANA
 us-gaap:OtherNonoperatingIncomeExpense dei:LegalEntity aee:AmerenIllinoisCompany▆█▇█▆▇▆▇▄▃▃▃▁▄▃▃▂▄▃▃▃▄▃▄▂11141315111211136211-351304122424-1NA11-2NA0NA-10NANANA1NANA1NANANANANA
 us-gaap:OtherNonoperatingIncomeExpense dei:LegalEntity aee:UnionElectricCompany▁▇▇█▆▅██▆▄▅▄▄▄▆▃▆▆▅▄▃▆▅▇▄4151516121116161310119101012713121110813111410NA14119NA111412NA141310NA1519NANANANANA
us-gaap:IncomeTaxExpenseBenefit ▁▁▃▂▁▁▄▃▂▇▇▄▂▁█▃▁▁▇▂▃▁▇▄▃212492392716105744220020511457262339231302085966201949964NA1876635NA15854-130NA1638545NA1378375NANANANA
 us-gaap:IncomeTaxExpenseBenefit dei:LegalEntity aee:AmerenIllinoisCompany▄▃▂▂▄▂▂▂▃▄▄▄▅▁█▃▄▁▆▂▃▃▅▂▃39312020392523183239383752147729381359203533542135NA512220NA462218NA652620NA5431NANANANANA
 us-gaap:IncomeTaxExpenseBenefit us-gaap:PublicUtilitiesRegulatoryProceeding,us-gaap:PublicUtility,dei:LegalEntity aee:FinalRateOrder,us-gaap:Electricity,aee:UnionElectricCompany20NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:ProfitLoss ▇▇█▇▇▇█▇▇▆█▇▇▆█▇▇▆█▇▇▇█▇▇▆█▇▆▁█▇▄1489536618019369359240153-59290194104333711481073034515111049295150983830496-143-1155374210-403NA28713974NA-164155106NANANANA
 us-gaap:ProfitLoss dei:LegalEntity aee:AmerenIllinoisCompany█▆▄▄█▅▄▄▆▅▃▃▅▁█▂▃▁▆▁▃▂▄▁▃12197656312185636396785558803011946603398325446752954NA773232NA713328NA983834NA11057NANANANANA
 us-gaap:ProfitLoss us-gaap:StatementEquityComponents,dei:LegalEntity us-gaap:RetainedEarnings,aee:AmerenIllinoisCompany█▅▁▁█▄▁▁121976563121856363NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:ComprehensiveIncomeNetOfTax ▄▄█▅▅▃█▆▄▁▇▅▄▂█▄▄▂█▄▄▂▇▄▄1479836417919263359237152-5728819510211368151103313431541083329315296NA292101-152NA406216-388NA28113768NANANANANANANANA
us-gaap:ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest █▁█▁█▁█▁█▁█▁█▁█▁█21212121212121212NANANANANANANANANANANANANA9-1NANA21NANANANANANANANANA
us-gaap:ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest ▄▄█▅▅▃█▆▄▁▇▅▄▂█▄▄1499936618019464361238154-5629019610412370152105NANANANANANANANANANANANANA415215-388NA28313871NA-164146118NANANANA
 us-gaap:NetIncomeLoss dei:LegalEntity aee:AmerenIllinoisCompany█▆▄▄█▆▄▄▆▅▄▄▅▂█▃▄▂▇▂▄▃▅▂▄▂▅▂▂▁▅▂▂▂▇▃▂12096656212084636295775557792711946603398325446752954227732321271332826983834NANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:ConsolidationItems,us-gaap:StatementBusinessSegments us-gaap:OperatingSegments,aee:AmerenIllinoisElectricDistribution▅█▂▅▅▄▄▃▃▅▂▃▁37413237363535333337313330NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:ConsolidationItems,us-gaap:StatementBusinessSegments us-gaap:OperatingSegments,aee:AmerenIllinoisGas█▄▁▁█▄▁▂▆▄▁▂▅5527-1157210742202533NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:ConsolidationItems,us-gaap:StatementBusinessSegments us-gaap:OperatingSegments,aee:AmerenTransmission▆▅█▄▅▄▆▂▂▁▂▁▁47465342444348363734383434NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:ConsolidationItems,us-gaap:StatementBusinessSegments us-gaap:OperatingSegments,aee:OtherSegment█▇▆▇█▇▆▇▇▁▆▇▇170-20-815-9-20-51-115-1710NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:ConsolidationItems,us-gaap:StatementBusinessSegments,dei:LegalEntity us-gaap:OperatingSegments,aee:AmerenIllinoisElectricDistribution,aee:AmerenIllinoisCompany▅█▁▅▄▃▃▂3741323736353533NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:ConsolidationItems,us-gaap:StatementBusinessSegments,dei:LegalEntity us-gaap:OperatingSegments,aee:AmerenIllinoisGas,aee:AmerenIllinoisCompany█▄▁▁█▄▁▂5527-11572107NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:ConsolidationItems,us-gaap:StatementBusinessSegments,dei:LegalEntity us-gaap:OperatingSegments,aee:AmerenIllinoisTransmission,aee:AmerenIllinoisCompany▄▄█▂▄▄▄▁2828342427282822NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:LitigationCase aee:February2015FERCROEComplaintCase11NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:LitigationCase,dei:LegalEntity aee:February2015FERCROEComplaintCase,aee:AmerenIllinoisCompany6NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic ▄▄█▅▅▃█▆▄▁▇▅▄1469436417919168357239151-60288193102NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic us-gaap:StatementEquityComponents us-gaap:RetainedEarnings▃▂█▄▄▁█▅▃1469436417919168357239151NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:NetIncomeLossAttributableToNoncontrollingInterest █▁█▁█▁█▁█▁█▁█▁█▁█21212121212121212NANANANANANANANANANA12NA0-12NA213NA334NANANANA
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:Assets ██▇▇▇▆▆▆▅▅▅▅▄▄▄▃▃▃▃▃▃▂▂▁▁▁▂▂▂▂▃▃▃▃▃▃▃▃2927228933285462810327509272152695926639260792594525617252542481124699241342379323385236402345923152228842267621876215882116621042223852227621952218352349822980228992364523356233912332923515NANANA23702NANANA
 us-gaap:Assets dei:LegalEntity aee:AmerenIllinoisCompany██▇▇▇▇▆▆▅▅▅▅▄▄▄▄▃▃▃▃▃▃▂▂▂▂▁▁▁▁▁▁▁▁▁▁12433121851194611724114941131911010107711047110345100229801956994749202899989448903865685008456838179837719764074547439736672887282722771277256721370647154NA7406NANANANANANANA
 us-gaap:Assets dei:LegalEntity aee:UnionElectricCompany███▇▆▆▆▆▅▅▅▅▅▅▅▄▄▅▅▄▄▄▃▃▂▂▃▃▂▂▂▁▁▂▁▁149931493714860146981437114291143831439214040140431406814005138141403513889136491344313851139411372113555135411317913203129481290413231131311286713043129671268012546127571263812527NA12504NANANANANANANA
us-gaap:LiabilitiesAndStockholdersEquity ██▇▇▇▆▆▆▅▅▅▅▄▄▄▃▃▃▃▃▃▂▂▁▁▁▂▂▂▂▃▃▃▃▃▃▃▃2927228933285462810327509272152695926639260792594525617252542481124699241342379323385236402345923152228842267621876215882116621042223852227621952218352349822980228992364523356233912332923515NANANA23702NANANA
 us-gaap:LiabilitiesAndStockholdersEquity dei:LegalEntity aee:AmerenIllinoisCompany██▇▇▇▇▆▆▅▅▅▅▄▄▄▄▃▃▃▃▃▃▂▂▂▂▁▁▁▁▁▁▁▁▁▁12433121851194611724114941131911010107711047110345100229801956994749202899989448903865685008456838179837719764074547439736672887282722771277256721370647154NA7406NANANANANANANA
 us-gaap:LiabilitiesAndStockholdersEquity dei:LegalEntity aee:UnionElectricCompany███▇▆▆▆▆▅▅▅▅▅▅▅▄▄▅▅▄▄▄▃▃▂▂▃▃▂▂▂▁▁▂▁▁149931493714860146981437114291143831439214040140431406814005138141403513889136491344313851139411372113555135411317913203129481290413231131311286713043129671268012546127571263812527NA12504NANANANANANANA
us-gaap:StockholdersEquity ███▇▆▆▆▅▅▄▅▄▄▄▄▃▃▃▄▃▂▂▃▂▂▂▂▁▁▂▇▆▅▇8085805980627791770576317656738672307184734571587064710371936922686969467014676467046713677465726513654465746374636566167874755574327919NANA77257730NANANA7856NANANA
 us-gaap:StockholdersEquity dei:LegalEntity aee:AmerenIllinoisCompany█▇▇▇▆▆▅▅▅▄▄▄▄▃▃▃▃▃▃▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁435241324021395638943774361035473425331032253170311330343021293829252897284127422713266126022527250024482493243124162401244724342441245225022493NA2576NANANA3072NANANA
 us-gaap:StockholdersEquity dei:LegalEntity aee:UnionElectricCompany▇▇█▆▆▅▇▅▃▃▃▂▂▃▄▁▁▃▃▁▂▂▃▂▁▂▃▂▂▂▄▂▁▂▅▄433943494425427542684229435642374069408141174043403540904147397939564082411839543994405241214011396339934096399840044054413740013958403742354130NA4153NANANA4057NANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:Parent███▆▅▄▅▃▁▁8085805980627791770576317656738672307184NANANA7103NANANA6946NANANA6713NANANA6544NANANA6616NANANA7919NANANA7730NANANANANANANA
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:AssetsCurrent ▁▁▁▁▁▁▂▂▂▂▂▂▁▂▂▂▁▃▃▃▃▃▃▃▂▃███▄▄▄▃▄▅▅▆▆14641431149515141422153316401685156716121581157114501593159915941458191719831991199320461942196518401972327334083296236924062154212422952680260327152894NANANA2842NANANA
 us-gaap:AssetsCurrent dei:LegalEntity aee:AmerenIllinoisCompany▁▁▁▁▂▂▂▁▂▂▁▁▁▂▂▁▂▃▂▂▄▄▂▁▂▂▂▃▃▃▄▅▆▆▇█5716146096126576766295766266726026065926836175826867606327028118446856056776336257107477498749061061101711081201NA1438NANANANANANANA
 us-gaap:AssetsCurrent dei:LegalEntity aee:UnionElectricCompany▂▂▃▃▁▂▄▆▃▃▄▃▁▄▆▄▁▆█▅▄▄▄▅▃▃▆▆▄▆▆▄▃▆█▅858814882902751832104211729019059649507881004114797478811861325110096410391021111794895911651133979115911911023888113413391125NA1275NANANANANANANA
us-gaap:CashAndCashEquivalentsAtCarryingValue ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▄▂▁▁▁▁▁▁▁▃▃▃▃▄▂▃▄▇▅▇▇█▇▅█421620681611293010910891813132927226513462630169150161209298117208255522378573545608506360622NANANA
 us-gaap:CashAndCashEquivalentsAtCarryingValue dei:LegalEntity aee:AmerenIllinoisCompany▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▂▁▁▁▁▁▁▁▁▁▂▂▁▂▂▄▁▃▄█▅▅▆600000003000003007100011211198930936018721116253508322285383NA306NANANA
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  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:PropertyPlantAndEquipmentNet ██▇▇▇▇▆▆▆▆▅▅▅▅▄▄▄▄▃▃▃▃▂▂▂▂▁▁▁▂▃▃▃▃▃▃▃▃2467824376238942347923044228102237921998216662146620906205892029820113196471932419000187991830717986177001742416991167261642516205158341560115408160961783317690175351812717873179451788817853NANANA17610NANANA
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  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
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  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
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  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
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  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
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us-gaap:ProfitLoss ▇▇█▇▇▇█▇▇▆█▇▇▆█▇▇▆█▇▇▇█▇▇▆█▇▆▁█▇▄1489536618019369359240153-59290194104333711481073034515111049295150983830496-143-1155374210-403NA28713974NA-164155106NANANANA
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 us-gaap:ProfitLoss us-gaap:StatementEquityComponents,dei:LegalEntity us-gaap:RetainedEarnings,aee:AmerenIllinoisCompany█▅▁▁█▄▁▁121976563121856363NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:IncreaseDecreaseInInventories ▄▅▇▆▁▃▇▆▂▃▆▇▂▄▆▆▂▄▇▇▁▃█-2365431-81-435022-68-373446-60-243632-55-94850-75-3769NA-102NANANA-127NA71NA-80NANANA-135NANANA-148NANANANA
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us-gaap:NetCashProvidedByUsedInInvestingActivities ▁▂▂▄▄▃▄▅▃▃▅▆▅▄▆▅▆▃▇██▆█-684-637-644-587-567-617-590-532-597-620-526-520-539-590-516-525-510-614-487-436-439-505-442NA-313NANANA-303NA-373NA-326NANANA-250NANANA-317NANANANA
us-gaap:PaymentsToAcquirePropertyPlantAndEquipment ███▆▅▆▆▄▆▇▄▃▄▆▃▄▃▆▃▁▁▃▁636650636581544597577533579609525494504580496504496585486429417475427NA442NANANA275NA340NA282NANANA227NANANA289NANANANA
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 us-gaap:PaymentsToAcquirePropertyPlantAndEquipment us-gaap:ConsolidationItems,us-gaap:StatementBusinessSegments,dei:LegalEntity us-gaap:OperatingSegments,aee:AmerenIllinoisElectricDistribution,aee:AmerenIllinoisCompany▄▅█▅▄▁▇▆123128139127124114135132NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:PaymentsToAcquirePropertyPlantAndEquipment us-gaap:ConsolidationItems,us-gaap:StatementBusinessSegments,dei:LegalEntity us-gaap:OperatingSegments,aee:AmerenIllinoisTransmission,aee:AmerenIllinoisCompany█▃▂▁▂▆▃▃14010392859212399104NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
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us-gaap:ProceedsFromIssuanceOfLongTermDebt ▅▆▅▁▅▅▁█▁▅▃465627450045049908530496300NANA2400NANA9480NANA3000NANANANANANANANANANANANANANANANANANANANANANA
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us-gaap:RepaymentsOfLongTermDebt 85NA00329NA1993230NA04250NA0129260NA01140NA0529163NANANANANANANANANANANANANANANANANANANANA
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  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:RepaymentsOfLongTermDebt 85NA00329NA1993230NA04250NA0129260NA01140NA0529163NANANANANANANANANANANANANANANANANANANANA
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Common Stock Value

Common Stock Par Or Stated Value Per Share

Common Stock Shares Outstanding

us-gaap:CommonStockSharesOutstanding



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-312008-12-31
Value246246246245245244244243243242242242242242242242242242242242242242242242242242242242242242242242242242242241241240237212
Percentage of CommonStockSharesOutstanding100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Common Stock Shares Authorized

Weighted Average Number Of Diluted Shares Outstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302016-09-302015-09-302014-09-302013-09-302012-09-30
Value248247247246246245244244243242243244245242
Percentage of WeightedAverageNumberOfDilutedSharesOutstanding100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Weighted Average Number Of Shares Outstanding Basic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value246245245244244243242242242242242242242242242242242242242242242242242246242241241240239238237
Percentage of WeightedAverageNumberOfSharesOutstandingBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Basic

Earnings Per Share Diluted

Income Loss From Continuing Operations Per Basic Share

Income Loss From Continuing Operations Per Diluted Share

Revenue From Contract With Customer Including Assessed Tax

us-gaap:RevenueFromContractWithCustomerIncludingAssessedTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
Value144013161659137915561419172415631585140217231537151413561859142714341308183314011556137016701419159413221638140314751509200116601658157822681781190417062267172519401684182416961931
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Revenues

us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity

us-gaap:Revenues

aee:FinalRateOrder, us-gaap:Electricity, aee:UnionElectricCompany



Period End2020-03-31
Value20
Percentage of Revenues100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax1.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:FinalRateOrder us-gaap:Electricity aee:UnionElectricCompany0.0

aee:PendingRateCase, srt:NaturalGasReserves, aee:AmerenIllinoisCompany



Period End2020-02-29
Value46
Percentage of Revenues0.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax0.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:PendingRateCase srt:NaturalGasReserves aee:AmerenIllinoisCompany0.0

us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, us-gaap:SubsequentEventType, dei:LegalEntity

aee:PendingRateCase, srt:NaturalGasReserves, us-gaap:SubsequentEvent, aee:AmerenIllinoisCompany



Period End2020-03-31
Value46
Percentage of Revenues230.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax3.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:PendingRateCase srt:NaturalGasReserves us-gaap:SubsequentEvent aee:AmerenIllinoisCompany0.0

Cost Depreciation Amortization And Depletion

Operating Expenses

us-gaap:OperatingExpenses



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value1199113711391099126812531191117813121177114211401260121111681102121411681207116413001245110910971348107111421290136612972080171814651677217813941642
Percentage of OperatingExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax83.386.468.779.781.588.369.175.482.884.066.374.283.289.362.877.284.789.365.883.183.590.966.477.384.665.481.487.568.378.1125.575.782.388.196.180.884.6

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value535504454443576539451473601524447446531521446435544479466430625536414444654389429599497478635549524720564535
Percentage of OperatingExpenses44.644.339.940.345.443.037.940.245.844.539.139.142.143.038.239.544.841.038.636.948.143.137.340.548.536.337.646.436.436.930.532.035.842.925.938.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax37.238.327.432.137.038.026.230.337.937.425.929.035.138.424.030.537.936.625.430.740.239.124.831.341.023.730.640.624.828.838.324.229.437.824.931.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany74.077.180.581.075.680.080.081.879.177.777.977.475.587.666.080.380.486.671.183.883.984.772.485.584.571.183.187.676.784.887.773.784.189.175.682.7

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value654623678646679706735697702659698698737696734670678696748738685710703657698676710685635575613782646695675564
Percentage of OperatingExpenses54.554.859.558.853.556.361.759.253.556.061.161.258.557.562.860.855.859.662.063.452.757.063.459.951.863.162.253.146.544.329.545.544.141.431.040.5
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax45.447.340.946.843.649.842.644.644.347.040.545.448.751.339.547.047.353.240.852.744.051.842.146.343.841.350.646.431.734.637.034.536.336.529.832.7
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany96.299.264.081.089.699.065.173.088.694.362.574.793.392.863.077.391.592.363.983.585.696.164.173.085.461.879.986.159.768.188.770.178.690.063.774.1

Operating Income Loss

us-gaap:OperatingIncomeLoss



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
Value241179520280288166533385273225581398254145691325220140626237256125561322246171567261185-1816635363-42214855031622719889331298245485365321
Percentage of OperatingIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax16.713.631.320.318.511.730.924.617.216.033.725.916.810.737.222.815.310.734.216.916.59.133.622.715.412.934.618.612.5-120.331.721.9-25.59.424.317.711.911.63.919.215.414.526.621.516.6

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value1881501101041861351131051591501281301727423010713374189831209715875120851588785511518689751969988182112
Percentage of OperatingIncomeLoss78.083.821.237.164.681.321.227.358.266.722.032.767.751.033.332.960.552.930.235.046.977.628.223.348.849.727.933.345.9-2.823.823.7-21.150.735.631.338.8204.533.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax13.111.46.67.512.09.56.66.710.010.77.48.511.45.512.47.59.35.710.35.97.77.19.55.37.56.49.66.25.83.47.55.25.44.88.65.64.68.06.5
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany26.022.919.519.024.420.020.018.220.922.322.322.624.512.434.019.719.613.428.916.216.115.327.614.515.515.128.916.912.48.723.315.212.312.326.315.910.924.417.3

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value265381152797394258904041723753544311976358423146115293942431199641717911169429269782333317677385197
Percentage of OperatingIncomeLoss10.82.873.354.327.44.273.967.033.017.871.859.520.937.262.460.628.641.467.661.644.923.270.275.548.456.173.568.660.0-3.867.674.1-18.515.560.555.733.9432.659.5
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax1.80.423.011.05.10.522.916.55.72.924.215.43.54.023.213.84.44.423.110.47.42.123.617.17.57.325.512.87.54.621.416.24.71.514.79.94.017.011.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany3.80.836.019.010.41.034.927.011.45.737.425.46.77.237.022.78.57.736.116.514.43.935.927.014.612.638.220.113.910.340.331.911.33.429.921.410.036.325.9

Interest Expense

us-gaap:InterestExpense



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value9391969797991011001019697999995979595918789887585899288100101113112113113104119130115132
Percentage of InterestExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax6.56.95.87.06.27.05.96.46.46.85.66.46.57.05.26.76.67.04.76.45.75.55.16.35.85.47.16.85.66.76.85.05.86.25.76.76.8

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value393638363737383737353636373535353532333333223129303134313431333335353734
Percentage of InterestExpense41.939.639.637.138.137.437.637.036.636.537.136.437.436.836.136.836.835.237.937.137.529.336.532.632.635.234.030.730.127.729.229.233.729.428.529.6
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax2.72.72.32.62.42.62.22.42.32.52.12.32.42.61.92.52.42.41.82.42.11.61.92.01.91.92.42.11.71.92.01.52.01.81.62.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany5.45.56.76.64.95.56.76.44.95.26.36.25.35.95.26.55.25.85.06.44.43.55.45.63.95.76.64.55.25.54.64.45.64.35.05.3

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value404244454748505151505053545353535255545555525354524356605556565445545643
Percentage of InterestExpense43.046.245.846.448.548.549.551.050.552.151.553.554.555.854.655.854.760.462.161.862.569.362.460.756.548.956.059.448.750.049.647.843.345.443.137.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax2.83.22.73.33.03.42.93.33.23.62.93.43.63.92.93.73.64.22.93.93.53.83.23.83.32.64.04.12.73.43.42.42.52.82.52.5
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany5.96.74.25.66.26.74.45.36.47.24.55.76.87.14.56.17.07.34.66.26.97.04.86.06.43.96.37.55.26.68.14.85.57.05.35.7

Other Nonoperating Income Expense

us-gaap:OtherNonoperatingIncomeExpense



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value2131343629183229231211969101013121410817141791511710132131211142215
Percentage of OtherNonoperatingIncomeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax1.52.42.02.61.91.31.91.91.50.90.60.60.40.70.50.70.90.90.80.70.51.20.81.20.60.90.80.50.50.80.10.60.70.60.61.30.8

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-03-312011-03-312010-06-30
Value11141315111211136211-351304122424-111-20-1011
Percentage of OtherNonoperatingIncomeExpense52.445.238.241.737.966.734.444.826.116.79.111.1-50.055.610.030.00.033.37.120.025.023.514.323.5-11.16.79.1-28.60.0-500.09.14.5
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax0.81.10.81.10.70.80.60.80.40.10.10.1-0.20.40.10.20.00.30.10.10.10.30.10.3-0.10.10.1-0.10.0-0.60.10.1
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany1.52.12.32.71.41.82.02.20.80.30.20.2-0.40.80.10.60.00.70.20.40.30.60.30.8-0.10.20.2-0.30.0-1.40.10.2

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value4151516121116161310119101012713121110813111410141191114121413101519
Percentage of OtherNonoperatingIncomeExpense19.048.444.144.441.461.150.055.256.583.3100.0100.0166.7111.1120.070.0100.0100.078.6100.0100.076.578.682.4111.193.3100.0128.6110.0107.7600.0107.7108.390.9107.186.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax0.31.10.91.20.80.80.91.00.80.70.60.60.70.70.60.50.90.90.60.70.50.90.71.00.60.90.80.60.50.80.70.60.70.50.71.1
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany0.62.41.42.01.61.51.41.71.61.41.01.01.31.31.00.81.81.60.91.11.01.81.01.61.21.31.21.11.01.71.71.31.61.31.42.5

Income Loss From Continuing Operations

Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest

Income Loss From Continuing Operations Attributable To Noncontrolling Entity

Income Tax Expense Benefit

us-gaap:IncomeTaxExpenseBenefit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value212492392716105744220020511457262339231302085966201949964187663515854-13016385451378375
Percentage of IncomeTaxExpenseBenefit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax1.51.85.52.81.71.16.14.72.614.311.97.43.81.912.56.42.22.311.34.24.21.511.67.04.011.44.72.47.93.3-7.87.24.82.46.04.83.9

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value393120203925231832393837521477293813592035335421355122204622186526205431
Percentage of IncomeTaxExpenseBenefit185.7129.221.751.3144.4156.221.924.376.219.518.532.591.253.833.031.5122.643.328.433.953.0165.027.821.254.727.333.357.129.140.7-13.839.930.644.439.437.3
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax2.72.41.21.52.51.81.31.22.02.82.22.43.41.04.12.02.61.03.21.42.22.43.21.52.23.11.61.42.31.31.12.91.51.12.41.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany5.44.73.53.75.13.74.13.14.25.86.66.47.42.411.45.45.62.49.03.94.75.29.44.04.59.34.32.97.13.92.58.74.22.57.24.8

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value-1-251154-865541336143723114858941403926-5129762914949191488312102531112058
Percentage of IncomeTaxExpenseBenefit-4.8-8.355.438.514.8-50.061.973.031.018.069.863.25.33.863.563.029.013.367.366.139.4-25.066.576.845.379.774.254.393.7153.7-9.262.662.424.487.669.9
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-0.1-0.23.11.10.3-0.63.83.50.82.68.34.70.20.18.04.10.60.37.62.81.7-0.47.75.41.89.13.51.37.45.00.74.53.00.65.33.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany-0.1-0.34.81.90.5-1.15.85.71.65.212.87.70.40.112.76.71.20.512.04.43.2-0.711.88.43.513.65.52.413.99.81.79.16.41.411.37.6

us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity

aee:FinalRateOrder, us-gaap:Electricity, aee:UnionElectricCompany



Period End2020-03-31
Value20
Percentage of IncomeTaxExpenseBenefit95.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax1.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:FinalRateOrder us-gaap:Electricity aee:UnionElectricCompany0.0

Income Taxes Paid Net

Profit Loss

us-gaap:ProfitLoss



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value1489536618019369359240153-59290194104333711481073034515111049295150983830496-143-1155374210-40328713974-164155106
Percentage of ProfitLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax10.37.222.113.112.44.920.815.49.7-4.216.812.66.92.420.010.47.52.318.810.87.13.617.710.66.12.918.66.8-9.7-76.518.712.7-24.312.77.83.9-7.29.05.5

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value1219765631218563639678555880301194660339832544675295477323271332898383411057
Percentage of ProfitLoss81.8102.117.835.062.7123.217.526.262.7-132.219.029.976.990.932.131.156.1110.028.421.249.193.925.419.355.125.333.3-22.419.015.7-6.934.127.345.9-67.136.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax8.47.43.94.67.86.03.74.06.15.63.23.85.32.26.43.24.22.55.32.33.53.44.52.03.44.72.32.23.52.01.74.32.11.84.93.3
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany16.714.811.511.515.912.611.210.912.611.69.610.111.45.017.68.58.96.015.06.27.27.313.15.67.014.16.24.711.05.93.913.26.14.214.78.8

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value-9-2030110840-2229516939-362351216102429315112406242-5223127482398541237144221919122224115
Percentage of ProfitLoss-6.1-21.182.260.020.7-31.982.270.425.561.081.062.45.830.365.262.814.036.769.641.138.2-10.275.684.749.078.688.5-28.763.468.6-5.566.665.529.7-136.674.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-0.6-1.518.17.82.6-1.617.110.82.5-2.613.67.90.40.713.06.51.00.813.14.42.7-0.413.48.93.014.66.12.811.88.71.38.45.11.29.96.7
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany-1.3-3.228.413.55.3-3.126.117.74.9-5.221.113.00.81.320.810.72.01.520.57.05.2-0.720.314.15.921.99.65.222.317.13.217.111.12.821.115.1

us-gaap:StatementEquityComponents, dei:LegalEntity

us-gaap:RetainedEarnings, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value121976563121856363
Percentage of ProfitLoss81.8102.117.835.062.7123.217.526.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax8.47.43.94.67.86.03.74.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:RetainedEarnings aee:AmerenIllinoisCompany0.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value-9-2030110840-22295169
Percentage of ProfitLoss-6.1-21.182.260.020.7-31.982.270.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-0.6-1.518.17.82.6-1.617.110.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:RetainedEarnings aee:UnionElectricCompany0.00.00.00.00.00.00.00.0

Comprehensive Income Net Of Tax

us-gaap:ComprehensiveIncomeNetOfTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-31
Value1479836417919263359237152-5728819510211368151103313431541083329315296292101-152406216-38828113768
Percentage of ComprehensiveIncomeNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax10.27.421.913.012.34.420.815.29.6-4.116.712.76.70.819.810.67.22.418.711.06.92.417.510.76.017.87.2-10.320.313.0-23.412.47.73.6

Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest

us-gaap:ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312012-09-302012-06-302011-09-302011-06-30
Value212121212121212129-121
Percentage of ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax0.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.4-0.10.10.1

Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest

us-gaap:ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value1499936618019464361238154-5629019610412370152105415215-38828313871-164146118
Percentage of ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax10.37.522.113.112.54.520.915.29.7-4.016.812.86.90.919.910.77.320.713.0-23.412.57.73.7-7.28.56.1

Net Income Loss

dei:LegalEntity

us-gaap:NetIncomeLoss

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value12096656212084636295775557792711946603398325446752954227732321271332826983834
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax8.37.33.94.57.75.93.74.06.05.53.23.75.22.06.43.24.22.55.32.33.53.44.52.03.41.74.72.32.20.83.52.01.71.64.32.11.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany16.614.711.511.315.712.511.210.712.511.49.69.911.24.517.68.58.96.015.06.27.27.313.15.67.03.914.16.24.72.011.05.93.94.313.26.14.2

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value-10-2030010739-2229416838-36234120572429315112406242-5223127483323985411623714422-141919122
Percentage of NetIncomeLoss-8.3-20.8461.5172.632.5-26.2466.7271.040.0-46.8425.5210.56.325.9203.4202.225.033.3244.9193.877.8-10.9297.3437.988.9150.0310.4265.6128.1133.3333.8436.478.6-53.8194.9239.564.7
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-0.7-1.518.17.82.5-1.617.110.72.4-2.613.67.80.30.513.06.51.00.813.14.42.7-0.413.48.93.02.514.66.12.81.111.88.71.3-0.98.45.11.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany-1.5-3.228.313.45.1-3.126.017.64.8-5.221.012.80.60.920.810.72.01.520.57.05.2-0.720.314.15.94.321.99.65.22.422.317.13.2-2.117.111.12.8

us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, aee:AmerenIllinoisElectricDistribution



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value37413237363535333337313330
Percentage of NetIncomeLoss30.842.749.259.730.041.755.653.234.748.156.457.938.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax2.63.11.92.72.32.52.02.12.12.61.82.12.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:AmerenIllinoisElectricDistribution9.50.08.210.39.30.08.98.58.20.07.78.50.0

us-gaap:OperatingSegments, aee:AmerenIllinoisGas



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value5527-1157210742202533
Percentage of NetIncomeLoss45.828.1-1.51.647.525.00.011.344.226.03.68.841.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax3.82.1-0.10.13.71.50.00.42.61.40.10.32.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:AmerenIllinoisGas20.30.0-0.90.717.80.00.04.913.50.01.83.70.0

us-gaap:OperatingSegments, aee:AmerenTransmission



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value47465342444348363734383434
Percentage of NetIncomeLoss39.247.981.567.736.751.276.258.138.944.269.159.643.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax3.33.53.23.02.83.02.82.32.32.42.22.22.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:AmerenTransmission38.20.041.438.538.60.042.535.035.60.031.932.40.0

us-gaap:OperatingSegments, aee:OtherSegment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value170-20-815-9-20-51-115-1710
Percentage of NetIncomeLoss14.20.0-30.8-12.912.5-10.7-31.7-8.11.1-149.4-30.91.80.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax1.20.0-1.2-0.61.0-0.6-1.2-0.30.1-8.2-1.00.10.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:OtherSegment0.00.00.00.00.00.00.00.00.00.0850.050.00.0

us-gaap:OperatingSegments, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-03-31
Value-10-2030010739-2229416838-362345
Percentage of NetIncomeLoss-8.3-20.8461.5172.632.5-26.2466.7271.040.0-46.8425.56.3
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-0.7-1.518.17.82.5-1.617.110.72.4-2.613.60.3
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:UnionElectricCompany-1.50.028.313.45.10.026.017.64.80.021.00.0

us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments, dei:LegalEntity

us-gaap:OperatingSegments, aee:AmerenIllinoisElectricDistribution, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value3741323736353533
Percentage of NetIncomeLoss30.842.749.259.730.041.755.653.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax2.63.11.92.72.32.52.02.1
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:AmerenIllinoisElectricDistribution aee:AmerenIllinoisCompany0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, aee:AmerenIllinoisGas, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value5527-11572107
Percentage of NetIncomeLoss45.828.1-1.51.647.525.00.011.3
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax3.82.1-0.10.13.71.50.00.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:AmerenIllinoisGas aee:AmerenIllinoisCompany0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, aee:AmerenIllinoisTransmission, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value2828342427282822
Percentage of NetIncomeLoss23.329.252.338.722.533.344.435.5
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax1.92.12.01.71.72.01.61.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:AmerenIllinoisTransmission aee:AmerenIllinoisCompany0.00.00.00.00.00.00.00.0

us-gaap:LitigationCase

aee:February2015FERCROEComplaintCase



Period End2020-03-31
Value11
Percentage of NetIncomeLoss9.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax0.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:February2015FERCROEComplaintCase0.0

us-gaap:LitigationCase, dei:LegalEntity

aee:February2015FERCROEComplaintCase, aee:AmerenIllinoisCompany



Period End2020-03-31
Value6
Percentage of NetIncomeLoss5.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax0.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:February2015FERCROEComplaintCase aee:AmerenIllinoisCompany0.0

Net Income Loss Available To Common Stockholders Basic

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value1469436417919168357239151-60288193102
Percentage of NetIncomeLossAvailableToCommonStockholdersBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax10.17.121.913.012.34.820.715.39.5-4.316.712.66.7

us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1469436417919168357239151
Percentage of NetIncomeLossAvailableToCommonStockholdersBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax10.17.121.913.012.34.820.715.39.5
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.0

Net Income Loss Attributable To Noncontrolling Interest

us-gaap:NetIncomeLossAttributableToNoncontrollingInterest



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value21212121212121212120-12213334
Percentage of NetIncomeLossAttributableToNoncontrollingInterest100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax0.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.0-0.10.10.10.10.20.10.20.2

us-gaap:StatementEquityComponents

us-gaap:NoncontrollingInterest



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-211-21211-212
Percentage of NetIncomeLossAttributableToNoncontrollingInterest-100.01100.0-100.0100.0100.01100.0-100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-0.10.8-0.10.10.10.8-0.10.10.1
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:NoncontrollingInterest0.00.00.00.00.00.00.00.00.0

Assets

us-gaap:Assets



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value292722893328546281032750927215269592663926079259452561725254248112469924134237932338523640234592315222884226762187621588211662104222385222762195221835234982298022899236452335623391233292351523702
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value124331218511946117241149411319110101077110471103451002298019569947492028999894489038656850084568381798377197640745474397366728872827227712772567213706471547406
Percentage of Assets42.542.141.841.741.841.640.840.440.239.939.138.838.638.438.137.838.237.736.936.737.037.036.535.836.135.433.233.133.233.430.831.031.730.530.230.631.5
Percentage of Assets42.542.141.841.741.841.640.840.440.239.939.138.838.638.438.137.838.237.736.936.737.037.036.535.836.135.433.233.133.233.430.831.031.730.530.230.631.5
Percentage of Assets aee:AmerenIllinoisCompany100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value14993149371486014698143711429114383143921404014043140681400513814140351388913649134431385113941137211355513541131791320312948129041323113131128671304312967126801254612757126381252712504
Percentage of Assets51.251.652.152.352.252.553.454.053.854.154.955.555.756.857.557.457.558.659.459.359.259.760.261.261.261.359.158.958.659.755.255.254.854.054.153.653.2
Percentage of Assets51.251.652.152.352.252.553.454.053.854.154.955.555.756.857.557.457.558.659.459.359.259.760.261.261.261.359.158.958.659.755.255.254.854.054.153.653.2
Percentage of Assets aee:UnionElectricCompany100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Liabilities

Liabilities And Stockholders Equity

us-gaap:LiabilitiesAndStockholdersEquity



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value292722893328546281032750927215269592663926079259452561725254248112469924134237932338523640234592315222884226762187621588211662104222385222762195221835234982298022899236452335623391233292351523702
Percentage of LiabilitiesAndStockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value124331218511946117241149411319110101077110471103451002298019569947492028999894489038656850084568381798377197640745474397366728872827227712772567213706471547406
Percentage of LiabilitiesAndStockholdersEquity42.542.141.841.741.841.640.840.440.239.939.138.838.638.438.137.838.237.736.936.737.037.036.535.836.135.433.233.133.233.430.831.031.730.530.230.631.5
Percentage of Assets42.542.141.841.741.841.640.840.440.239.939.138.838.638.438.137.838.237.736.936.737.037.036.535.836.135.433.233.133.233.430.831.031.730.530.230.631.5
Percentage of Assets aee:AmerenIllinoisCompany100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value14993149371486014698143711429114383143921404014043140681400513814140351388913649134431385113941137211355513541131791320312948129041323113131128671304312967126801254612757126381252712504
Percentage of LiabilitiesAndStockholdersEquity51.251.652.152.352.252.553.454.053.854.154.955.555.756.857.557.457.558.659.459.359.259.760.261.261.261.359.158.958.659.755.255.254.854.054.153.653.2
Percentage of Assets51.251.652.152.352.252.553.454.053.854.154.955.555.756.857.557.457.558.659.459.359.259.760.261.261.261.359.158.958.659.755.255.254.854.054.153.653.2
Percentage of Assets aee:UnionElectricCompany100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Stockholders Equity

us-gaap:StockholdersEquity



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-03-312010-12-312009-12-31
Value8085805980627791770576317656738672307184734571587064710371936922686969467014676467046713677465726513654465746374636566167874755574327919772577307856
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets27.627.928.227.728.028.028.427.727.727.728.728.328.528.829.829.129.429.429.929.229.329.631.030.430.831.129.428.629.030.333.532.932.533.533.132.933.1

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-31
Value43524132402139563894377436103547342533103225317031133034302129382925289728412742271326612602252725002448249324312416240124472434244124522502249325763072
Percentage of StockholdersEquity53.851.349.950.850.549.547.248.047.446.143.944.344.142.742.042.442.641.740.540.540.539.638.438.538.437.437.938.138.036.331.132.232.831.00.00.033.339.1
Percentage of Assets14.914.314.114.114.213.913.413.313.112.812.612.612.512.312.512.312.512.312.111.811.911.711.911.711.811.611.110.911.011.010.410.610.710.410.710.711.013.0
Percentage of Assets aee:AmerenIllinoisCompany35.033.933.733.733.933.332.832.932.732.032.232.332.532.032.832.632.732.532.832.332.131.832.632.732.732.833.533.033.233.033.934.233.634.035.434.834.80.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-31
Value43394349442542754268422943564237406940814117404340354090414739793956408241183954399440524121401139633993409639984004405441374001395840374235413041534057
Percentage of StockholdersEquity53.754.054.954.955.455.456.957.456.356.856.156.557.157.657.757.557.658.858.758.559.660.460.861.060.861.062.362.762.961.352.553.053.351.00.00.053.751.6
Percentage of Assets14.815.015.515.215.515.516.215.915.615.716.116.016.316.617.216.716.917.317.617.117.517.918.818.618.719.018.317.918.218.617.617.417.317.118.117.717.717.1
Percentage of Assets aee:UnionElectricCompany28.929.129.829.129.729.630.329.429.029.129.328.929.229.129.929.229.429.529.528.829.529.931.330.430.630.931.030.431.131.131.931.631.531.633.533.033.20.0

us-gaap:StatementEquityComponents

us-gaap:Parent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value80858059806277917705763176567386723071847103694667136544661679197730
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets27.627.928.227.728.028.028.427.727.727.728.829.429.631.130.333.532.9
Percentage of Assets us-gaap:Parent0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Assets Current

us-gaap:AssetsCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value146414311495151414221533164016851567161215811571145015931599159414581917198319911993204619421965184019723273340832962369240621542124229526802603271528942842
Percentage of AssetsCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets5.04.95.25.45.25.66.16.36.06.26.26.25.86.46.66.76.28.18.58.68.79.08.99.18.79.414.615.315.010.810.29.49.39.711.511.111.612.312.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value57161460961265767662957662667260260659268361758268676063270281184468560567763362571074774987490610611017110812011438
Percentage of AssetsCurrent39.042.940.740.446.244.138.434.239.941.738.138.640.842.938.636.547.139.631.935.340.741.335.330.836.832.119.120.822.731.636.342.150.044.341.346.149.7
Percentage of Assets2.02.12.12.22.42.52.32.22.42.62.42.42.42.82.62.42.93.22.73.03.53.73.12.83.23.02.83.23.43.43.73.94.64.34.75.16.1
Percentage of Assets aee:AmerenIllinoisCompany4.65.05.15.25.76.05.75.36.06.56.06.26.27.26.76.57.78.57.38.39.610.18.67.88.98.58.49.610.210.312.112.714.614.115.716.819.4

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value8588148829027518321042117290190596495078810041147974788118613251100964103910211117948959116511339791159119110238881134133911251275
Percentage of AssetsCurrent58.656.959.059.652.854.363.569.657.556.161.060.554.363.071.761.154.061.966.855.248.450.852.656.851.548.635.633.229.748.949.547.541.849.450.043.244.1
Percentage of Assets2.92.83.13.22.73.13.94.43.53.53.83.83.24.14.84.13.45.05.64.84.24.64.75.24.54.65.25.14.55.35.14.53.94.85.74.85.4
Percentage of Assets aee:UnionElectricCompany5.75.45.96.15.25.87.28.16.46.46.96.85.77.28.37.15.98.69.58.07.17.77.78.57.37.48.88.67.68.99.28.17.18.910.69.010.2

Cash And Cash Equivalents At Carrying Value

us-gaap:CashAndCashEquivalentsAtCarryingValue



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312008-12-312007-12-31
Value42162068161129301091089181313292722651346263016915016120929811720825552237857354560850636062292355
Percentage of CashAndCashEquivalentsAtCarryingValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.10.10.10.00.00.10.00.10.10.00.00.00.00.00.10.10.11.20.30.00.00.00.10.20.10.10.80.70.71.01.30.50.91.12.21.62.52.30.00.00.02.60.00.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-312008-12-31
Value60000000300000300710001121119893093601872111625350832228538330650
Percentage of CashAndCashEquivalentsAtCarryingValue14.30.00.00.00.00.00.00.010.00.00.00.00.00.016.70.00.024.30.00.00.020.07.74.33.83.30.665.357.80.031.251.389.98.222.266.988.759.146.975.749.254.3
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.30.00.00.00.00.00.00.00.00.00.40.40.00.40.30.80.10.51.12.21.40.00.01.30.0
Percentage of Assets aee:AmerenIllinoisCompany0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.80.00.00.00.00.00.00.00.00.01.31.30.01.30.82.60.31.63.50.04.30.00.00.00.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-31
Value390000017300000100199690111280110019114813203201356793820229191267
Percentage of CashAndCashEquivalentsAtCarryingValue7.156.20.00.00.00.00.058.610.00.00.00.00.00.05.60.00.068.295.80.016.720.07.760.90.03.359.212.70.670.844.30.01.478.868.220.96.637.147.918.042.9
Percentage of Assets0.00.00.00.00.00.00.00.10.00.00.00.00.00.00.00.00.00.80.30.00.00.00.00.10.00.00.40.10.00.70.60.00.00.91.50.30.20.90.00.01.1
Percentage of Assets aee:UnionElectricCompany0.00.10.00.00.00.00.00.10.00.00.00.00.00.00.00.00.01.40.50.00.00.00.00.20.00.00.80.10.01.11.00.00.01.62.80.60.01.60.00.00.0

Accounts Receivable Net Current

us-gaap:AccountsReceivableNetCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value456393478461517463605560514445507446457437543445428388508456524423467454553404469425479401523417446473575507517500424
Percentage of AccountsReceivableNetCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.61.41.71.61.91.72.22.12.01.72.01.81.81.82.21.91.81.62.22.02.31.92.12.12.61.92.11.92.21.82.21.81.92.02.52.22.22.11.8

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value268215222225315224251251298234219219270242259225262204229207304212192221328201185185274182197175228201194197230
Percentage of AccountsReceivableNetCurrent58.854.746.448.860.948.441.544.858.052.643.249.159.155.447.750.661.252.645.145.458.050.141.148.759.349.839.443.557.245.437.742.051.142.533.738.946.0
Percentage of Assets0.90.70.80.81.10.80.90.91.10.90.90.91.11.01.10.91.10.91.00.91.30.90.91.01.51.00.80.81.20.80.80.81.00.90.80.81.0
Percentage of Assets aee:AmerenIllinoisCompany2.21.81.91.92.72.02.32.32.82.32.22.22.82.62.82.52.92.32.62.43.62.52.42.94.32.72.52.53.82.52.72.53.12.82.72.83.1

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value174164243221189223331285205200274212175187272206150174260227202190261217218191270229202161263180170212308236217
Percentage of AccountsReceivableNetCurrent38.241.750.847.936.648.254.750.939.944.954.047.538.342.850.146.335.044.851.249.838.544.955.947.839.447.357.653.942.240.150.343.238.144.853.646.543.4
Percentage of Assets0.60.60.90.80.70.81.21.10.80.81.10.80.70.81.10.90.60.71.11.00.90.81.21.01.00.91.21.00.90.71.10.80.70.91.31.00.9
Percentage of Assets aee:UnionElectricCompany1.21.11.61.51.31.62.32.01.51.41.91.51.31.32.01.51.11.31.91.71.51.42.01.61.71.52.01.71.61.22.01.41.41.72.41.91.7

Inventory Net

us-gaap:InventoryNet



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value471494488433402483525475453522547512467527551515483538548500449524561491424526581511461704756686625712734654572707782
Percentage of InventoryNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.61.71.71.51.51.81.91.81.72.02.12.01.92.12.32.22.12.32.32.22.02.32.62.32.02.52.62.32.13.23.23.02.73.03.12.82.53.03.3

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value8012113297731251409570134151114861351591199415117412988177211138861742111418617320213796199239145198
Percentage of InventoryNet17.024.527.022.418.225.926.720.015.525.727.622.318.425.628.923.119.528.131.825.819.633.837.628.120.333.136.327.618.724.626.720.015.427.932.622.228.0
Percentage of Assets0.30.40.50.30.30.50.50.40.30.50.60.50.30.50.70.50.40.60.70.60.40.81.00.60.40.80.90.60.40.80.90.60.40.81.00.60.8
Percentage of Assets aee:AmerenIllinoisCompany0.61.01.10.80.61.11.30.90.71.31.51.20.91.41.71.31.11.72.01.51.02.12.61.81.12.32.81.91.22.42.81.91.32.83.42.02.7

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value391373356336329358385380383388396399381392392396389387374371361347350352338352370369375397402388365348337343341
Percentage of InventoryNet83.075.573.077.681.874.173.380.084.574.372.477.981.674.471.176.980.571.968.274.280.466.262.471.779.766.963.772.281.356.453.256.658.448.945.952.448.2
Percentage of Assets1.31.31.21.21.21.31.41.41.51.51.51.61.51.61.61.71.71.61.61.61.61.51.61.61.61.71.71.71.71.81.71.71.61.51.41.51.5
Percentage of Assets aee:UnionElectricCompany2.62.52.42.32.32.52.72.62.72.82.82.82.82.82.82.92.92.82.72.72.72.62.72.72.62.72.82.82.93.03.13.12.92.72.72.72.7

Other Assets Current

us-gaap:OtherAssetsCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value1271181069070638372849896971059876686388103959186666870851081046095989913413213210410010998
Percentage of OtherAssetsCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.40.40.40.30.30.20.30.30.30.40.40.40.40.40.30.30.30.40.40.40.40.40.30.30.30.40.50.50.30.40.40.40.60.60.60.40.40.50.4

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value31292624151618101215181116251711131516101315171420263329364747101165108109106
Percentage of OtherAssetsCurrent24.424.624.526.721.425.421.713.914.315.318.811.315.225.522.416.220.617.015.510.514.317.425.820.628.630.630.627.960.049.548.010.18.249.281.8104.897.2
Percentage of Assets0.10.10.10.10.10.10.10.00.00.10.10.00.10.10.10.00.10.10.10.00.10.10.10.10.10.10.10.10.20.20.20.00.00.30.50.50.5
Percentage of Assets aee:AmerenIllinoisCompany0.20.20.20.20.10.10.20.10.10.10.20.10.20.30.20.10.10.20.20.10.20.20.20.20.30.30.40.40.50.60.70.10.20.91.51.51.4

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value966666523226404248504343454937332941578977924082507165100516963662482681420
Percentage of OtherAssetsCurrent75.655.962.357.845.741.348.258.357.151.044.844.342.950.048.748.546.046.655.393.784.6107.060.6120.671.483.560.296.285.072.664.366.717.962.151.513.518.3
Percentage of Assets0.30.20.20.20.10.10.10.20.20.20.20.20.20.20.20.10.10.20.20.40.30.40.20.40.20.30.30.40.20.30.30.30.10.30.30.10.1
Percentage of Assets aee:UnionElectricCompany0.60.40.40.40.20.20.30.30.30.40.30.30.30.30.30.20.20.30.40.60.60.70.30.60.40.60.50.80.40.50.50.50.20.60.50.10.2

Property Plant And Equipment Gross

Accumulated Depreciation Depletion And Amortization Property Plant And Equipment

Property Plant And Equipment Net

us-gaap:PropertyPlantAndEquipmentNet



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value246782437623894234792304422810223792199821666214662090620589202982011319647193241900018799183071798617700174241699116726164251620515834156011540816096178331769017535181271787317945178881785317610
Percentage of PropertyPlantAndEquipmentNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets84.384.283.783.583.883.883.082.683.182.781.681.581.881.481.481.281.279.578.077.777.376.877.777.577.677.070.770.070.273.775.977.076.676.776.576.776.775.974.3

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value102801008398199585934791988969871684638293798777807596746972857121695668486615641662726165603058825731558953695216511750524948486948044770469946574576
Percentage of PropertyPlantAndEquipmentNet41.741.441.140.840.640.340.139.639.138.638.237.837.437.137.136.936.636.436.135.735.435.435.535.234.934.533.933.433.231.427.727.527.426.326.326.025.6
Percentage of Assets35.134.834.434.134.033.833.332.732.532.031.230.830.630.230.229.929.729.028.227.727.427.227.627.227.126.624.023.423.323.121.121.221.020.220.119.919.5
Percentage of Assets aee:AmerenIllinoisCompany82.782.782.281.881.381.381.580.980.880.279.779.479.478.879.279.177.876.976.475.574.273.675.576.275.075.072.270.870.269.468.568.366.266.166.565.161.8

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value127311263512452123151215912103119331183511768117511153811497114711147811294112421118111183110411101710959108671066010599104991045210337102641015210161100921003899769958979698629775
Percentage of PropertyPlantAndEquipmentNet51.651.852.152.552.853.153.353.854.354.755.255.856.557.157.558.258.859.560.361.361.962.462.763.463.964.565.365.865.963.156.656.756.954.954.855.054.8
Percentage of Assets43.543.743.643.844.244.544.344.445.145.345.045.546.246.546.847.247.847.347.147.647.947.948.749.149.649.746.246.146.246.542.943.743.642.141.942.241.6
Percentage of Assets aee:UnionElectricCompany84.984.683.883.884.684.783.082.283.883.782.082.183.081.881.382.483.280.779.280.380.880.380.980.381.181.078.178.278.977.977.879.279.578.177.578.778.2

Goodwill

us-gaap:Goodwill



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value411411411411411411411411411411411411411411411411411411411411411411411411411411411411411411411411411411411411411411831
Percentage of Goodwill100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.41.41.41.51.51.51.51.51.61.61.61.61.71.71.71.71.81.71.81.81.81.81.91.91.92.01.81.81.91.91.71.81.81.71.81.81.81.73.5

Intangible Assets Net Excluding Goodwill

Other Assets Noncurrent

us-gaap:OtherAssetsNoncurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value885876780741744650647626532522538526532538566552573575646649645664724731719698660654665749772776773845843848738754655
Percentage of OtherAssetsNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets3.03.02.72.62.72.42.42.32.02.02.12.12.12.22.32.32.52.42.82.82.82.93.33.43.43.32.92.93.03.43.33.43.43.63.63.63.23.22.8

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value40038331129330327525824615914710197959598991141137678797814514411512081838897112117115211214193162
Percentage of OtherAssetsNoncurrent45.243.739.939.540.742.339.939.329.928.218.818.417.917.717.317.919.919.711.812.012.211.720.019.716.017.212.312.713.213.014.515.114.925.025.422.821.5
Percentage of Assets1.41.31.11.01.11.01.00.90.60.60.40.40.40.40.40.40.50.50.30.30.30.30.70.70.50.60.40.40.40.40.50.50.50.90.90.80.7
Percentage of Assets aee:AmerenIllinoisCompany3.23.12.62.52.62.42.32.31.51.41.01.01.01.01.11.11.31.30.90.90.90.91.81.91.51.61.11.11.21.31.51.61.62.93.02.72.2

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value357356370355356306305304293288318317314327335315316321395389387391410416442443443444451449452447441446474489421
Percentage of OtherAssetsNoncurrent40.340.647.447.947.847.147.148.655.155.259.160.359.060.859.257.155.155.861.159.960.058.956.656.961.563.567.167.967.859.958.557.657.152.856.257.755.8
Percentage of Assets1.21.21.31.31.31.11.11.11.11.11.21.31.31.31.41.31.41.41.71.71.71.71.91.92.12.12.02.02.12.11.91.91.91.92.02.11.8
Percentage of Assets aee:UnionElectricCompany2.42.42.52.42.52.12.12.12.12.12.32.32.32.32.42.32.42.32.82.82.92.93.13.23.43.43.33.43.53.43.53.53.53.53.83.93.4

Liabilities Current

us-gaap:LiabilitiesCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value236725052285275223922687258027113345294025812765276226742291243018392093248925562520224921192312272524613228328625771698154616031614178518481727183718881711
Percentage of LiabilitiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets8.18.78.09.88.79.99.610.212.811.310.110.911.110.89.510.27.98.910.611.011.09.99.710.712.911.714.414.811.77.86.67.07.07.57.97.47.98.07.2

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value80784497689780379611821057137513581266121196297181174271375285475766070085477910027718478237927976827648208587538381015
Percentage of LiabilitiesCurrent34.133.742.732.633.629.645.839.041.146.249.143.834.836.335.430.538.835.934.329.626.231.140.333.736.831.326.225.030.746.944.147.750.848.140.748.553.8
Percentage of Assets2.82.93.43.22.92.94.44.05.35.24.94.83.93.93.43.13.03.23.63.32.93.13.93.64.73.73.83.73.63.72.93.33.63.63.23.64.3
Percentage of Assets aee:AmerenIllinoisCompany6.56.98.27.77.07.010.79.813.113.112.612.410.110.28.88.28.08.49.98.97.88.410.710.113.110.311.411.210.910.99.410.711.311.910.711.713.7

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value7941126125512429851402103512211495116410569149641162107110936659779849361088903781946116710471069951656799795830778942745624700
Percentage of LiabilitiesCurrent33.545.054.945.141.252.240.145.044.739.640.933.134.943.546.745.036.246.739.536.643.240.236.940.942.842.533.128.925.547.151.451.848.252.840.336.137.1
Percentage of Assets2.73.94.44.43.65.23.84.65.74.54.13.63.94.74.44.62.84.14.24.04.84.03.64.45.55.04.84.33.03.73.43.63.44.03.22.73.0
Percentage of Assets aee:UnionElectricCompany5.37.58.48.56.99.87.28.510.68.37.56.57.08.37.78.04.97.17.16.88.06.75.97.29.08.18.17.25.16.16.16.56.27.45.95.05.6

Long Term Debt Current

us-gaap:LongTermDebtCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value35744233633633658064984711708417775786816814314311353953953953801201191196485348848843553552061791791791785155155204
Percentage of LongTermDebtCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.21.51.21.21.22.12.43.24.53.23.02.32.72.81.81.80.61.71.71.71.70.50.50.63.12.53.94.01.61.60.90.80.80.80.80.00.70.70.9

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-31
Value79233633633658033653471338438318543143143143162662662663801201191192231093093092052052051781781781785-5-4
Percentage of LongTermDebtCurrent2.020.8100.0100.0100.0100.051.863.060.945.749.332.063.363.3100.0100.04.467.367.367.3100.0100.0100.0100.034.420.435.035.057.757.799.599.499.499.4100.0100.0-3.2-2.0
Percentage of Assets0.00.31.21.21.22.11.22.02.71.51.50.71.71.71.81.80.01.11.11.11.70.50.50.61.10.51.41.40.90.90.90.80.80.80.80.0-0.0-0.0
Percentage of Assets aee:UnionElectricCompany0.00.62.32.32.34.12.33.75.12.72.71.33.13.13.13.20.01.91.91.92.80.90.90.91.70.82.32.41.61.61.61.41.41.41.40.0-0.00.0

Accounts Payable And Accrued Liabilities Current

us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value544874598593522817591565497902548522460805513499429777525486434711466575559806414428341625458479366693410482401651694
Percentage of AccountsPayableAndAccruedLiabilitiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.93.02.12.11.93.02.22.11.93.52.12.11.93.32.12.11.83.32.22.11.93.12.12.72.63.81.81.91.62.91.92.11.62.91.82.11.72.82.9

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value246299247272242302275291243337247236198264214212180249251229193207212209230243189184151146148171115133135185182
Percentage of AccountsPayableAndAccruedLiabilitiesCurrent45.234.241.345.946.437.046.551.548.937.445.145.243.032.841.742.542.032.047.847.144.529.145.536.341.130.145.743.044.323.432.335.731.419.232.938.428.0
Percentage of Assets0.81.00.91.00.91.11.01.10.91.31.00.90.81.10.90.90.81.11.11.00.80.91.01.01.11.20.80.80.70.70.60.70.50.60.60.80.8
Percentage of Assets aee:AmerenIllinoisCompany2.02.52.12.32.12.72.52.72.33.32.52.42.12.82.32.42.02.82.92.72.32.52.72.73.03.32.52.52.12.02.02.41.61.81.92.62.5

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value238465261240224428246226203475226208191444209204174417187183182405189195183387186198153345187168142414160179326
Percentage of AccountsPayableAndAccruedLiabilitiesCurrent43.853.243.640.542.952.441.640.040.852.741.239.841.555.240.740.940.653.735.637.741.957.040.633.932.748.044.946.344.955.240.835.138.859.739.037.150.1
Percentage of Assets0.81.60.90.90.81.60.90.80.81.80.90.80.81.80.90.90.71.80.80.80.81.80.90.90.91.80.80.90.71.60.80.70.61.80.70.81.4
Percentage of Assets aee:UnionElectricCompany1.63.11.81.61.63.01.71.61.43.41.61.51.43.21.51.51.33.01.31.31.33.01.41.51.43.01.41.51.22.61.41.31.13.21.31.42.6

Taxes Payable Current

dei:LegalEntity

us-gaap:TaxesPayableCurrent

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value64241481106227138110643014811363301491136431273151693220015725222028810766281331031137413113476
Percentage of TaxesPayableCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.20.10.50.40.20.10.50.40.20.10.60.40.30.10.60.50.30.11.20.70.30.10.90.71.21.01.30.50.30.10.60.40.50.30.60.60.3
Percentage of Assets aee:UnionElectricCompany0.40.21.00.70.40.21.00.80.50.21.10.80.50.21.10.80.50.22.01.10.50.21.51.21.91.72.20.80.50.21.00.80.90.61.01.10.6

Other Liabilities Current

us-gaap:OtherLiabilitiesCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value662585522668301282317298285326318298280248252270305379404413437434350350344194190178163188193221237207251262294283337
Percentage of OtherLiabilitiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.32.01.82.41.11.01.21.11.11.31.21.21.11.01.01.11.31.61.71.81.91.91.61.61.60.90.80.80.70.90.81.01.00.91.11.11.31.21.4

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value1952071761841291301611501411771531288894998882114908010012414812115311411479639262865792587790
Percentage of OtherLiabilitiesCurrent29.535.433.727.542.946.150.850.349.554.348.143.031.437.939.332.626.930.122.319.422.928.642.334.644.558.860.044.438.748.932.138.924.144.423.129.431.8
Percentage of Assets0.70.70.60.70.50.50.60.60.50.70.60.50.40.40.40.40.40.50.40.30.40.50.70.60.70.50.50.40.30.40.30.40.20.40.20.30.4
Percentage of Assets aee:AmerenIllinoisCompany1.61.71.51.61.11.11.51.41.31.71.51.30.91.01.11.00.91.31.00.91.21.51.91.62.01.51.51.10.91.30.91.20.81.30.81.11.2

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value128221240210128123115107991031181301281231161391321201161241141179910187829790867711413012084829089
Percentage of OtherLiabilitiesCurrent19.337.846.031.442.543.636.335.934.731.637.143.645.749.646.051.543.331.728.730.026.127.028.328.925.342.351.150.652.841.059.158.850.640.632.734.431.4
Percentage of Assets0.40.80.80.70.50.50.40.40.40.40.50.50.50.50.50.60.60.50.50.50.50.50.50.50.40.40.40.40.40.40.50.60.50.40.40.40.4
Percentage of Assets aee:UnionElectricCompany0.91.51.61.40.90.90.80.70.70.70.80.90.90.90.81.01.00.90.80.90.80.90.80.80.70.60.70.70.70.60.91.01.00.70.60.70.7

us-gaap:BalanceSheetLocation

aee:AssetRetirementObligationBalance



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-312015-12-31
Value53532323232366661515155
Percentage of OtherLiabilitiesCurrent8.09.14.43.47.68.21.92.02.11.84.75.06.01.3
Percentage of Assets0.20.20.10.10.10.10.00.00.00.00.10.10.10.0
Percentage of Assets aee:AssetRetirementObligationBalance0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:BalanceSheetLocation, dei:LegalEntity

aee:AssetRetirementObligationBalance, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value5353232323
Percentage of OtherLiabilitiesCurrent8.09.14.43.48.2
Percentage of Assets0.20.20.10.10.1
Percentage of Assets aee:AssetRetirementObligationBalance aee:UnionElectricCompany0.00.00.00.00.0

Long Term Debt

Long Term Debt Noncurrent

us-gaap:LongTermDebtNoncurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value937889158651822282217859761476136766709469226821659765956607660568816880598159815860612058255825522655045274527458036626678166786677667766826854685368537111
Percentage of LongTermDebtNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets32.030.830.329.329.928.928.228.625.927.327.027.026.626.727.427.829.429.125.525.825.627.026.627.024.726.223.623.726.430.328.929.129.228.228.629.329.429.130.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value3575357532793296329632962801280023732373219621952338233823442343234323422112211222412241194019401692185615771577157715771727165716571657165816581657
Percentage of LongTermDebtNoncurrent38.140.137.940.140.141.936.836.835.133.531.732.235.435.535.535.534.134.035.335.338.236.633.333.332.433.729.929.927.223.825.524.824.824.824.824.224.2
Percentage of Assets12.212.411.511.712.012.110.410.59.19.18.68.79.49.59.79.810.09.99.09.19.89.98.99.08.08.87.07.17.27.27.37.27.27.07.17.17.0
Percentage of Assets aee:AmerenIllinoisCompany28.829.327.428.128.729.125.426.022.722.921.922.424.424.725.526.026.226.324.424.826.526.724.325.122.124.921.221.421.621.723.923.222.823.023.523.222.4

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-31
Value45604098377937803780341836683668324935773584378135643563356935683845384438693869361938793885388535353648369736973801380138063772377237723777394939494018
Percentage of LongTermDebtNoncurrent48.646.043.746.046.043.548.248.248.050.451.855.454.054.054.054.055.955.964.764.761.863.466.766.767.666.370.170.165.557.456.156.556.556.556.557.657.656.5
Percentage of Assets15.614.213.213.513.712.613.613.812.513.814.015.014.414.414.815.016.416.316.516.715.817.117.818.016.717.316.516.617.317.416.216.416.516.016.216.916.817.0
Percentage of Assets aee:UnionElectricCompany30.427.425.425.726.323.925.525.523.125.525.527.025.825.425.726.128.627.827.828.226.728.629.529.427.328.327.928.229.529.129.429.730.129.629.931.531.60.0

Deferred Tax Liabilities Noncurrent

Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value397401522539558558529545541545711758768769499537581580666689708705400463480466104211401113117811521251135713449221067105710451165
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.41.41.81.92.02.12.02.02.12.12.83.03.13.12.12.32.52.52.83.03.13.11.82.12.32.24.75.15.15.44.95.45.95.73.94.64.54.44.9

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value212214261274281280284292285285322350345346262284271271282292278277189215200197376416396406444458499495328446413
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent53.453.450.050.850.450.253.753.652.752.345.346.244.945.052.552.946.646.742.342.439.339.347.246.441.742.336.136.535.634.538.536.636.836.835.641.839.5
Percentage of Assets0.70.70.91.01.01.01.11.11.11.11.31.41.41.41.11.21.21.11.21.31.21.20.91.00.90.91.71.91.81.91.92.02.22.11.41.91.8
Percentage of Assets aee:AmerenIllinoisCompany1.71.82.22.32.42.52.62.72.72.83.23.63.63.72.83.23.03.03.33.43.33.32.42.82.62.65.15.65.45.66.16.46.96.94.66.25.6

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value139141211214227228204209212213274287292291183195236234267275277274147172198189423465452461432442498491352371369
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent35.035.240.439.740.740.938.638.339.239.138.537.938.037.836.736.340.640.340.139.939.138.936.837.141.240.640.640.840.639.137.535.336.736.538.234.835.3
Percentage of Assets0.50.50.70.80.80.80.80.80.80.81.11.11.21.20.80.81.01.01.11.21.21.20.70.80.90.91.92.12.12.11.81.92.22.11.51.61.6
Percentage of Assets aee:UnionElectricCompany0.90.91.41.51.61.61.41.51.51.51.92.02.12.11.31.41.81.71.92.02.02.01.11.31.51.53.23.53.53.53.33.54.03.82.83.03.0

Minority Interest

us-gaap:MinorityInterest



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-31
Value142142142142142142142142142142142142142142142142142142142142142142142142142142151151151151152145147149155155155154155206206204
Percentage of MinorityInterest100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.50.50.50.50.50.50.50.50.50.50.60.60.60.60.60.60.60.60.60.60.60.60.60.70.70.70.70.70.70.70.60.60.60.60.70.70.70.70.00.00.00.9

Other Liabilities Noncurrent

us-gaap:OtherLiabilitiesNoncurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value482467466464422408409431445460469477481477481490530531530524524514522524554622534585593668563564567447469481553615491
Percentage of OtherLiabilitiesNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.61.61.61.71.51.51.51.61.71.81.81.91.91.92.02.12.32.22.32.32.32.32.42.42.63.02.42.62.73.12.42.52.51.92.02.12.42.62.1

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value277260260238203204207218230234229228236222212207236222224221216189165152173166152149146399276276291183231282460
Percentage of OtherLiabilitiesNoncurrent57.555.755.851.348.150.050.650.651.750.948.847.849.146.544.142.244.541.842.342.241.236.831.629.031.226.728.525.524.659.749.048.951.340.949.358.674.8
Percentage of Assets0.90.90.90.80.70.70.80.80.90.90.90.91.00.90.90.91.00.91.01.00.90.80.80.70.80.80.70.70.71.81.21.21.30.81.01.22.0
Percentage of Assets aee:AmerenIllinoisCompany2.22.12.22.01.81.81.92.02.22.32.32.32.52.32.32.32.62.52.62.62.62.32.12.02.32.22.02.02.05.53.83.94.02.53.33.96.2

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value5240444440165713121316161921242728303032304442435249150146158161153150149172176218
Percentage of OtherLiabilitiesNoncurrent10.88.69.49.59.53.91.21.62.92.62.83.43.34.04.44.95.15.35.75.76.15.88.48.07.88.49.225.624.623.728.627.126.533.336.736.635.4
Percentage of Assets0.20.10.20.20.10.10.00.00.00.00.10.10.10.10.10.10.10.10.10.10.10.10.20.20.20.20.20.70.70.70.70.70.70.60.70.80.9
Percentage of Assets aee:UnionElectricCompany0.30.30.30.30.30.10.00.00.10.10.10.10.10.10.20.20.20.20.20.20.20.20.30.30.30.40.41.11.11.21.21.21.21.21.41.41.7

Stockholders Equity

us-gaap:StockholdersEquity



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-03-312010-12-312009-12-31
Value8085805980627791770576317656738672307184734571587064710371936922686969467014676467046713677465726513654465746374636566167874755574327919772577307856
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets27.627.928.227.728.028.028.427.727.727.728.728.328.528.829.829.129.429.429.929.229.329.631.030.430.831.129.428.629.030.333.532.932.533.533.132.933.1

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-31
Value43524132402139563894377436103547342533103225317031133034302129382925289728412742271326612602252725002448249324312416240124472434244124522502249325763072
Percentage of StockholdersEquity53.851.349.950.850.549.547.248.047.446.143.944.344.142.742.042.442.641.740.540.540.539.638.438.538.437.437.938.138.036.331.132.232.831.00.00.033.339.1
Percentage of Assets14.914.314.114.114.213.913.413.313.112.812.612.612.512.312.512.312.512.312.111.811.911.711.911.711.811.611.110.911.011.010.410.610.710.410.710.711.013.0
Percentage of Assets aee:AmerenIllinoisCompany35.033.933.733.733.933.332.832.932.732.032.232.332.532.032.832.632.732.532.832.332.131.832.632.732.732.833.533.033.233.033.934.233.634.035.434.834.80.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-31
Value43394349442542754268422943564237406940814117404340354090414739793956408241183954399440524121401139633993409639984004405441374001395840374235413041534057
Percentage of StockholdersEquity53.754.054.954.955.455.456.957.456.356.856.156.557.157.657.757.557.658.858.758.559.660.460.861.060.861.062.362.762.961.352.553.053.351.00.00.053.751.6
Percentage of Assets14.815.015.515.215.515.516.215.915.615.716.116.016.316.617.216.716.917.317.617.117.517.918.818.618.719.018.317.918.218.617.617.417.317.118.117.717.717.1
Percentage of Assets aee:UnionElectricCompany28.929.129.829.129.729.630.329.429.029.129.328.929.229.129.929.229.429.529.528.829.529.931.330.430.630.931.030.431.131.131.931.631.531.633.533.033.20.0

us-gaap:StatementEquityComponents

us-gaap:Parent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value80858059806277917705763176567386723071847103694667136544661679197730
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets27.627.928.227.728.028.028.427.727.727.728.829.429.631.130.333.532.9
Percentage of Assets us-gaap:Parent0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Common Stock Value

Retained Earnings Accumulated Deficit

us-gaap:RetainedEarningsAccumulatedDeficit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value240423802408216120992024207318271699166018301649156315681643137613331331140511611111110311549579069079677627641006225919831869236924402248220322252455
Percentage of RetainedEarningsAccumulatedDeficit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets8.28.28.47.77.67.47.76.96.56.47.16.56.36.36.85.85.75.66.05.04.94.95.34.44.34.34.33.43.54.69.68.68.210.010.49.69.49.510.4

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value2002188217861721165915391455139213301235115811031046967952868854825793694664611566491463410454392376360406392398408471461542
Percentage of RetainedEarningsAccumulatedDeficit83.379.174.279.679.076.070.276.278.374.463.366.966.961.757.963.164.162.056.459.859.855.449.051.351.145.246.951.449.235.818.019.821.317.219.320.524.4
Percentage of Assets6.86.56.36.16.05.75.45.25.14.84.54.44.23.93.93.63.73.53.43.02.92.72.62.32.21.92.01.81.71.61.71.71.71.72.02.02.3
Percentage of Assets aee:AmerenIllinoisCompany16.115.415.014.714.413.613.212.912.711.911.611.310.910.210.39.69.59.39.28.27.97.37.16.46.15.56.15.35.24.95.65.55.55.76.76.47.3

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value1721173119311781177417351907178816201632169816241616167117321566154316691743157916191892197018601812184219491851185719071991185518121891208919842007
Percentage of RetainedEarningsAccumulatedDeficit71.672.780.282.484.585.792.097.995.498.392.898.5103.4106.6105.4113.8115.8125.4124.1136.0145.7171.5170.7194.4200.0203.1201.6242.9243.1189.688.193.597.079.885.688.390.2
Percentage of Assets5.96.06.86.36.46.47.16.76.26.36.66.46.56.87.26.66.67.17.46.87.18.39.08.68.68.88.78.38.58.78.58.17.98.08.98.58.5
Percentage of Assets aee:UnionElectricCompany11.511.613.012.112.312.113.312.411.511.612.111.611.711.912.511.511.512.012.511.511.914.014.914.114.014.314.714.114.414.615.414.614.414.816.515.816.1

Accumulated Other Comprehensive Income Loss Net Of Tax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value-16-17-21-21-21-22-17-19-17-18-21-21-23-23-2-1-5-3-5-5-9-96633-19-9-15-82-30-35-50-25-21-20-17-13
Percentage of AccumulatedOtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.00.00.00.00.0-0.1-0.0-0.1-0.00.0-0.1-0.2-0.2-0.1-0.1-0.1-0.1-0.1

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value290502789492387484866562258461780532331564796414349489761469298348549239379556392554380
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax20.138.147.635.724.934.150.236.016.332.945.334.621.941.642.829.024.337.441.533.519.225.432.915.025.727.823.629.119.6

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value232256254225227143229157130187253163212176245153229222155132254499519227181289315
Percentage of NetCashProvidedByUsedInOperatingActivities80.051.032.245.758.729.526.427.950.440.632.430.664.031.230.837.065.645.420.428.185.214.117.380.371.514.673.756.9
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax16.119.515.316.314.610.113.310.08.213.314.710.614.013.013.210.716.017.08.59.416.33.65.712.018.44.017.416.5
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany32.139.145.041.129.821.240.627.217.127.744.128.330.229.636.228.233.840.123.725.734.17.716.624.839.612.539.939.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value412274792091522995493367619742330393281524195169207594289157290448966842112180
Percentage of NetCashProvidedByUsedInOperatingActivities14.145.260.742.539.361.863.459.829.542.754.257.028.149.865.847.148.442.378.161.652.783.381.640.217.975.730.914.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax2.817.228.915.29.821.131.821.54.814.124.619.76.120.728.213.711.815.832.420.610.121.226.86.04.621.07.34.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany6.036.145.226.220.141.948.635.29.628.237.932.411.837.545.022.522.827.550.732.719.639.240.811.88.539.617.510.4

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value-684-637-644-587-567-617-590-532-597-620-526-520-539-590-516-525-510-614-487-436-439-505-442-313-303-373-326-250-317
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-47.5-48.4-38.8-42.6-36.4-43.5-34.2-34.0-37.7-44.2-30.5-33.8-35.6-43.5-27.8-36.8-35.6-46.9-26.6-31.1-28.2-36.9-26.5-19.6-20.5-18.6-19.7-13.1-16.3

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value-323-302-345-291-267-311-338-299-300-316-274-253-227-239-241-169-269-298-240-168-207-201-195-214-138-57-86-19
Percentage of NetCashProvidedByUsedInInvestingActivities47.247.453.649.647.150.457.356.250.351.052.148.742.140.546.732.252.748.549.338.547.239.844.168.445.515.326.47.6
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-22.4-22.9-20.8-21.1-17.2-21.9-19.6-19.1-18.9-22.5-15.9-16.5-15.0-17.6-13.0-11.8-18.8-22.8-13.1-12.0-13.3-14.7-11.7-13.4-9.4-2.8-5.2-1.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany-44.7-46.2-61.2-53.2-35.0-46.1-59.9-51.7-39.5-46.9-47.7-43.9-32.3-40.2-35.7-31.2-39.7-53.9-36.6-32.7-27.8-31.8-34.1-27.6-20.2-8.8-11.9-2.4

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value-328-310-264-257-264-241-192-278-265-230-202-185-68-210-370-184-17015-411-159-169-244-180-204-129-177-218-156
Percentage of NetCashProvidedByUsedInInvestingActivities48.048.741.043.846.639.132.552.344.437.138.435.612.635.671.735.033.3-2.484.436.538.548.340.765.242.647.566.962.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-22.8-23.6-15.9-18.6-17.0-17.0-11.1-17.8-16.7-16.4-11.7-12.0-4.5-15.5-19.9-12.9-11.91.1-22.4-11.3-10.9-17.8-10.8-12.8-8.7-8.8-13.1-8.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany-48.2-49.4-24.9-32.2-34.8-33.8-17.0-29.1-33.5-32.9-18.1-19.8-8.6-28.0-31.8-21.2-22.92.0-35.1-18.0-21.1-33.0-16.4-25.0-16.2-16.6-31.5-20.2

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value421156-11299191148-280-23360160-255-1020717-275111-118345-204-37142149-14070-99-2-113-276-325
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax29.211.9-6.87.212.310.4-16.2-1.522.711.4-14.8-0.713.71.3-14.87.8-8.226.4-11.1-2.69.110.9-8.44.4-6.7-0.1-6.8-14.5-16.8

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value10654109725317712314718112921901560-116-311478536-481529922-409-37-110
Percentage of NetCashProvidedByUsedInFinancingActivities25.234.6-97.372.727.7119.6-43.9-639.150.380.6-8.2-900.07.2352.90.414.426.342.6-41.7-97.3-33.8102.0-70.731.440.4-450.032.739.9
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax7.44.16.65.23.412.57.19.411.49.21.25.91.04.4-0.11.1-2.211.24.62.6-3.111.15.91.4-2.70.4-2.2-5.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany14.78.319.313.27.026.321.825.423.819.13.715.62.110.1-0.13.0-4.626.613.07.0-6.424.017.32.8-5.81.4-5.1-13.6

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value272108-21449116-57-375-4319233-221-118-25-72-153-11-198-92-114-13112-46-295107-86-112-101-88
Percentage of NetCashProvidedByUsedInFinancingActivities64.669.2191.149.560.7-38.5133.9187.053.320.686.71180.0-12.1-423.555.6-9.9167.8-26.755.9354.18.5-30.9210.7152.986.95600.089.431.9
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax18.98.2-12.93.67.5-4.0-21.8-2.812.12.4-12.8-7.7-1.7-5.3-8.2-0.8-13.8-7.0-6.2-9.40.8-3.4-17.76.7-5.8-5.6-6.1-4.6
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany40.017.2-20.26.115.3-8.0-33.2-4.524.24.7-19.8-12.6-3.2-9.6-13.1-1.3-26.7-12.2-9.7-14.81.5-6.2-26.913.1-10.8-10.5-14.6-11.4

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value290502789492387484866562258461780532331564796414349489761469298348549239379556392554380
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax20.138.147.635.724.934.150.236.016.332.945.334.621.941.642.829.024.337.441.533.519.225.432.915.025.727.823.629.119.6

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value232256254225227143229157130187253163212176245153229222155132254499519227181289315
Percentage of NetCashProvidedByUsedInOperatingActivities80.051.032.245.758.729.526.427.950.440.632.430.664.031.230.837.065.645.420.428.185.214.117.380.371.514.673.756.9
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax16.119.515.316.314.610.113.310.08.213.314.710.614.013.013.210.716.017.08.59.416.33.65.712.018.44.017.416.5
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany32.139.145.041.129.821.240.627.217.127.744.128.330.229.636.228.233.840.123.725.734.17.716.624.839.612.539.939.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value412274792091522995493367619742330393281524195169207594289157290448966842112180
Percentage of NetCashProvidedByUsedInOperatingActivities14.145.260.742.539.361.863.459.829.542.754.257.028.149.865.847.148.442.378.161.652.783.381.640.217.975.730.914.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax2.817.228.915.29.821.131.821.54.814.124.619.76.120.728.213.711.815.832.420.610.121.226.86.04.621.07.34.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany6.036.145.226.220.141.948.635.29.628.237.932.411.837.545.022.522.827.550.732.719.639.240.811.88.539.617.510.4

Net Income Loss

dei:LegalEntity

us-gaap:NetIncomeLoss

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value12096656212084636295775557792711946603398325446752954227732321271332826983834
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax8.37.33.94.57.75.93.74.06.05.53.23.75.22.06.43.24.22.55.32.33.53.44.52.03.41.74.72.32.20.83.52.01.71.64.32.11.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany16.614.711.511.315.712.511.210.712.511.49.69.911.24.517.68.58.96.015.06.27.27.313.15.67.03.914.16.24.72.011.05.93.94.313.26.14.2

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value-10-2030010739-2229416838-36234120572429315112406242-5223127483323985411623714422-141919122
Percentage of NetIncomeLoss-8.3-20.8461.5172.632.5-26.2466.7271.040.0-46.8425.5210.56.325.9203.4202.225.033.3244.9193.877.8-10.9297.3437.988.9150.0310.4265.6128.1133.3333.8436.478.6-53.8194.9239.564.7
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-0.7-1.518.17.82.5-1.617.110.72.4-2.613.67.80.30.513.06.51.00.813.14.42.7-0.413.48.93.02.514.66.12.81.111.88.71.3-0.98.45.11.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany-1.5-3.228.313.45.1-3.126.017.64.8-5.221.012.80.60.920.810.72.01.520.57.05.2-0.720.314.15.94.321.99.65.22.422.317.13.2-2.117.111.12.8

us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, aee:AmerenIllinoisElectricDistribution



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value37413237363535333337313330
Percentage of NetIncomeLoss30.842.749.259.730.041.755.653.234.748.156.457.938.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax2.63.11.92.72.32.52.02.12.12.61.82.12.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:AmerenIllinoisElectricDistribution9.50.08.210.39.30.08.98.58.20.07.78.50.0

us-gaap:OperatingSegments, aee:AmerenIllinoisGas



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value5527-1157210742202533
Percentage of NetIncomeLoss45.828.1-1.51.647.525.00.011.344.226.03.68.841.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax3.82.1-0.10.13.71.50.00.42.61.40.10.32.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:AmerenIllinoisGas20.30.0-0.90.717.80.00.04.913.50.01.83.70.0

us-gaap:OperatingSegments, aee:AmerenTransmission



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value47465342444348363734383434
Percentage of NetIncomeLoss39.247.981.567.736.751.276.258.138.944.269.159.643.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax3.33.53.23.02.83.02.82.32.32.42.22.22.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:AmerenTransmission38.20.041.438.538.60.042.535.035.60.031.932.40.0

us-gaap:OperatingSegments, aee:OtherSegment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value170-20-815-9-20-51-115-1710
Percentage of NetIncomeLoss14.20.0-30.8-12.912.5-10.7-31.7-8.11.1-149.4-30.91.80.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax1.20.0-1.2-0.61.0-0.6-1.2-0.30.1-8.2-1.00.10.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:OtherSegment0.00.00.00.00.00.00.00.00.00.0850.050.00.0

us-gaap:OperatingSegments, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-03-31
Value-10-2030010739-2229416838-362345
Percentage of NetIncomeLoss-8.3-20.8461.5172.632.5-26.2466.7271.040.0-46.8425.56.3
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-0.7-1.518.17.82.5-1.617.110.72.4-2.613.60.3
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:UnionElectricCompany-1.50.028.313.45.10.026.017.64.80.021.00.0

us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments, dei:LegalEntity

us-gaap:OperatingSegments, aee:AmerenIllinoisElectricDistribution, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value3741323736353533
Percentage of NetIncomeLoss30.842.749.259.730.041.755.653.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax2.63.11.92.72.32.52.02.1
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:AmerenIllinoisElectricDistribution aee:AmerenIllinoisCompany0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, aee:AmerenIllinoisGas, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value5527-11572107
Percentage of NetIncomeLoss45.828.1-1.51.647.525.00.011.3
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax3.82.1-0.10.13.71.50.00.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:AmerenIllinoisGas aee:AmerenIllinoisCompany0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, aee:AmerenIllinoisTransmission, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value2828342427282822
Percentage of NetIncomeLoss23.329.252.338.722.533.344.435.5
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax1.92.12.01.71.72.01.61.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:OperatingSegments aee:AmerenIllinoisTransmission aee:AmerenIllinoisCompany0.00.00.00.00.00.00.00.0

us-gaap:LitigationCase

aee:February2015FERCROEComplaintCase



Period End2020-03-31
Value11
Percentage of NetIncomeLoss9.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax0.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:February2015FERCROEComplaintCase0.0

us-gaap:LitigationCase, dei:LegalEntity

aee:February2015FERCROEComplaintCase, aee:AmerenIllinoisCompany



Period End2020-03-31
Value6
Percentage of NetIncomeLoss5.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax0.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:February2015FERCROEComplaintCase aee:AmerenIllinoisCompany0.0

Profit Loss

us-gaap:ProfitLoss



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value1489536618019369359240153-59290194104333711481073034515111049295150983830496-143-1155374210-40328713974-164155106
Percentage of ProfitLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax10.37.222.113.112.44.920.815.49.7-4.216.812.66.92.420.010.47.52.318.810.87.13.617.710.66.12.918.66.8-9.7-76.518.712.7-24.312.77.83.9-7.29.05.5

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value1219765631218563639678555880301194660339832544675295477323271332898383411057
Percentage of ProfitLoss81.8102.117.835.062.7123.217.526.262.7-132.219.029.976.990.932.131.156.1110.028.421.249.193.925.419.355.125.333.3-22.419.015.7-6.934.127.345.9-67.136.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax8.47.43.94.67.86.03.74.06.15.63.23.85.32.26.43.24.22.55.32.33.53.44.52.03.44.72.32.23.52.01.74.32.11.84.93.3
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany16.714.811.511.515.912.611.210.912.611.69.610.111.45.017.68.58.96.015.06.27.27.313.15.67.014.16.24.711.05.93.913.26.14.214.78.8

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value-9-2030110840-2229516939-362351216102429315112406242-5223127482398541237144221919122224115
Percentage of ProfitLoss-6.1-21.182.260.020.7-31.982.270.425.561.081.062.45.830.365.262.814.036.769.641.138.2-10.275.684.749.078.688.5-28.763.468.6-5.566.665.529.7-136.674.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-0.6-1.518.17.82.6-1.617.110.82.5-2.613.67.90.40.713.06.51.00.813.14.42.7-0.413.48.93.014.66.12.811.88.71.38.45.11.29.96.7
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany-1.3-3.228.413.55.3-3.126.117.74.9-5.221.113.00.81.320.810.72.01.520.57.05.2-0.720.314.15.921.99.65.222.317.13.217.111.12.821.115.1

us-gaap:StatementEquityComponents, dei:LegalEntity

us-gaap:RetainedEarnings, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value121976563121856363
Percentage of ProfitLoss81.8102.117.835.062.7123.217.526.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax8.47.43.94.67.86.03.74.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:RetainedEarnings aee:AmerenIllinoisCompany0.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value-9-2030110840-22295169
Percentage of ProfitLoss-6.1-21.182.260.020.7-31.982.270.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-0.6-1.518.17.82.6-1.617.110.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax us-gaap:RetainedEarnings aee:UnionElectricCompany0.00.00.00.00.00.00.00.0

Increase Decrease In Inventories

us-gaap:IncreaseDecreaseInInventories



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value-2365431-81-435022-68-373446-60-243632-55-94850-75-3769-102-12771-80-135-148
Percentage of IncreaseDecreaseInInventories100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value-41-93524-52-154525-63-163729-49-234025-57-224541-89-3373-88-10565-103-123
Percentage of IncreaseDecreaseInInventories178.3-150.064.877.464.234.990.0113.692.643.2108.863.081.795.8111.178.1103.6244.493.882.0118.789.2105.886.382.791.5128.891.1

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value1816197-29-275-3-5-21-418-11-1-4721321014-5-3-14-221026-14
Percentage of IncreaseDecreaseInInventories-78.3266.735.222.635.862.810.0-13.67.456.8-11.839.118.34.2-11.121.9-3.6-144.44.220.0-18.713.5-4.313.717.314.1-32.510.4

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value-684-637-644-587-567-617-590-532-597-620-526-520-539-590-516-525-510-614-487-436-439-505-442-313-303-373-326-250-317
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-47.5-48.4-38.8-42.6-36.4-43.5-34.2-34.0-37.7-44.2-30.5-33.8-35.6-43.5-27.8-36.8-35.6-46.9-26.6-31.1-28.2-36.9-26.5-19.6-20.5-18.6-19.7-13.1-16.3

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value-323-302-345-291-267-311-338-299-300-316-274-253-227-239-241-169-269-298-240-168-207-201-195-214-138-57-86-19
Percentage of NetCashProvidedByUsedInInvestingActivities47.247.453.649.647.150.457.356.250.351.052.148.742.140.546.732.252.748.549.338.547.239.844.168.445.515.326.47.6
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-22.4-22.9-20.8-21.1-17.2-21.9-19.6-19.1-18.9-22.5-15.9-16.5-15.0-17.6-13.0-11.8-18.8-22.8-13.1-12.0-13.3-14.7-11.7-13.4-9.4-2.8-5.2-1.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany-44.7-46.2-61.2-53.2-35.0-46.1-59.9-51.7-39.5-46.9-47.7-43.9-32.3-40.2-35.7-31.2-39.7-53.9-36.6-32.7-27.8-31.8-34.1-27.6-20.2-8.8-11.9-2.4

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value-328-310-264-257-264-241-192-278-265-230-202-185-68-210-370-184-17015-411-159-169-244-180-204-129-177-218-156
Percentage of NetCashProvidedByUsedInInvestingActivities48.048.741.043.846.639.132.552.344.437.138.435.612.635.671.735.033.3-2.484.436.538.548.340.765.242.647.566.962.4
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax-22.8-23.6-15.9-18.6-17.0-17.0-11.1-17.8-16.7-16.4-11.7-12.0-4.5-15.5-19.9-12.9-11.91.1-22.4-11.3-10.9-17.8-10.8-12.8-8.7-8.8-13.1-8.2
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany-48.2-49.4-24.9-32.2-34.8-33.8-17.0-29.1-33.5-32.9-18.1-19.8-8.6-28.0-31.8-21.2-22.92.0-35.1-18.0-21.1-33.0-16.4-25.0-16.2-16.6-31.5-20.2

Payments To Acquire Property Plant And Equipment

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value636650636581544597577533579609525494504580496504496585486429417475427442275340282227289
Percentage of PaymentsToAcquirePropertyPlantAndEquipment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value3243083442892673113453023003162762572272412412312112982412051742021972151331258669
Percentage of PaymentsToAcquirePropertyPlantAndEquipment50.947.454.149.749.152.159.856.751.851.952.652.045.041.648.645.842.550.949.647.841.742.546.148.648.436.830.530.4

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value278325256255240250210205249240178159196238147175178178155144145199173188137146157129
Percentage of PaymentsToAcquirePropertyPlantAndEquipment43.750.040.343.944.141.936.438.543.039.433.932.238.941.029.634.735.930.431.933.634.841.940.542.549.842.955.756.8

us-gaap:ConsolidationItems

us-gaap:IntersegmentElimination



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value1-316-5-2-3-42-43-7-2-1-6000
Percentage of PaymentsToAcquirePropertyPlantAndEquipment0.2-4.80.9-0.9-0.4-0.5-0.70.4-0.70.5-1.3-0.4-0.2-1.00.00.00.0

us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, aee:AmerenIllinoisElectricDistribution



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value123128139127124114135132122122112122120111123119117
Percentage of PaymentsToAcquirePropertyPlantAndEquipment19.319.721.921.922.819.123.424.821.120.021.324.723.819.124.823.623.6

us-gaap:OperatingSegments, aee:AmerenIllinoisGas



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value617711377517411166606571585151504535
Percentage of PaymentsToAcquirePropertyPlantAndEquipment9.611.817.813.39.412.419.212.410.410.713.511.710.18.810.18.97.1

us-gaap:OperatingSegments, aee:AmerenTransmission



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value170151129127121163124130145181173156134186175164164
Percentage of PaymentsToAcquirePropertyPlantAndEquipment26.723.220.321.922.227.321.524.425.029.733.031.626.632.135.332.533.1

us-gaap:OperatingSegments, aee:OtherSegment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value30-7010-11-27-2-2140112
Percentage of PaymentsToAcquirePropertyPlantAndEquipment0.50.0-1.10.01.8-0.20.2-0.41.2-0.3-0.40.20.80.00.20.20.4

us-gaap:OperatingSegments, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value278325256255240250210205249240178159196238147175178
Percentage of PaymentsToAcquirePropertyPlantAndEquipment43.750.040.343.944.141.936.438.543.039.433.932.238.941.029.634.735.9

us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments, dei:LegalEntity

us-gaap:OperatingSegments, aee:AmerenIllinoisElectricDistribution, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value123128139127124114135132
Percentage of PaymentsToAcquirePropertyPlantAndEquipment19.319.721.921.922.819.123.424.8

us-gaap:OperatingSegments, aee:AmerenIllinoisGas, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value617711377517411166
Percentage of PaymentsToAcquirePropertyPlantAndEquipment9.611.817.813.39.412.419.212.4

us-gaap:OperatingSegments, aee:AmerenIllinoisTransmission, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value14010392859212399104
Percentage of PaymentsToAcquirePropertyPlantAndEquipment22.015.814.514.616.920.617.219.5

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value421156-11299191148-280-23360160-255-1020717-275111-118345-204-37142149-14070-99-2-113-276-325
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax29.211.9-6.87.212.310.4-16.2-1.522.711.4-14.8-0.713.71.3-14.87.8-8.226.4-11.1-2.69.110.9-8.44.4-6.7-0.1-6.8-14.5-16.8

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value10654109725317712314718112921901560-116-311478536-481529922-409-37-110
Percentage of NetCashProvidedByUsedInFinancingActivities25.234.6-97.372.727.7119.6-43.9-639.150.380.6-8.2-900.07.2352.90.414.426.342.6-41.7-97.3-33.8102.0-70.731.440.4-450.032.739.9
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax7.44.16.65.23.412.57.19.411.49.21.25.91.04.4-0.11.1-2.211.24.62.6-3.111.15.91.4-2.70.4-2.2-5.8
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:AmerenIllinoisCompany14.78.319.313.27.026.321.825.423.819.13.715.62.110.1-0.13.0-4.626.613.07.0-6.424.017.32.8-5.81.4-5.1-13.6

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value272108-21449116-57-375-4319233-221-118-25-72-153-11-198-92-114-13112-46-295107-86-112-101-88
Percentage of NetCashProvidedByUsedInFinancingActivities64.669.2191.149.560.7-38.5133.9187.053.320.686.71180.0-12.1-423.555.6-9.9167.8-26.755.9354.18.5-30.9210.7152.986.95600.089.431.9
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax18.98.2-12.93.67.5-4.0-21.8-2.812.12.4-12.8-7.7-1.7-5.3-8.2-0.8-13.8-7.0-6.2-9.40.8-3.4-17.76.7-5.8-5.6-6.1-4.6
Percentage of RevenueFromContractWithCustomerIncludingAssessedTax aee:UnionElectricCompany40.017.2-20.26.115.3-8.0-33.2-4.524.24.7-19.8-12.6-3.2-9.6-13.1-1.3-26.7-12.2-9.7-14.81.5-6.2-26.913.1-10.8-10.5-14.6-11.4

Proceeds From Issuance Of Long Term Debt

us-gaap:ProceedsFromIssuanceOfLongTermDebt



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302016-12-312016-09-302015-12-312015-09-302014-12-312014-09-30
Value465627450045049908530496300240094803000
Percentage of ProceedsFromIssuanceOfLongTermDebt100.0100.0100.00.0100.0100.00.0100.00.0100.0100.0100.00.0100.00.0100.00.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302016-12-312016-09-302015-12-312015-09-302014-12-312014-09-30
Value4653280045000423000000000
Percentage of ProceedsFromIssuanceOfLongTermDebt100.052.30.00.0100.00.00.049.60.00.00.00.00.00.00.00.00.0

Repayments Of Long Term Debt

us-gaap:RepaymentsOfLongTermDebt



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-31
Value85003291993230042500129260011400529163
Percentage of RepaymentsOfLongTermDebt100.00.00.0100.0100.0100.00.00.0100.00.00.0100.0100.00.0100.00.00.0100.0100.0
Percentage of LongTermDebtAndCapitalLeaseObligations0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-30
Value850032919917900425000260011400
Percentage of RepaymentsOfLongTermDebt100.00.00.0100.0100.055.40.00.0100.00.00.00.0100.00.0100.00.00.0
Percentage of LongTermDebtAndCapitalLeaseObligations0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of LongTermDebtAndCapitalLeaseObligations aee:UnionElectricCompany0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Payments For Repurchase Of Common Stock

Repayments Of Long Term Debt

us-gaap:RepaymentsOfLongTermDebt



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-31
Value85003291993230042500129260011400529163
Percentage of RepaymentsOfLongTermDebt100.00.00.0100.0100.0100.00.00.0100.00.00.0100.0100.00.0100.00.00.0100.0100.0
Percentage of LongTermDebtAndCapitalLeaseObligations0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-30
Value850032919917900425000260011400
Percentage of RepaymentsOfLongTermDebt100.00.00.0100.0100.055.40.00.0100.00.00.00.0100.00.0100.00.00.0
Percentage of LongTermDebtAndCapitalLeaseObligations0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of LongTermDebtAndCapitalLeaseObligations aee:UnionElectricCompany0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Debt Instrument Interest Rate Stated Percentage

Effective Income Tax Rate Continuing Operations

us-gaap:EffectiveIncomeTaxRateContinuingOperations



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.120.00.20.180.12-0.0100000000000000090.230.240.220.130.410.38
Percentage of EffectiveIncomeTaxRateContinuingOperations100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.240.00.240.230.25-0.0100000000000000090.260.230.25-0.0200000000000000180.40.39
Percentage of EffectiveIncomeTaxRateContinuingOperations200.00.0120.0127.8208.3100.0113.095.8113.6-15.497.6102.6

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.080.0100000000000000090.140.120.09-0.0099999999999999810.180.240.250.060.380.37
Percentage of EffectiveIncomeTaxRateContinuingOperations66.70.070.066.775.0100.078.3100.0113.646.292.797.4

Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period

us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod

us-gaap:PerformanceShares



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312014-12-312014-09-302014-04-30
Value294320.06656.02857.05915.0288956.02891.07732.07478.0298774.03297.01435.038559.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RestrictedStockUnitsRSU



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value132307.03643.0468.03490.0124925.0545.02377.03206.0181145.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod45.054.716.459.043.218.930.742.960.6

us-gaap:AwardType, us-gaap:Vesting

us-gaap:PerformanceShares, aee:Marketperformancemeasures



Period End2020-03-31
Value252370.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod85.7

us-gaap:PerformanceShares, aee:Renewablegenerationandenergystorageinstallationtargets



Period End2020-03-31
Value41950.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod14.3

Share Based Compensation

us-gaap:ShareBasedCompensation



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-03-31
Value65546554654440566466855998
Percentage of ShareBasedCompensation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Deferred Tax Liabilities

Deferred Tax Assets Net

Unrecognized Tax Benefits

Deferred Tax Assets Valuation Allowance

Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions

Operating Lease Right Of Use Asset

Cash And Cash Equivalents Period Increase Decrease

Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-312015-12-31
Value20317615512211810792968968575352351
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-312015-12-31
Value1401251179993807157524132282899
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents69.071.075.581.178.874.877.259.458.460.356.152.853.828.2

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-312015-12-31
Value24391413128725107655207
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents11.822.29.010.710.27.57.626.011.210.310.59.49.659.0

us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis

us-gaap:FairValueInputsLevel1, us-gaap:EstimateOfFairValueFairValueDisclosure



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value203176155122118107929668
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis, dei:LegalEntity

us-gaap:FairValueInputsLevel1, us-gaap:EstimateOfFairValueFairValueDisclosure, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value1401251179980
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents69.071.075.581.174.8

us-gaap:FairValueInputsLevel1, us-gaap:EstimateOfFairValueFairValueDisclosure, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value243914138
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents11.822.29.010.77.5

us-gaap:FairValueByMeasurementBasis

us-gaap:CarryingReportedAmountFairValueDisclosure



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value203176155122118107929668
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EstimateOfFairValueFairValueDisclosure



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value203176155122118107929668
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FairValueByMeasurementBasis, dei:LegalEntity

us-gaap:CarryingReportedAmountFairValueDisclosure, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value1401251179980
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents69.071.075.581.174.8

us-gaap:CarryingReportedAmountFairValueDisclosure, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value243914138
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents11.822.29.010.77.5

us-gaap:EstimateOfFairValueFairValueDisclosure, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value1401251179980
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents69.071.075.581.174.8

us-gaap:EstimateOfFairValueFairValueDisclosure, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value243914138
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents11.822.29.010.77.5

Proceeds From Repayments Of Short Term Debt

us-gaap:ProceedsFromRepaymentsOfShortTermDebt



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value175-104-4541992027615-45447538-446-22356-50-170197280-482-103-69241-39-403320-25-22-125-220
Percentage of ProceedsFromRepaymentsOfShortTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-30
Value7-2561107354-36108-224162-107109117-106-2017700-1212-32-15784
Percentage of ProceedsFromRepaymentsOfShortTermDebt4.0246.2-24.236.726.7-47.4720.049.334.1-281.6-2.2-413.64.8212.011.889.80.0-0.011.7-17.4-13.3402.6-210.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-31
Value-10490-611500550-28224324360-77-881650-38-1024332-120290
Percentage of ProceedsFromRepaymentsOfShortTermDebt-59.4-86.513.475.40.072.40.062.151.2-109.110.1-0.045.3-44.758.9-0.036.9147.817.8-82.1300.087.3

us-gaap:LossContingenciesByNatureOfContingency

aee:AggregateNuclearPowerIndustryInsurancePolicyLimitForLossesFromTerroristAttacksWithinTwelveMonthPeriod

aee:Nonradiationevent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-30
Value18000001800000180000018000001830000183000
Percentage of AggregateNuclearPowerIndustryInsurancePolicyLimitForLossesFromTerroristAttacksWithinTwelveMonthPeriod100.00.00.00.0100.00.00.00.0100.00.00.00.0100.00.00.00.0100.00.00.00.0100.00.00.0

aee:RadiationEvent



Period End2020-03-312019-12-312019-09-30
Value320000
Percentage of AggregateNuclearPowerIndustryInsurancePolicyLimitForLossesFromTerroristAttacksWithinTwelveMonthPeriod177.80.00.0

us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased

aee:AmountofMegawatts

aee:PurchasedPower



Period End2020-03-312019-12-312019-09-302019-06-302019-03-31
Value102.00.00.00.0102.0
Percentage of AmountofMegawatts100.00.00.00.0100.0

us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased, dei:LegalEntity

aee:April2020ProcurementCapacity, aee:AmerenIllinoisCompany



Period End2020-03-31
Value617.0
Percentage of AmountofMegawatts604.9

aee:PurchasedPower, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-30
Value102.00.00.0
Percentage of AmountofMegawatts100.00.00.0

us-gaap:PublicUtilitiesRegulatoryProceeding, dei:LegalEntity

aee:WindGenerationFacility, aee:UnionElectricCompany



Period End2020-03-312019-09-302019-06-302018-12-312018-09-302018-06-30
Value300.0300.0300.0157.0400.0400.0
Percentage of AmountofMegawatts294.10.00.00.00.00.0

aee:DefinedBenefitPlanNonserviceCostorIncomeComponents



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value23232322221817191611111012
Percentage of DefinedBenefitPlanNonserviceCostorIncomeComponents100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value1311121212981072413
Percentage of DefinedBenefitPlanNonserviceCostorIncomeComponents56.547.852.254.554.550.047.152.643.818.236.410.025.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value5544444455566
Percentage of DefinedBenefitPlanNonserviceCostorIncomeComponents21.721.717.418.218.222.223.521.131.245.545.560.050.0

us-gaap:RetirementPlanType

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value13-94131413-8313149-69119
Percentage of DefinedBenefitPlanNonserviceCostorIncomeComponents56.5-408.756.563.659.1-461.176.573.756.2-627.3100.090.0

us-gaap:PensionPlansDefinedBenefit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value16-114171616-699911-5187
Percentage of DefinedBenefitPlanNonserviceCostorIncomeComponents69.6-495.773.972.772.7-383.352.947.468.8-463.672.770.0

dei:LegalEntity

aee:DefinedBenefitPlanNonserviceCostorIncomeComponentsTracker

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value677874544
Percentage of DefinedBenefitPlanNonserviceCostorIncomeComponentsTracker100.0100.0100.0100.0100.0100.0100.0100.0100.0

aee:Donations



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value1341161846510258125502813152143312112712
Percentage of Donations100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-30
Value40014101400140114101310300310101
Percentage of Donations30.80.00.0100.066.75.60.016.780.00.00.050.080.00.0100.050.080.020.00.050.037.5100.00.060.00.00.075.033.30.083.3100.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-31
Value8010283210020201120121212012232
Percentage of Donations61.50.0100.00.033.344.475.033.320.00.00.0100.00.025.00.050.020.040.00.050.025.0100.066.7100.040.00.0100.050.066.7100.016.7

us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity

aee:FinalRateOrder, us-gaap:Electricity, aee:UnionElectricCompany



Period End2020-03-31
Value8
Percentage of Donations61.5

aee:EffectiveIncomeTaxRateReconciliationNondeductibleExpenseAmortizationofExcessDeferredTaxesPercent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-302017-06-30
Value0.09-0.140.07-0.09-0.07-0.010000000000000002-0.06-0.01-0.020.00.0
Percentage of EffectiveIncomeTaxRateReconciliationNondeductibleExpenseAmortizationofExcessDeferredTaxesPercent100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-302017-06-30
Value0.03-0.080.03-0.04-0.030.0-0.03-0.05-0.030.00.0
Percentage of EffectiveIncomeTaxRateReconciliationNondeductibleExpenseAmortizationofExcessDeferredTaxesPercent33.357.142.944.442.9-0.050.0500.0150.00.00.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-302017-06-30
Value0.15-0.229999999999999980.11-0.12-0.120.0-0.070.00.00.00.0
Percentage of EffectiveIncomeTaxRateReconciliationNondeductibleExpenseAmortizationofExcessDeferredTaxesPercent166.7164.3157.1133.3171.4-0.0116.7-0.0-0.00.00.0

us-gaap:DerivativeInstrumentRisk

aee:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetLiabilityChangeInRealizedUnrealizedGainLossStillHeld

aee:Power



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value-11-19-215-400-30-7-2-2-11-20-214-19-5-6-4-24
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetLiabilityChangeInRealizedUnrealizedGainLossStillHeld100.0100.0100.0100.0100.00.00.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DerivativeInstrumentRisk, dei:LegalEntity

aee:Power, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value-21-23-17-11-400-3
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetLiabilityChangeInRealizedUnrealizedGainLossStillHeld190.9121.181.0-220.0100.00.00.0100.0

aee:Power, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value104-4160000
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetLiabilityChangeInRealizedUnrealizedGainLossStillHeld-90.9-21.119.0320.0-0.00.00.0-0.0

us-gaap:DerivativeInstrumentRisk

aee:FairValueMeasurementWithUnobservableInputsReconciliationRecurringRealizedAndUnrealizedGainsLossesIncludedInRegulatoryAssetsLiabilities

aee:Power



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-31
Value-10-215-4-4-3-1-5-2-10-613-24-6-4-27
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringRealizedAndUnrealizedGainsLossesIncludedInRegulatoryAssetsLiabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DerivativeInstrumentRisk, dei:LegalEntity

aee:Power, aee:AmerenIllinoisCompany



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-30
Value-21-17-11-40-2
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringRealizedAndUnrealizedGainsLossesIncludedInRegulatoryAssetsLiabilities210.081.0-220.0100.0-0.066.7

aee:Power, aee:UnionElectricCompany



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-30
Value11-4160-4-1
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringRealizedAndUnrealizedGainsLossesIncludedInRegulatoryAssetsLiabilities-110.019.0320.0-0.0100.033.3

us-gaap:LitigationCase, us-gaap:RegulatoryAgency

aee:IncentiveaddertoFERCallowedbasereturnoncommonequity

aee:FinalRateOrder, aee:MidwestIndependentTransmissionSystemOperatorInc



Period End2020-03-31
Value0.005
Percentage of IncentiveaddertoFERCallowedbasereturnoncommonequity100.0

aee:NoticeofProposedRulemaking, aee:MidwestIndependentTransmissionSystemOperatorInc



Period End2020-03-31
Value0.01
Percentage of IncentiveaddertoFERCallowedbasereturnoncommonequity200.0

aee:Otherrevenuesnotfromcontractswithcustomers



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value10775945825565
Percentage of Otherrevenuesnotfromcontractswithcustomers100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-03-31
Value24
Percentage of Otherrevenuesnotfromcontractswithcustomers20.044.4

us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, aee:AmerenIllinoisElectricDistribution



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value1211321310121
Percentage of Otherrevenuesnotfromcontractswithcustomers10.028.614.320.033.350.020.037.540.020.033.320.0

us-gaap:OperatingSegments, aee:AmerenIllinoisGas



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value1000000.00.01000000.00.01000000.00.01000000.00.01000000.00.00.01000000.0
Percentage of Otherrevenuesnotfromcontractswithcustomers10.00.014.30.011.10.020.00.04.00.00.020.0

us-gaap:OperatingSegments, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value8554523514443
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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value12113213
Percentage of Otherrevenuesnotfromcontractswithcustomers10.028.614.320.033.350.020.037.5

us-gaap:OperatingSegments, aee:AmerenIllinoisGas, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value1000000.00.01000000.00.01000000.00.01000000.00.0
Percentage of Otherrevenuesnotfromcontractswithcustomers10.00.014.30.011.10.020.00.0

us-gaap:DebtInstrument, us-gaap:ShortTermDebtType

aee:PeakShortTermBorrowingsInterestRate

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Period End2020-03-31
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Percentage of PeakShortTermBorrowingsInterestRate100.0

aee:MissouriCreditAgreement, us-gaap:LineOfCredit



Period End2020-03-31
Value0.0333
Percentage of PeakShortTermBorrowingsInterestRate161.7

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aee:IllinoisCreditAgreement, us-gaap:LineOfCredit, aee:AmerenIllinoisCompany



Period End2020-03-31
Value0.0205
Percentage of PeakShortTermBorrowingsInterestRate99.5

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Period End2020-03-31
Value0.0206
Percentage of PeakShortTermBorrowingsInterestRate100.0

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Period End2020-03-31
Value0.0
Percentage of PeakShortTermBorrowingsInterestRate0.0

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Period End2020-03-31
Value0.0
Percentage of PeakShortTermBorrowingsInterestRate0.0

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Period End2020-03-31
Value0.0206
Percentage of PeakShortTermBorrowingsInterestRate100.0

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Period End2020-03-31
Value0.0333
Percentage of PeakShortTermBorrowingsInterestRate161.7

us-gaap:ShortTermDebtType

us-gaap:CommercialPaper



Period End2020-03-312019-03-312013-03-312012-03-31
Value0.05050.0310.00850.0125
Percentage of PeakShortTermBorrowingsInterestRate245.10.00.00.0

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Period End2020-03-312019-03-31
Value0.0340.029
Percentage of PeakShortTermBorrowingsInterestRate165.00.0

us-gaap:CommercialPaper, aee:AmerenparentDomain



Period End2020-03-312019-03-31
Value0.0330.031
Percentage of PeakShortTermBorrowingsInterestRate160.20.0

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Period End2020-03-312019-03-31
Value0.05050.0297
Percentage of PeakShortTermBorrowingsInterestRate245.10.0

aee:Revenuesfromalternativerevenueprograms



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value6623-13082932-11102036-10512
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dei:LegalEntity

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Period End2020-03-312019-03-31
Value6714
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us-gaap:OperatingSegments, aee:AmerenIllinoisElectricDistribution



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value4637-145122249-98153142-9616
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us-gaap:OperatingSegments, aee:AmerenIllinoisGas



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value11-214-3-13-2-5-3-6-11
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us-gaap:OperatingSegments, aee:AmerenTransmission



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value12-6-12-8-5-4-12-5-48-22
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us-gaap:OperatingSegments, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value-3-62601501-5-4-8-6-7
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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value4637-145122249-9815
Percentage of Revenuesfromalternativerevenueprograms69.7160.9111.5150.075.9153.188.30.0

us-gaap:OperatingSegments, aee:AmerenIllinoisGas, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value11-214-3-13-2-5
Percentage of Revenuesfromalternativerevenueprograms16.7-8.7-0.850.0-10.3-40.61.80.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value10-7-12-9-5-6-10-5
Percentage of Revenuesfromalternativerevenueprograms15.2-30.49.2-112.5-17.2-18.89.00.0

us-gaap:AwardType

aee:SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsGrantedinPeriodFairValue

us-gaap:PerformanceShares



Period End2020-03-31
Value24
Percentage of SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsGrantedinPeriodFairValue100.0

us-gaap:RestrictedStockUnitsRSU



Period End2020-03-31
Value10
Percentage of SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsGrantedinPeriodFairValue41.7

us-gaap:StatementEquityComponents

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue

us-gaap:AdditionalPaidInCapital



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-12776-211167-11
Percentage of AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AllowanceForDoubtfulAccountsReceivableWriteOffs



Period End2020-03-312019-03-31
Value12
Percentage of AllowanceForDoubtfulAccountsReceivableWriteOffs100.0100.0

dei:LegalEntity

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Period End2020-03-312019-03-31
Value0.01000000.0
Percentage of AllowanceForDoubtfulAccountsReceivableWriteOffs0.050.0

us-gaap:AmortizationOfFinancingCostsAndDiscounts



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value55545456565565656656565566559
Percentage of AmortizationOfFinancingCostsAndDiscounts100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value2333333433343343434343433322
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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value2120221121212121212122122222
Percentage of AmortizationOfFinancingCostsAndDiscounts40.020.040.00.040.050.020.016.740.016.740.020.033.320.033.320.033.316.740.016.740.033.320.040.033.333.340.040.0

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount



Period End2020-03-312019-09-302019-03-312018-09-302014-09-302013-09-302012-09-30
Value0.00.00.00.00.00.01000000.0
Percentage of AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount0.00.00.00.00.00.0100.0

us-gaap:AssetRetirementObligationAccretionExpense



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302015-12-312015-09-302015-06-302015-03-31
Value777867677676665
Percentage of AssetRetirementObligationAccretionExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302015-12-312015-09-302015-06-302015-03-31
Value0.00.00.00.00.0-1000000.00.00.01000000.00.00.00.00.00.01000000.0
Percentage of AssetRetirementObligationAccretionExpense0.00.00.00.00.0-14.30.00.014.30.00.00.00.00.020.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302015-12-312015-09-302015-06-302015-03-31
Value777867677676665
Percentage of AssetRetirementObligationAccretionExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AssetRetirementObligationLiabilitiesSettled



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302015-12-31
Value14103433211843
Percentage of AssetRetirementObligationLiabilitiesSettled100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302015-12-31
Value0.00.00.00.00.0-1000000.00.00.01000000.00.00.00.0
Percentage of AssetRetirementObligationLiabilitiesSettled0.00.00.00.00.0-33.30.00.0100.00.00.00.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302015-12-31
Value14103433211832
Percentage of AssetRetirementObligationLiabilitiesSettled100.0100.0100.0100.0100.0100.0100.0100.0100.0100.075.066.7

us-gaap:CapitalExpendituresIncurredButNotYetPaid



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-06-302017-03-31
Value235601055208327233202159175164
Percentage of CapitalExpendituresIncurredButNotYetPaid100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value12735-15371065-141471147521574
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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-06-302017-03-31
Value9723799227148073896150
Percentage of CapitalExpendituresIncurredButNotYetPaid41.33.3370.016.444.284.4200.034.336.156.034.930.5

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Period End2020-03-312019-03-312018-03-312017-03-31
Value70113
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Period End2020-03-312019-03-31
Value70
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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value27213341115-4721114
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value1581861391451194
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect55.638.154.5150.0118.260.0-350.071.452.481.8100.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value-15251141-1815311
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect-55.6119.03.025.036.46.7450.0214.314.39.125.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
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Value202019191919201919191918
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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value736969696970686969666565
Percentage of DefinedBenefitPlanExpectedReturnOnPlanAssets365.0345.0363.2363.2363.2368.4340.0363.2363.2347.4342.1361.1

us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanInterestCost

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value10111110111010911121211
Percentage of DefinedBenefitPlanInterestCost100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PensionPlansDefinedBenefit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value434846464743424242454445
Percentage of DefinedBenefitPlanInterestCost430.0436.4418.2460.0427.3430.0420.0466.7381.8375.0366.7409.1

us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value-9-9-9-9-9-6-7-9-4-4-5-4
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PensionPlansDefinedBenefit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value11656614161614161616
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost-122.2-66.7-55.6-66.7-66.7-233.3-228.6-177.8-350.0-400.0-320.0-400.0

us-gaap:RetirementPlanType, dei:LegalEntity

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value-8-7-8-8-7-6-6-9
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost88.977.888.988.977.8100.085.7100.0

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value-1-2-1-1-20-10
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost11.122.211.111.122.2-0.014.3-0.0

us-gaap:PensionPlansDefinedBenefit, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value7555591110
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost-77.8-55.6-55.6-55.6-55.6-150.0-157.1-111.1

us-gaap:PensionPlansDefinedBenefit, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value42111566
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost-44.4-22.2-11.1-11.1-11.1-83.3-85.7-66.7

us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanServiceCost

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value454545655565
Percentage of DefinedBenefitPlanServiceCost100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PensionPlansDefinedBenefit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value272222222225252525232423
Percentage of DefinedBenefitPlanServiceCost675.0440.0550.0440.0550.0500.0416.7500.0500.0460.0400.0460.0

us-gaap:DepreciationAmortizationAndAccretionNet



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value263257251249245239236233230223220216217210206209210195195192195184177176166179188196190
Percentage of DepreciationAmortizationAndAccretionNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value1061021021011009794949087868583828079777474727269656260545250
Percentage of DepreciationAmortizationAndAccretionNet40.339.740.640.640.840.639.840.339.139.039.139.438.239.038.837.836.737.937.937.536.937.536.735.236.130.227.725.5

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value14814514213913813513313313213012912812712512412713012011811712111310911210410210093
Percentage of DepreciationAmortizationAndAccretionNet56.356.456.655.856.356.556.457.157.458.358.659.358.559.560.260.861.961.560.560.962.161.461.663.662.757.053.247.4

us-gaap:TradingActivityByType

us-gaap:DerivativeNonmonetaryNotionalAmountEnergyMeasure

srt:NaturalGasReserves



Period End2020-03-312019-03-31
Value167156
Percentage of DerivativeNonmonetaryNotionalAmountEnergyMeasure100.0100.0

us-gaap:TradingActivityByType, dei:LegalEntity

srt:NaturalGasReserves, aee:AmerenIllinoisCompany



Period End2020-03-312019-03-31
Value147136
Percentage of DerivativeNonmonetaryNotionalAmountEnergyMeasure88.087.2

us-gaap:TradingActivityByType

us-gaap:DerivativeNonmonetaryNotionalAmountMass

aee:Uranium



Period End2020-03-312019-03-31
Value365000.0565000.0
Percentage of DerivativeNonmonetaryNotionalAmountMass100.0100.0

us-gaap:TradingActivityByType, dei:LegalEntity

aee:Uranium, aee:UnionElectricCompany



Period End2020-03-312019-03-31
Value365000.0565000.0
Percentage of DerivativeNonmonetaryNotionalAmountMass100.0100.0

us-gaap:TradingActivityByType

us-gaap:DerivativeNonmonetaryNotionalAmountVolume

aee:FuelOils



Period End2020-03-312019-03-31
Value6258
Percentage of DerivativeNonmonetaryNotionalAmountVolume100.0100.0

us-gaap:TradingActivityByType, dei:LegalEntity

aee:FuelOils, aee:UnionElectricCompany



Period End2020-03-312019-03-31
Value6258
Percentage of DerivativeNonmonetaryNotionalAmountVolume100.0100.0

us-gaap:StatementEquityComponents

us-gaap:DividendsCommonStockCash

us-gaap:RetainedEarnings



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value122122117117116117111112111
Percentage of DividendsCommonStockCash100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementEquityComponents, dei:LegalEntity

us-gaap:DividendsPreferredStockCash

us-gaap:RetainedEarnings, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value1000000.01000000.00.01000000.01000000.01000000.00.01000000.0
Percentage of DividendsPreferredStockCash100.0100.00.0100.0100.0100.00.0100.0

us-gaap:RetainedEarnings, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value1000000.00.01000000.01000000.01000000.00.01000000.01000000.0
Percentage of DividendsPreferredStockCash100.00.00.0100.0100.00.00.0100.0

us-gaap:EarningsPerShareBasicAndDiluted



Period End2020-03-312019-03-312018-03-312017-06-302017-03-312016-06-302016-03-312013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.590.780.620.790.420.610.430.39-0.6-4.761.540.87-1.660.11.180.570.290.21-0.70.640.43
Percentage of EarningsPerShareBasicAndDiluted100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.210.00.210.210.210.00.210.210.210.00.350.35
Percentage of EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.210.00.210.210.210.00.210.210.210.00.350.35
Percentage of EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.210.00.210.210.210.00.210.210.210.00.350.35
Percentage of EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0

us-gaap:EffectiveIncomeTaxRateReconciliationNondeductibleExpenseDepreciation



Period End2020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.010.00.00.00.00.00.00.00.00.010.0
Percentage of EffectiveIncomeTaxRateReconciliationNondeductibleExpenseDepreciation100.00.00.00.00.00.00.00.00.0100.00.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.010.0-0.010.0-0.01-0.01-0.010.0-0.01-0.02-0.01
Percentage of EffectiveIncomeTaxRateReconciliationNondeductibleExpenseDepreciation100.00.00.00.00.00.00.00.00.0-200.00.0

aee:UnionElectricCompany



Period End2020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.00.00.00.00.00.00.00.010.00.010.0
Percentage of EffectiveIncomeTaxRateReconciliationNondeductibleExpenseDepreciation0.00.00.00.00.00.00.00.00.0100.00.0

us-gaap:EffectiveIncomeTaxRateReconciliationOtherAdjustments



Period End2020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.00.01-0.010.00.00.00.00.0-0.01-0.01-0.01
Percentage of EffectiveIncomeTaxRateReconciliationOtherAdjustments0.0100.0100.00.00.00.00.00.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.00.00.00.00.00.00.0-0.010.00.0
Percentage of EffectiveIncomeTaxRateReconciliationOtherAdjustments0.00.0-0.00.00.00.00.0100.0-0.0-0.0

aee:UnionElectricCompany



Period End2020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.00.010.019999999999999997-0.030.00.00.00.00.00.00.0
Percentage of EffectiveIncomeTaxRateReconciliationOtherAdjustments0.0100.0-200.00.00.00.00.00.0-0.0-0.0-0.0

us-gaap:EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value80014006
Percentage of EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount100.00.00.0100.00.00.0100.0

us-gaap:EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitPercent



Period End2020-03-312019-12-312019-09-302019-03-312018-09-30
Value0.050.0-0.010.070.0
Percentage of EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitPercent100.00.0100.0100.00.0

us-gaap:EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.060.00.060.060.060.00.060.050.070.00.070.04
Percentage of EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.070.00.060.070.070.00.050.080.070.0099999999999999950.070.05
Percentage of EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes116.70.0100.0116.7116.70.083.3160.0100.00.0100.0125.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.030.00.050.040.040.00.040.040.040.0100000000000000020.030.03
Percentage of EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes50.00.083.366.766.70.066.780.057.10.042.975.0

us-gaap:EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.00.00.010.00.010.00.010.00.010.00.010.0
Percentage of EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment0.00.0100.00.0100.00.0100.00.0100.00.0100.00.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0.010.00.010.010.010.010.00.010.010.00.010.01
Percentage of EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment0.00.0100.00.0100.00.00.00.0100.00.0100.00.0

us-gaap:ExciseAndSalesTaxes



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value65557663706078745648615150466151504461515749565060594955554845574451544446
Percentage of ExciseAndSalesTaxes100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-30
Value35262725392926282217101119179112015910231891126101122910181010
Percentage of ExciseAndSalesTaxes53.847.335.539.755.748.333.337.839.335.416.421.638.037.014.821.640.034.114.819.640.436.716.122.043.316.922.440.016.420.840.017.522.7

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-31
Value30294938313152463431514031295240302952413431473934493833463827
Percentage of ExciseAndSalesTaxes46.252.764.560.344.351.766.762.260.764.683.678.462.063.085.278.460.065.985.280.459.663.383.978.056.783.177.660.083.679.260.0

us-gaap:DerivativeInstrumentRisk

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements

aee:Power



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value31-3-3-3-2-2-1-2-301222033430
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.00.0100.0100.0100.0100.00.0

us-gaap:DerivativeInstrumentRisk, dei:LegalEntity

aee:Power, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value-4-4-4-4-3-3-3-3
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements-133.3-400.0133.3133.3100.0150.0150.0300.0

aee:Power, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value75110112
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements233.3500.0-33.3-33.3-0.0-50.0-50.0-200.0

us-gaap:GainLossOnInvestments



Period End2020-03-312019-03-31
Value-11164
Percentage of GainLossOnInvestments100.0100.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-03-31
Value-11164
Percentage of GainLossOnInvestments100.0100.0

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value1691194582192208546431419514149530816159604240138615531581766749025016349417291532264-533450224119-27238181
Percentage of IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value16012885831601108681128117939513244196759846157528979129508912854521175546163645414579
Percentage of IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments94.7107.618.637.972.7129.418.525.865.683.018.830.882.074.632.531.271.075.428.432.950.6117.926.320.054.625.931.457.122.020.8-8.636.228.645.4-537.033.2

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value-10-2235212344-30360223520378193911390151241538010168-1035220377388134603852273429314433344173
Percentage of IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments-5.9-18.576.956.220.0-35.377.671.026.70.076.462.75.618.664.662.917.424.668.763.938.6-14.971.881.247.278.577.965.972.486.0-6.465.164.327.7-1274.172.7

us-gaap:IncreaseDecreaseInAccountsPayableAndAccruedLiabilities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value-221202-614-2131761140-249215048-231215446-246170835-215197-7-183-127-11-220-221-181
Percentage of IncreaseDecreaseInAccountsPayableAndAccruedLiabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value-2029-10-4-3431-917-5243-734-5129313-3326-931-116-1149-17-16-47
Percentage of IncreaseDecreaseInAccountsPayableAndAccruedLiabilities9.014.4166.7-28.616.017.6-81.842.520.920.00.070.822.113.575.028.313.415.3-112.588.65.13.014.3-7.7-7.1154.57.321.3

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value-17216959-167147-832-1921781817-186158-2-2-1721803-9-17117612-153-139-4-136-144
Percentage of IncreaseDecreaseInAccountsPayableAndAccruedLiabilities77.883.7-83.364.378.483.5-72.780.077.182.80.035.480.573.5-50.0-4.369.9105.937.5-25.779.589.3-171.483.6109.436.461.865.2

us-gaap:IncreaseDecreaseInAccruedTaxesPayable



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value47-126414928-102-135649-83554736-106395030-138334833-144321841223571
Percentage of IncreaseDecreaseInAccruedTaxesPayable100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value16736-341227-17-2414046-66-2-419-11-38-4-3024-20-13-2046
Percentage of IncreaseDecreaseInAccruedTaxesPayable34.0-5.687.8-69.442.9-26.5130.8-42.92.0-48.283.6-140.4-5.63.848.7-22.0-10.0-5.8-12.1-62.572.71.40.0-5.67.3-9.10.064.8

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value55-163396544-149-411636-161711835-154854931-2421208340-1754330383039-1
Percentage of IncreaseDecreaseInAccruedTaxesPayable117.0129.495.1132.7157.1146.130.8207.173.5194.012.7251.197.2145.3217.998.0103.3175.4363.6172.9121.2121.5134.4166.792.7136.4111.4-1.4

us-gaap:IncreaseDecreaseInOtherOperatingAssets



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value3345-314-410-7-1-68-15-73315-20-4-335-11-14-1535590-5240-14-3932
Percentage of IncreaseDecreaseInOtherOperatingAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value48162-314-2-2612-1-2140-4-7-101-2-6-1174161-16-1-2-12
Percentage of IncreaseDecreaseInOtherOperatingAssets133.3266.735.6-66.7-21.4-25.040.028.6200.0-100.0150.06.728.642.40.020.0175.030.320.018.242.976.574.567.830.8-2.514.330.8

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value-2-928-716-2-2-35-110-8-111722-9-5-2010-13-3-62528-3841-13-29
Percentage of IncreaseDecreaseInOtherOperatingAssets-66.7-300.062.2233.3114.350.0-20.042.9-500.0183.30.053.3157.151.5146.745.0125.060.6200.0118.221.440.59.131.173.1102.592.974.4

us-gaap:IncreaseDecreaseInOtherOperatingLiabilities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value-18-44-5274-11-7257-57-19-918319-1713-25-15-146-3342-7349296564809
Percentage of IncreaseDecreaseInOtherOperatingLiabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value-14-18-1136-12-5218-22-3658-5-5-117-1312-1416-33432-347124392642
Percentage of IncreaseDecreaseInOtherOperatingLiabilities77.840.921.248.6109.172.2360.0-314.363.2-26.3-88.9-27.8-166.7-57.9-41.2-100.0-48.093.3-114.3-550.0-12.176.246.6144.982.860.040.652.5

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value0-28-3232-4-20-421-10-27-20204-14-24343-7-2440-5-6-337531414
Percentage of IncreaseDecreaseInOtherOperatingLiabilities-0.063.661.543.236.427.8-80.0300.017.5142.1222.2111.1133.3-73.7141.2261.5-12.046.7171.4666.715.2-14.345.214.317.24.621.917.5

us-gaap:IncreaseDecreaseInPensionAndPostretirementObligations



Period End2020-03-312019-03-31
Value0-4
Percentage of IncreaseDecreaseInPensionAndPostretirementObligations0.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-03-31
Value-2-3
Percentage of IncreaseDecreaseInPensionAndPostretirementObligations0.075.0

aee:UnionElectricCompany



Period End2020-03-312019-03-31
Value2-1
Percentage of IncreaseDecreaseInPensionAndPostretirementObligations0.025.0

us-gaap:IncreaseDecreaseInReceivables



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value5-69-5650-4-105-4114426-6598-44-6323166-55-154-93248-15-78869510-109-17-40
Percentage of IncreaseDecreaseInReceivables100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value6717-9156212-57346611-54-163631-17222912-984193-4494584-35-42
Percentage of IncreaseDecreaseInReceivables120.0-10.1-30.4-182.0-1400.0-20.0-4.9-39.6130.8-1100.0220.0-55.136.4-57.1134.8-10.2-40.0-18.8-133.3-306.285.4-620.056.4109.361.140.032.1247.1

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value3-107-51139-56-124-49209-4-71-7152-28-100-8184-81-123-29140-60-66-21-250-3-61-16
Percentage of IncreaseDecreaseInReceivables60.0155.191.1278.01400.0118.1119.5145.1-15.41183.3-140.0155.163.6158.7-34.8110.8147.379.9322.2437.5-125.0440.026.9-2.352.6-30.056.094.1

us-gaap:IncreaseDecreaseInRegulatoryAssetsAndLiabilities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value14-17-14322-2612-130-63-2053-9311-7-69-38-27-81-20-9-3-62651185840
Percentage of IncreaseDecreaseInRegulatoryAssetsAndLiabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value28-8-14617-1862-8341629-993519-45-27-16-32-53034-3380893511
Percentage of IncreaseDecreaseInRegulatoryAssetsAndLiabilities200.047.1102.177.369.2516.763.8-6.3-80.054.7106.5318.2-271.465.271.159.339.525.0-333.3-1133.353.2123.175.460.327.5

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value-16-1224-11-52-43-68-38229-28-29-24-5-10-45-16-38-36-27-10292128
Percentage of IncreaseDecreaseInRegulatoryAssetsAndLiabilities-114.370.6-1.418.242.3-433.333.1107.9190.041.5-9.7-254.5414.334.813.237.055.680.0422.21200.043.5-15.424.636.270.0

us-gaap:IncrementalCommonSharesAttributableToEquityForwardAgreements



Period End2020-03-312019-12-312019-09-302019-03-312018-12-312018-09-30
Value600000.00.0200000.00.00.00.0
Percentage of IncrementalCommonSharesAttributableToEquityForwardAgreements100.00.0100.00.00.00.0

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-312016-09-302015-12-312015-09-302014-12-312014-09-302013-09-302012-09-30
Value10111022102000010120
Percentage of IncrementalCommonSharesAttributableToShareBasedPaymentArrangements100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RelatedPartyTransaction, dei:LegalEntity

us-gaap:InterestExpenseRelatedParty

aee:MoneyPool, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value1000000.00.01000000.01000000.00.00.01000000.01000000.0
Percentage of InterestExpenseRelatedParty100.00.0100.0100.00.00.0100.0100.0

aee:MoneyPool, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value1000000.00.01000000.01000000.00.00.01000000.01000000.0
Percentage of InterestExpenseRelatedParty100.00.0100.0100.00.00.0100.0100.0

us-gaap:InterestIncomeSecuritiesTaxExempt



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value6666676766767776777677677777777777777
Percentage of InterestIncomeSecuritiesTaxExempt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-31
Value6666676766767776777677677777777
Percentage of InterestIncomeSecuritiesTaxExempt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased, dei:LegalEntity

us-gaap:LongTermPurchaseCommitmentAmount

aee:April2020Procurement, aee:AmerenIllinoisCompany



Period End2020-03-31
Value92
Percentage of LongTermPurchaseCommitmentAmount100.0

aee:April2020ProcurementCapacity, aee:AmerenIllinoisCompany



Period End2020-03-31
Value4
Percentage of LongTermPurchaseCommitmentAmount4.3

us-gaap:StatementEquityComponents

us-gaap:MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders

us-gaap:NoncontrollingInterest



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value212121212
Percentage of MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-09-302013-06-302012-09-302012-06-302011-09-30
Value-1-400-15-22-1-30-20211-42-20-40150-35-10-43-11
Percentage of OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax100.0100.00.00.0100.0100.0100.0100.0100.0100.00.0100.00.0100.0100.0100.0100.0100.00.0100.00.0100.00.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementEquityComponents

aee:DeferredRetirementBenefitCosts



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-16001-3-2-21
Percentage of OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax100.0-150.00.00.0-100.0-60.0100.0-100.0-100.0

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-09-302013-06-302012-09-302012-06-302011-09-302011-06-30
Value01000-10002010-11031-1040-1003-583010-1
Percentage of OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax0.0100.00.00.00.0100.00.00.00.0100.00.0100.00.0100.00.0100.0100.0100.00.0100.00.0100.00.0100.0100.0100.0100.0100.00.0100.0

us-gaap:OtherIncome



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-03-312010-09-302010-06-302010-03-31
Value20212322100104111000322321001012131
Percentage of OtherIncome100.00.0100.0100.0100.0100.0100.0100.0100.00.00.0100.00.0100.0100.0100.0100.00.00.00.0100.0100.0100.0100.0100.0100.00.00.0100.00.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302012-09-302012-06-302011-09-30
Value1011101200013110-1002313110110
Percentage of OtherIncome50.00.050.0100.050.00.050.0100.00.00.00.0100.075.0100.0100.00.00.00.00.066.7150.050.0100.050.0100.00.0100.00.00.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value112211201201000012000
Percentage of OtherIncome50.00.0100.0200.050.033.3100.00.0100.00.00.0100.00.00.00.00.0100.00.00.00.00.0

us-gaap:OtherInterestAndDividendIncome



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302012-09-302012-06-302011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value12232122230322344244423222105111211
Percentage of OtherInterestAndDividendIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302012-09-302012-06-302011-09-30
Value111222112212232342334221211000
Percentage of OtherInterestAndDividendIncome100.050.050.066.7100.0200.050.050.0100.066.70.066.7100.0150.066.775.0100.0100.075.075.0100.0100.066.750.0100.050.0100.00.00.00.0

us-gaap:OtherNoncashIncomeExpense



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-31
Value-1736-38-23-10-9-23214-132432-521115113-145
Percentage of OtherNoncashIncomeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value21-8-11-6-812-1100-7233722313221321
Percentage of OtherNoncashIncomeExpense-11.833.3-133.333.312.526.180.0-11.1-100.0-33.350.00.00.053.8100.075.0100.0350.0-40.0100.027.386.7200.0200.033.3-21.440.00.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312014-12-31
Value-2-3-5-3-2-3-4-6-40-1-2-1-5000-1-2
Percentage of OtherNoncashIncomeExpense11.8-100.0-83.3100.0-25.013.040.066.7200.00.0-50.0-200.0-25.038.50.00.00.0-50.0-13.3

us-gaap:OtherNoninterestExpense



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value245334242423437423543143434444344331
Percentage of OtherNoninterestExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-30
Value212221210201212211312021131012111
Percentage of OtherNoninterestExpense100.025.040.066.766.725.0100.025.00.050.00.033.350.033.328.650.050.033.360.025.066.70.050.033.325.0100.025.00.025.050.033.325.025.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-31
Value2321112122202221113111212223211
Percentage of OtherNoninterestExpense100.075.040.033.333.325.0100.025.0100.050.0100.00.050.066.728.625.050.033.360.025.033.3100.050.033.350.066.750.075.050.025.033.3

us-gaap:PaymentOfFinancingAndStockIssuanceCosts



Period End2020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302016-12-312016-09-302015-12-312015-09-302014-12-312014-09-30
Value36045090618010070
Percentage of PaymentOfFinancingAndStockIssuanceCosts100.0100.00.0100.0100.00.0100.00.0100.0100.0100.00.0100.00.0100.00.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302016-12-312016-09-302015-12-312015-09-302014-12-312014-09-30
Value3204104000201010
Percentage of PaymentOfFinancingAndStockIssuanceCosts100.033.30.0100.020.00.044.40.00.00.025.00.010.00.014.30.0

us-gaap:PaymentsForNuclearFuel



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value35514212214412112232714173212221117462101143822
Percentage of PaymentsForNuclearFuel100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value35514212214412112232714173212221117462101143822
Percentage of PaymentsForNuclearFuel100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsForProceedsFromOtherInvestingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302013-03-312012-09-302012-03-312011-03-312010-03-31
Value-2-604-1-5-7-82-4-502-6-102-13-4-30-8-126111
Percentage of PaymentsForProceedsFromOtherInvestingActivities100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302017-12-312017-09-302016-12-312016-09-302015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312012-09-302011-09-302011-03-31
Value-1-61200-70-2-200-1-40-1-2-1-1-2-1
Percentage of PaymentsForProceedsFromOtherInvestingActivities50.0100.00.050.0-0.0-0.0100.0-0.040.033.3-0.0-0.025.0133.30.012.5200.00.0-16.70.0-100.0

us-gaap:PaymentsOfDividendsCommonStock



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-312010-03-31
Value12212211711711611711111211111110610710710710310310310499100999997979797909391
Percentage of PaymentsOfDividendsCommonStock100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsOfDividendsMinorityInterest



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value2121212121212121212121212212212212232
Percentage of PaymentsOfDividendsMinorityInterest100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

us-gaap:PaymentsOfDividendsPreferredStockAndPreferenceStock

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value1000000.01000000.00.01000000.01000000.01000000.00.01000000.01000000.01000000.00.01000000.01000000.01000000.00.01000000.01000000.01000000.00.01000000.01000000.01000000.00.01000000.01000000.00.01000000.01000000.0
Percentage of PaymentsOfDividendsPreferredStockAndPreferenceStock100.0100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.00.0100.0100.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-03-312013-03-312012-09-302012-03-312011-03-31
Value1000000.00.01000000.01000000.01000000.00.01000000.01000000.01000000.00.01000000.01000000.01000000.00.01000000.01000000.01000000.00.01000000.01000000.01000000.00.01000000.01000000.01000000.01000000.01000000.01000000.0
Percentage of PaymentsOfDividendsPreferredStockAndPreferenceStock100.00.00.0100.0100.00.00.0100.0100.00.00.0100.0100.00.00.0100.0100.00.00.0100.0100.00.00.0100.0100.00.0100.0100.0

us-gaap:PaymentsRelatedToTaxWithholdingForShareBasedCompensation



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value20000290001924001551003200012
Percentage of PaymentsRelatedToTaxWithholdingForShareBasedCompensation100.00.00.00.0100.00.00.00.0100.0100.00.00.0100.0100.00.00.0100.00.00.00.0100.0

us-gaap:PaymentsToInvestInDecommissioningFund



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-30
Value9696573943913826
Percentage of PaymentsToInvestInDecommissioningFund100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-30
Value9696573943913826
Percentage of PaymentsToInvestInDecommissioningFund100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

us-gaap:PreferredStockDividendsIncomeStatementImpact

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-06-302013-03-312012-09-302012-06-302012-03-312011-06-302011-03-312010-09-302010-06-30
Value1101110111011101110111011110111112
Percentage of PreferredStockDividendsIncomeStatementImpact100.0100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value101110111011101110111011111111111112
Percentage of PreferredStockDividendsIncomeStatementImpact100.00.00.0100.0100.00.00.0100.0100.00.00.0100.0100.00.00.0100.0100.00.00.0100.0100.00.00.0100.0100.00.0100.0100.00.0100.0100.00.0100.0100.0100.0100.0

dei:LegalEntity

us-gaap:ProceedsFromContributionsFromParent

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312011-03-31
Value1001500080060206
Percentage of ProceedsFromContributionsFromParent100.0100.00.00.00.0100.00.0100.0100.0100.0

us-gaap:StatementEquityComponents, dei:LegalEntity

us-gaap:AdditionalPaidInCapital, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value-10015000240060
Percentage of ProceedsFromContributionsFromParent-100.0100.00.00.00.0300.00.0100.0

us-gaap:ProceedsFromDecommissioningFund



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-30
Value8189593637883423
Percentage of ProceedsFromDecommissioningFund100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-30
Value8189593637883423
Percentage of ProceedsFromDecommissioningFund100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromIssuanceOfCommonStock



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312011-09-302011-06-302011-03-312010-03-31
Value131417181918162317000017151720
Percentage of ProceedsFromIssuanceOfCommonStock100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.00.00.0100.0100.0100.0100.0

dei:LegalEntity

us-gaap:ProvisionForDoubtfulAccounts

aee:AmerenIllinoisCompany



Period End2020-03-312019-03-31
Value12
Percentage of ProvisionForDoubtfulAccounts100.0100.0

aee:UnionElectricCompany



Period End2020-03-312019-03-31
Value21
Percentage of ProvisionForDoubtfulAccounts200.050.0

us-gaap:PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value4878611119586467758118658109710889891096141313
Percentage of PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-30
Value231323321200101215111011
Percentage of PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity50.037.514.337.533.327.327.322.220.025.00.00.016.70.014.340.012.545.512.516.720.00.010.011.1

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-03-31
Value25654887466457637675489878778786
Percentage of PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity50.062.585.762.566.772.772.777.880.075.0100.0100.083.3100.085.760.087.554.587.583.380.0100.090.088.9100.080.087.587.588.987.588.9100.0

us-gaap:LitigationCase, us-gaap:Range, us-gaap:RegulatoryAgency

us-gaap:PublicUtilitiesApprovedReturnOnEquityPercentage

aee:FinalRateOrder, srt:Maximum, aee:MidwestIndependentTransmissionSystemOperatorInc



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-09-30
Value0.10820.00.00.00.10820.0
Percentage of PublicUtilitiesApprovedReturnOnEquityPercentage100.00.00.00.0100.00.0

us-gaap:LitigationCase, us-gaap:RegulatoryAgency

aee:FinalRateOrder, aee:MidwestIndependentTransmissionSystemOperatorInc



Period End2020-03-312019-11-302019-12-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-31
Value0.10320.09880.09880.00.00.10320.00.00.10320.00.00.1032
Percentage of PublicUtilitiesApprovedReturnOnEquityPercentage95.40.00.00.00.095.40.00.00.00.00.00.0

us-gaap:RegulatoryAgency

aee:MidwestIndependentTransmissionSystemOperatorInc



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value0.12380.00.00.00.12380.00.00.00.12380.00.00.00.1238
Percentage of PublicUtilitiesApprovedReturnOnEquityPercentage114.40.00.00.0114.40.00.00.00.00.00.00.00.0

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Period End2020-03-31
Value0.541
Percentage of PublicUtilitiesRequestedEquityCapitalStructurePercentage100.0

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us-gaap:PublicUtilitiesRequestedRateIncreaseDecreaseAmount

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Period End2020-03-31
Value32
Percentage of PublicUtilitiesRequestedRateIncreaseDecreaseAmount100.0

aee:PendingRateCase, srt:NaturalGasReserves, aee:AmerenIllinoisCompany



Period End2020-02-29
Value102
Percentage of PublicUtilitiesRequestedRateIncreaseDecreaseAmount0.0

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Period End2020-06-30
Value45
Percentage of PublicUtilitiesRequestedRateIncreaseDecreaseAmount0.0

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Period End2020-03-31
Value102
Percentage of PublicUtilitiesRequestedRateIncreaseDecreaseAmount318.8

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Period End2020-03-312019-09-30
Value321
Percentage of PublicUtilitiesRequestedRateIncreaseDecreaseAmount100.00.0

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us-gaap:PublicUtilitiesRequestedReturnOnEquityPercentage

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Period End2020-03-31
Value0.105
Percentage of PublicUtilitiesRequestedReturnOnEquityPercentage100.0

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Period End2020-03-31
Value0.105
Percentage of PublicUtilitiesRequestedReturnOnEquityPercentage100.0

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Period End2020-03-31
Value0.098
Percentage of PublicUtilitiesRequestedReturnOnEquityPercentage93.3

srt:Minimum, aee:FinalRateOrder, us-gaap:Electricity, aee:UnionElectricCompany



Period End2020-03-31
Value0.094
Percentage of PublicUtilitiesRequestedReturnOnEquityPercentage89.5

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Period End2020-03-31
Value0.098
Percentage of PublicUtilitiesRequestedReturnOnEquityPercentage93.3

srt:Minimum, aee:PendingRateCase, us-gaap:Electricity, us-gaap:SubsequentEvent, aee:UnionElectricCompany



Period End2020-03-31
Value0.094
Percentage of PublicUtilitiesRequestedReturnOnEquityPercentage89.5

us-gaap:RelatedPartyTransaction, dei:LegalEntity

us-gaap:RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value30121053
Percentage of RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty100.00.0100.0100.0100.00.0100.0100.0

aee:AmerenIllinoistransmissionagreementswithATXI, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value1000000.01000000.01000000.01000000.01000000.00.01000000.01000000.0
Percentage of RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty33.30.0100.050.0100.00.020.033.3

aee:AmerenMissouriAndAmerenIllinoisRentAndFacilityServices, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value11121211
Percentage of RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty33.30.0100.0100.0100.00.020.033.3

aee:AmerenServicesSupportServicesAgreement, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value3336303130333330
Percentage of RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty1100.00.03000.01550.03000.00.0660.01000.0

aee:AmerenServicesSupportServicesAgreement, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value3537343232353632
Percentage of RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty1166.70.03400.01600.03200.00.0720.01066.7

aee:PurchasedPower, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value31221054
Percentage of RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty100.00.0200.0100.0100.00.0100.0133.3

aee:TotalRelatedPartyOtherOperationsandMaintenance, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value3437313331353431
Percentage of RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty1133.30.03100.01650.03100.00.0680.01033.3

aee:TotalRelatedPartyOtherOperationsandMaintenance, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value3538343332363732
Percentage of RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty1166.70.03400.01650.03200.00.0740.01066.7

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us-gaap:RevenueFromRelatedParties

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Period End2020-03-312019-03-31
Value1315
Percentage of RevenueFromRelatedParties100.0100.0

us-gaap:OperatingSegments, aee:UnionElectricCompany, us-gaap:IntersubsegmentEliminations



Period End2020-03-312019-03-31
Value107
Percentage of RevenueFromRelatedParties76.946.7

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Period End2020-03-312019-03-31
Value1215
Percentage of RevenueFromRelatedParties92.3100.0

us-gaap:ConsolidationItems, us-gaap:SubsegmentsConsolidationItems

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Period End2020-03-312019-03-31
Value-24-23
Percentage of RevenueFromRelatedParties-184.6-153.3

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us-gaap:IntersegmentElimination, us-gaap:IntersubsegmentEliminations, aee:AmerenIllinoisCompany



Period End2020-03-312019-03-31
Value-12-15
Percentage of RevenueFromRelatedParties-92.3-100.0

us-gaap:RelatedPartyTransaction, dei:LegalEntity

aee:AmerenMissouriAndAmerenIllinoisRentAndFacilityServices, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value1000000.00.01000000.01000000.01000000.01000000.01000000.01000000.0
Percentage of RevenueFromRelatedParties7.70.00.00.06.70.00.00.0

aee:AmerenMissouriAndAmerenIllinoisRentAndFacilityServices, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value77767566
Percentage of RevenueFromRelatedParties53.80.00.00.046.70.00.00.0

aee:AmerenMissouriPowerSupplyAgreementsWithAmerenIllinois, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value30121053
Percentage of RevenueFromRelatedParties23.10.00.00.06.70.00.00.0

aee:TotalRelatedPartyOperatingRevenues, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value112011211
Percentage of RevenueFromRelatedParties7.70.00.00.06.70.00.00.0

aee:TotalRelatedPartyOperatingRevenues, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value1079876119
Percentage of RevenueFromRelatedParties76.90.00.00.046.70.00.00.0

us-gaap:ShortTermDebtType

us-gaap:ShortTermDebtWeightedAverageInterestRateOverTime

aee:Utilities



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-30
Value0.01930.0240.02750.02870.020.02170.0190.01240.0127
Percentage of ShortTermDebtWeightedAverageInterestRateOverTime100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DebtInstrument, us-gaap:ShortTermDebtType

us-gaap:ShorttermDebtAverageOutstandingAmount

aee:IllinoisCreditAgreement, us-gaap:LineOfCredit



Period End2020-03-31
Value7
Percentage of ShorttermDebtAverageOutstandingAmount100.0

aee:MissouriCreditAgreement, us-gaap:LineOfCredit



Period End2020-03-31
Value13
Percentage of ShorttermDebtAverageOutstandingAmount185.7

us-gaap:DebtInstrument, us-gaap:ShortTermDebtType, dei:LegalEntity

aee:IllinoisCreditAgreement, us-gaap:LineOfCredit, aee:AmerenIllinoisCompany



Period End2020-03-31
Value5
Percentage of ShorttermDebtAverageOutstandingAmount71.4

aee:IllinoisCreditAgreement, us-gaap:LineOfCredit, aee:AmerenparentDomain



Period End2020-03-31
Value2
Percentage of ShorttermDebtAverageOutstandingAmount28.6

aee:IllinoisCreditAgreement, us-gaap:LineOfCredit, aee:UnionElectricCompany



Period End2020-03-31
Value0.0
Percentage of ShorttermDebtAverageOutstandingAmount0.0

aee:MissouriCreditAgreement, us-gaap:LineOfCredit, aee:AmerenIllinoisCompany



Period End2020-03-31
Value0.0
Percentage of ShorttermDebtAverageOutstandingAmount0.0

aee:MissouriCreditAgreement, us-gaap:LineOfCredit, aee:AmerenparentDomain



Period End2020-03-31
Value1000000.0
Percentage of ShorttermDebtAverageOutstandingAmount14.3

aee:MissouriCreditAgreement, us-gaap:LineOfCredit, aee:UnionElectricCompany



Period End2020-03-31
Value12
Percentage of ShorttermDebtAverageOutstandingAmount171.4

us-gaap:ShortTermDebtType

us-gaap:CommercialPaper



Period End2020-03-312019-03-312013-03-312012-03-31
Value608815284
Percentage of ShorttermDebtAverageOutstandingAmount8685.70.00.00.0

us-gaap:ShortTermDebtType, dei:LegalEntity

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Period End2020-03-312019-03-31
Value7189
Percentage of ShorttermDebtAverageOutstandingAmount1014.30.0

us-gaap:CommercialPaper, aee:AmerenparentDomain



Period End2020-03-312019-03-31
Value154480
Percentage of ShorttermDebtAverageOutstandingAmount2200.00.0

us-gaap:CommercialPaper, aee:UnionElectricCompany



Period End2020-03-312019-03-31
Value383246
Percentage of ShorttermDebtAverageOutstandingAmount5471.40.0

us-gaap:DebtInstrument, us-gaap:ShortTermDebtType

us-gaap:ShorttermDebtMaximumAmountOutstandingDuringPeriod

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Period End2020-03-31
Value235
Percentage of ShorttermDebtMaximumAmountOutstandingDuringPeriod100.0

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Period End2020-03-31
Value230
Percentage of ShorttermDebtMaximumAmountOutstandingDuringPeriod97.9

us-gaap:DebtInstrument, us-gaap:ShortTermDebtType, dei:LegalEntity

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Period End2020-03-31
Value60
Percentage of ShorttermDebtMaximumAmountOutstandingDuringPeriod25.5

aee:IllinoisCreditAgreement, us-gaap:LineOfCredit, aee:AmerenparentDomain



Period End2020-03-31
Value175
Percentage of ShorttermDebtMaximumAmountOutstandingDuringPeriod74.5

aee:IllinoisCreditAgreement, us-gaap:LineOfCredit, aee:UnionElectricCompany



Period End2020-03-31
Value0.0
Percentage of ShorttermDebtMaximumAmountOutstandingDuringPeriod0.0

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Period End2020-03-31
Value0.0
Percentage of ShorttermDebtMaximumAmountOutstandingDuringPeriod0.0

aee:MissouriCreditAgreement, us-gaap:LineOfCredit, aee:AmerenparentDomain



Period End2020-03-31
Value100
Percentage of ShorttermDebtMaximumAmountOutstandingDuringPeriod42.6

aee:MissouriCreditAgreement, us-gaap:LineOfCredit, aee:UnionElectricCompany



Period End2020-03-31
Value130
Percentage of ShorttermDebtMaximumAmountOutstandingDuringPeriod55.3

us-gaap:ShortTermDebtType

us-gaap:CommercialPaper



Period End2020-03-312019-03-312013-03-312012-03-31
Value854111321186
Percentage of ShorttermDebtMaximumAmountOutstandingDuringPeriod363.40.00.00.0

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Period End2020-03-312019-03-31
Value137130
Percentage of ShorttermDebtMaximumAmountOutstandingDuringPeriod58.30.0

us-gaap:CommercialPaper, aee:AmerenparentDomain



Period End2020-03-312019-03-31
Value225618
Percentage of ShorttermDebtMaximumAmountOutstandingDuringPeriod95.70.0

us-gaap:CommercialPaper, aee:UnionElectricCompany



Period End2020-03-312019-03-31
Value521549
Percentage of ShorttermDebtMaximumAmountOutstandingDuringPeriod221.70.0

us-gaap:StockIssued1



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value3800054000350000
Percentage of StockIssued1100.00.00.00.0100.00.00.00.0100.00.00.00.00.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312018-03-312011-09-302011-06-30
Value200000.0200000.0200000.0200000.0300000.0300000.0200000.0400000.0700000.0300000.0600000.0600000.0
Percentage of StockIssuedDuringPeriodSharesNewIssues100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StockIssuedDuringPeriodSharesOther



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value500000.00.00.00.0800000.00.00.00.0700000.0
Percentage of StockIssuedDuringPeriodSharesOther100.00.00.00.0100.00.00.00.0100.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value131417181918162317
Percentage of StockIssuedDuringPeriodValueNewIssues100.0100.0100.0100.0100.0100.0100.0100.0100.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value125106131118126109127122125113129117118109129115114104128116125106121114127121111122119116121121109125119102121
Percentage of TaxesExcludingIncomeAndExciseTaxes100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value423333324536323541363328403430303829292943293132463030422431392926412924
Percentage of TaxesExcludingIncomeAndExciseTaxes33.631.125.227.135.733.025.228.732.831.925.623.933.931.223.326.133.327.922.725.034.427.425.628.136.224.827.034.420.226.732.224.023.932.824.423.5

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value797396837771948480739585757396837373978580748981789179778778718576738268
Percentage of TaxesExcludingIncomeAndExciseTaxes63.268.973.370.361.165.174.068.964.064.673.672.663.667.074.472.264.070.275.873.364.069.873.671.161.475.271.263.173.167.258.770.269.758.468.966.7

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Period End2020-03-312019-03-31
Value255248
Percentage of UtilitiesOperatingExpenseDepreciationAndAmortization100.0100.0

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aee:AmerenIllinoisCompany



Period End2020-03-312019-03-31
Value107101
Percentage of UtilitiesOperatingExpenseDepreciationAndAmortization42.040.7

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Period End2020-03-312019-03-31
Value139140
Percentage of UtilitiesOperatingExpenseDepreciationAndAmortization54.556.5

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Period End2020-03-312019-03-31
Value140160
Percentage of UtilitiesOperatingExpenseFuelUsed100.0100.0

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Period End2020-03-312019-03-31
Value140160
Percentage of UtilitiesOperatingExpenseFuelUsed100.0100.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value10795314416112230511711152541
Percentage of UtilitiesOperatingExpenseGasAndPetroleumPurchased100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value898325361341032543147972136
Percentage of UtilitiesOperatingExpenseGasAndPetroleumPurchased83.287.480.681.883.284.483.384.386.084.384.087.8

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value181268271958241845
Percentage of UtilitiesOperatingExpenseGasAndPetroleumPurchased16.812.619.418.216.815.616.715.714.015.716.012.2

us-gaap:UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value438444434450417473429439431431402422405430411435400438428427401455404412420383447399424458427432475463455465
Percentage of UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

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Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value199202193196191209195196199199183210197212198200194191202202202191185195200166196176159186168152181168155159
Percentage of UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses45.445.544.543.645.844.245.544.646.246.245.549.848.649.348.246.048.543.647.247.350.442.045.847.347.643.343.844.137.540.639.335.238.136.334.134.2

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value239240242254224265234241232247224219212223220238212252233229211269228222227212253221203206202218231233233240
Percentage of UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses54.654.155.856.453.756.054.554.953.857.355.751.952.351.953.554.753.057.554.453.652.659.156.453.954.055.456.655.447.945.047.350.548.650.351.251.6

us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity

aee:FinalRateOrder, us-gaap:Electricity, aee:UnionElectricCompany



Period End2020-03-31
Value60
Percentage of UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses13.7

us-gaap:UtilitiesOperatingExpensePurchasedPower



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value134116148136156128148142163145163150
Percentage of UtilitiesOperatingExpensePurchasedPower100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value9884101781059510510512410512487
Percentage of UtilitiesOperatingExpensePurchasedPower73.172.468.257.467.374.270.973.976.172.476.158.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value393349605133494042424369
Percentage of UtilitiesOperatingExpensePurchasedPower29.128.433.144.132.725.833.128.225.829.026.446.0

us-gaap:PublicUtilitiesRegulatoryProceeding, us-gaap:PublicUtility, dei:LegalEntity

aee:FinalRateOrder, us-gaap:Electricity, aee:UnionElectricCompany



Period End2020-03-31
Value15
Percentage of UtilitiesOperatingExpensePurchasedPower11.2

aee:Corporateownedlifeinsuranceborrowings



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value109114114118113113113107111120
Percentage of Corporateownedlifeinsuranceborrowings100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value109114118118113113113111111120
Percentage of Corporateownedlifeinsuranceborrowings100.0100.0103.5100.0100.0100.0100.0103.7100.0100.0

aee:DefinedBenefitPlanEstimatedFutureEmployerContributionsOverNextFiveYears



Period End2020-03-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312012-03-312011-12-31
Value11570200120290280290270550580580
Percentage of DefinedBenefitPlanEstimatedFutureEmployerContributionsOverNextFiveYears100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Range

srt:Maximum



Period End2020-03-312019-12-312018-12-31
Value454570
Percentage of DefinedBenefitPlanEstimatedFutureEmployerContributionsOverNextFiveYears39.164.335.0

srt:Minimum



Period End2020-03-312018-12-31
Value520
Percentage of DefinedBenefitPlanEstimatedFutureEmployerContributionsOverNextFiveYears4.310.0

us-gaap:Range

aee:Estimatedcapitalcoststocomplywithexistingandknownfederalandstateairemissionstandards.

srt:Maximum



Period End2020-03-312019-09-30
Value250400
Percentage of Estimatedcapitalcoststocomplywithexistingandknownfederalandstateairemissionstandards.100.0100.0

srt:Minimum



Period End2020-03-312019-09-30
Value200300
Percentage of Estimatedcapitalcoststocomplywithexistingandknownfederalandstateairemissionstandards.80.075.0

us-gaap:Range, dei:LegalEntity

srt:Maximum, aee:UnionElectricCompany



Period End2020-03-312019-09-30
Value250400
Percentage of Estimatedcapitalcoststocomplywithexistingandknownfederalandstateairemissionstandards.100.0100.0

srt:Minimum, aee:UnionElectricCompany



Period End2020-03-312019-09-30
Value200300
Percentage of Estimatedcapitalcoststocomplywithexistingandknownfederalandstateairemissionstandards.80.075.0

us-gaap:Range, us-gaap:LossContingenciesByNatureOfContingency, dei:LegalEntity

srt:Maximum, aee:CoalCombustionResidualsEstimate, aee:UnionElectricCompany



Period End2020-03-312019-09-30
Value125200
Percentage of Estimatedcapitalcoststocomplywithexistingandknownfederalandstateairemissionstandards.50.050.0

srt:Minimum, aee:CoalCombustionResidualsEstimate, aee:UnionElectricCompany



Period End2020-03-312019-09-30
Value75150
Percentage of Estimatedcapitalcoststocomplywithexistingandknownfederalandstateairemissionstandards.30.037.5

us-gaap:LossContingenciesByNatureOfContingency

aee:InsuranceAggregateMaximumCoverage

aee:Nonradiationevent



Period End2020-04-012019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-31
Value23002300230023002300230023002300230023002300230023002300230023002300225022502250
Percentage of InsuranceAggregateMaximumCoverage100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

aee:PropertyDamageEuropeanMutualAssociationforNuclearInsurance



Period End2020-04-012019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-30
Value490490490490490490490490490490490490490450450450450500500500500500500500500500500
Percentage of InsuranceAggregateMaximumCoverage21.321.321.321.321.321.321.321.321.321.321.321.321.319.619.619.619.60.022.222.222.20.00.00.00.00.00.0

aee:PropertyDamageNuclearElectricInsuranceLtd



Period End2020-04-012019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value3200320032003200320032003200320032003200320032003200271027502750275027502750275027502250225022502250225022502750275027502750275027502750
Percentage of InsuranceAggregateMaximumCoverage139.1139.1139.1139.1139.1139.1139.1139.1139.1139.1139.1139.1139.1117.8119.6119.6119.60.0122.2122.2122.20.00.00.00.00.00.00.00.00.00.00.00.00.0

aee:PublicLiability



Period End2020-04-012019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-30
Value1379813936139361393614073140731407313054130541343613436134361343613361133611348913361133611361613616136161361613687
Percentage of InsuranceAggregateMaximumCoverage599.9605.9605.9605.9611.9611.9611.9567.6567.6584.2584.2584.2584.2580.9580.9586.5593.8593.8605.20.00.00.00.0

aee:PublicLiabilityAndNuclearWorkerLiabilityAmericanNuclearInsurers



Period End2020-04-012019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value450450450450450450450450450450450450450375375375375375375375375375375375375375375375375375375375375375
Percentage of InsuranceAggregateMaximumCoverage19.619.619.619.619.619.619.619.619.619.619.619.619.616.316.316.316.30.016.716.716.70.00.00.00.00.00.00.00.00.00.00.00.00.0

aee:PublicLiabilityAndNuclearWorkerLiabilityPoolParticipation



Period End2020-04-012019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value13348134861348613486136231362313623126041260412986129861298612986129861298612986131141311412986129861324113241132411324113241132411331212219122191221912219122191221912219
Percentage of InsuranceAggregateMaximumCoverage580.3586.3586.3586.3592.3592.3592.3548.0548.0564.6564.6564.6564.6564.6564.6564.6570.20.0577.2577.2588.50.00.00.00.00.00.00.00.00.00.00.00.00.0

aee:RadiationEvent



Period End2020-04-012019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value27002700270027002700270027002700270027002700270027002710275027502250500500500500
Percentage of InsuranceAggregateMaximumCoverage117.4117.4117.4117.4117.4117.4117.4117.4117.4117.4117.4117.4117.4117.8119.6119.697.80.022.222.222.2

us-gaap:LossContingenciesByNatureOfContingency

aee:InsuranceMaximumCoveragePerIncident

aee:PropertyDamageNuclearElectricInsuranceLtd



Period End2020-04-012019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value25272828282727272730292929303030302727272623232323232323232323232323
Percentage of InsuranceMaximumCoveragePerIncident100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

aee:PublicLiability



Period End2020-04-012019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-30
Value138138138138138138138127127127127127127127127127127128128128128128128
Percentage of InsuranceMaximumCoveragePerIncident552.0511.1492.9492.9492.9511.1511.1470.4470.4423.3437.9437.9437.9423.3423.3423.3470.4474.1492.3556.5556.5556.5556.5

aee:PublicLiabilityAndNuclearWorkerLiabilityPoolParticipation



Period End2020-04-012019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value138138138138138138138127127127127127127127127127127127127128128128128128128128128118118118118118118118
Percentage of InsuranceMaximumCoveragePerIncident552.0511.1492.9492.9492.9511.1511.1470.4470.4423.3437.9437.9437.9423.3423.3423.3423.3470.4470.4474.1492.3556.5556.5556.5556.5556.5556.5513.0513.0513.0513.0513.0513.0513.0

aee:ReplacementPowerNuclearElectricInsuranceLtd



Period End2020-04-012019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value7777777777777777710101099999999999999
Percentage of InsuranceMaximumCoveragePerIncident28.025.925.025.025.025.925.925.925.923.324.124.124.123.323.323.323.337.037.037.034.639.139.139.139.139.139.139.139.139.139.139.139.139.1

aee:Payablesforpurchasedreceivables



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value33323734383340403331
Percentage of Payablesforpurchasedreceivables100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

aee:ReceivablesPayablesAndAccruedIncomeNet



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value16589656642222221-1-1-222123229-1-11111
Percentage of ReceivablesPayablesAndAccruedIncomeNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302014-12-31
Value8586646644222-1221-1-12
Percentage of ReceivablesPayablesAndAccruedIncomeNet50.0100.0100.066.7100.080.0100.0100.0100.0200.00.0100.0100.0-50.0100.0100.0100.0100.0100.0100.0

aee:RestrictedCashandCashEquivalentsNuclearDecommissioningTrustFund



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-31
Value172610137434322111
Percentage of RestrictedCashandCashEquivalentsNuclearDecommissioningTrustFund100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-31
Value172610137434322111
Percentage of RestrictedCashandCashEquivalentsNuclearDecommissioningTrustFund100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:EntityCommonStockSharesOutstanding



Period End2020-04-302020-01-312019-10-312019-07-312019-04-302019-01-312018-10-312018-07-312018-04-302018-01-312017-10-312017-07-312017-04-282017-01-312016-10-312016-07-292016-04-292016-01-292015-10-302015-07-312015-04-302015-01-302014-09-302014-06-302014-04-302014-01-312013-10-312013-07-312013-04-302013-01-312012-10-312012-07-31
Value246246246245245244244244243242242242242242242242242242242242242242242242242242242242242242242242
Percentage of EntityCommonStockSharesOutstanding100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

us-gaap:AccountsPayableRelatedPartiesCurrent

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value848267556358444459705055576359435566364349502825281886917486827698103586582
Percentage of AccountsPayableRelatedPartiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value48521267669699012540601021225468894059563543595632163830611036566546210773485575
Percentage of AccountsPayableRelatedPartiesCurrent57.163.4188.1138.2109.5119.0204.5284.167.885.7204.0221.894.7107.9150.893.0107.384.897.2100.0120.4112.0114.364.0135.7166.770.9113.287.876.765.981.6109.270.982.884.691.5

us-gaap:RelatedPartyTransaction, dei:LegalEntity

aee:Incometaxespayabletoparent, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302018-12-31
Value4843247
Percentage of AccountsPayableRelatedPartiesCurrent57.152.435.812.1

aee:Incometaxespayabletoparent, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302018-12-31
Value12155816
Percentage of AccountsPayableRelatedPartiesCurrent14.318.386.627.6

dei:LegalEntity

us-gaap:AccountsReceivableRelatedPartiesCurrent

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value15283837182136211192169101013151022185222028131310910121592173
Percentage of AccountsReceivableRelatedPartiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value3430202120141623141114151512201516548133651221193643311106
Percentage of AccountsReceivableRelatedPartiesCurrent226.7107.152.656.8111.166.744.4109.5127.3122.266.721.7150.0120.0153.8100.0160.0245.5800.0162.560.0295.5600.00.00.00.032.123.146.240.033.325.06.711.147.68.2

us-gaap:RelatedPartyTransaction, dei:LegalEntity

aee:Incometaxesreceivablefromparent, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302018-12-31
Value11706
Percentage of AccountsReceivableRelatedPartiesCurrent6.760.70.028.6

aee:Incometaxesreceivablefromparent, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302018-12-31
Value161500
Percentage of AccountsReceivableRelatedPartiesCurrent106.753.60.00.0

us-gaap:LossContingenciesByNatureOfContingency

us-gaap:AccrualForEnvironmentalLossContingencies

aee:ManufacturedGasPlant



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-30
Value126129145145145150162165168175184188193200204217224232237245245250254259269278251256259257133102102107112121
Percentage of AccrualForEnvironmentalLossContingencies100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LossContingenciesByNatureOfContingency, dei:LegalEntity

aee:ManufacturedGasPlant, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-30
Value126129139145
Percentage of AccrualForEnvironmentalLossContingencies100.0100.095.9100.0

dei:LegalEntity

us-gaap:AccruedEnvironmentalLossContingenciesCurrent

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value52425644454250434742433742383535382835434652534746435356443738322563575572
Percentage of AccruedEnvironmentalLossContingenciesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

us-gaap:AccruedEnvironmentalLossContingenciesNoncurrent

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-31
Value758785102101109113123122134143152152162171183187205203198200199202212222232194196211216
Percentage of AccruedEnvironmentalLossContingenciesNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AdditionalPaidInCapital



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value569556945673564956255627559855765546554055345528552255565550554555395616561256065600561756125607560256325624561956145616561156005596559855805559554055205412
Percentage of AdditionalPaidInCapital100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value2288218821732173217321732093209320332013200520052005200520052005200520051980198019801980196519651965196519651965196519651965196519651965195219521952
Percentage of AdditionalPaidInCapital40.238.438.338.538.638.637.437.536.736.336.236.336.336.136.136.236.235.735.335.335.435.335.035.035.134.934.935.035.035.035.035.135.135.135.035.135.4

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value2027202719031903190319031858185818581858182818281828182818241822182218221784178417841569156015601560156015561556155615561555155515551555155515551555
Percentage of AdditionalPaidInCapital35.635.633.533.733.833.833.233.333.533.533.033.133.132.932.932.932.932.431.831.831.927.927.827.827.827.727.727.727.727.727.727.827.827.827.928.028.2

us-gaap:AllowanceForDoubtfulAccountsReceivable



Period End2020-03-312019-12-312019-03-312018-12-31
Value19171918
Percentage of AllowanceForDoubtfulAccountsReceivable100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-03-312018-12-31
Value11101211
Percentage of AllowanceForDoubtfulAccountsReceivable57.958.863.261.1

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-03-312018-12-31
Value8777
Percentage of AllowanceForDoubtfulAccountsReceivable42.141.236.838.9

us-gaap:AllowanceForDoubtfulAccountsReceivableCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value191719191918222520192021191919212119202123212123261820222217242424202125332324
Percentage of AllowanceForDoubtfulAccountsReceivableCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value11101112121114161312121313121214151213131513141618131316141217161613131613
Percentage of AllowanceForDoubtfulAccountsReceivableCurrent57.958.857.963.263.261.163.664.065.063.260.061.968.463.263.266.771.463.265.061.965.261.966.769.669.272.265.072.763.670.670.866.766.765.061.964.056.5

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value8787778977886777677788777576858797788
Percentage of AllowanceForDoubtfulAccountsReceivableCurrent42.141.242.136.836.838.936.436.035.036.840.038.131.636.836.833.328.636.835.033.334.838.133.330.426.927.835.027.336.429.433.329.237.535.033.332.034.8

us-gaap:AssetRetirementObligation



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-312015-12-312015-09-302015-06-302015-03-312014-12-312013-12-312013-09-302012-12-312012-09-302011-12-312011-09-302010-12-312009-12-312008-12-31
Value684691694690653650646647642644646649650623597589500396369392453437433445475434411
Percentage of AssetRetirementObligation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-312015-12-312015-09-302015-06-302015-03-312014-12-312013-12-312013-09-302012-12-312012-09-302011-12-312010-12-31
Value444444444445667777333333
Percentage of AssetRetirementObligation0.60.60.60.60.60.60.60.60.60.60.60.80.91.01.21.21.41.80.80.80.70.70.70.6

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-312015-12-312015-09-302015-06-302015-03-312014-12-312013-12-312013-09-302012-12-312011-12-312010-12-31
Value680687690686649646642643638640642644644617590582493389366362346328363
Percentage of AssetRetirementObligation99.499.499.499.499.499.499.499.499.499.499.499.299.199.098.898.898.698.299.292.376.475.876.4

us-gaap:RealEstateAndAccumulatedDepreciationDescriptionOfProperty

aee:NewCCRRulesEstimate



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-12-31
Value137151162162131135141141150
Percentage of AssetRetirementObligation20.021.923.323.520.120.921.822.023.3

us-gaap:RealEstateAndAccumulatedDepreciationDescriptionOfProperty, dei:LegalEntity

aee:NewCCRRulesEstimate, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-30
Value137151160162
Percentage of AssetRetirementObligation20.021.923.123.5

us-gaap:AssetRetirementObligationsNoncurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value631638671667630627640641636638631634641635636629625618597589500396385380373369392385380445429440434428439487482475429
Percentage of AssetRetirementObligationsNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value627634667663626623636637632634627629635629630623619612590582493389383378371366362355351346342337333328334373363
Percentage of AssetRetirementObligationsNoncurrent99.499.499.499.499.499.499.499.499.499.499.499.299.199.199.199.099.099.098.898.898.698.299.599.599.599.292.392.292.477.879.776.676.776.676.176.676.4

us-gaap:AssetsFairValueDisclosure



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value756868811804765694767730708719688667645632612601573575559588565566543555529528499497471568606622596
Percentage of AssetsFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312011-12-31
Value752864808800759691765728707719686665640619609596572574559587564565541551524527499493462434413
Percentage of AssetsFairValueDisclosure99.599.599.699.599.299.699.799.799.9100.099.799.799.297.999.599.299.899.8100.099.899.899.899.699.399.199.8100.099.298.176.469.3

us-gaap:FairValueByFairValueHierarchyLevel

us-gaap:FairValueInputsLevel1



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value461569519513490428505489470474450429423413396380371368341376370365349348330336312297300276294268274
Percentage of AssetsFairValueDisclosure61.065.664.063.864.161.765.867.066.465.965.464.365.665.364.763.264.764.061.063.965.564.564.362.762.463.662.559.863.748.648.543.146.0

us-gaap:FairValueInputsLevel2



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value270276272264263255250228231233226222216208204206196190195182188187180181179163149147149152158166123
Percentage of AssetsFairValueDisclosure35.731.833.532.834.436.732.631.232.632.432.833.333.532.933.334.334.233.034.931.033.333.033.132.633.830.929.929.631.626.826.126.720.6

us-gaap:FairValueInputsLevel3



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value252320271211121371212166111215617233071414262029385322140154188199
Percentage of AssetsFairValueDisclosure3.32.62.53.41.61.61.61.81.01.71.72.40.91.72.02.51.03.04.15.11.22.52.64.73.85.57.610.74.724.625.430.233.4

us-gaap:FairValueByFairValueHierarchyLevel, dei:LegalEntity

us-gaap:FairValueInputsLevel1, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value461569519513428
Percentage of AssetsFairValueDisclosure61.065.664.063.861.7

us-gaap:FairValueInputsLevel2, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value269275272263253
Percentage of AssetsFairValueDisclosure35.631.733.532.736.5

us-gaap:FairValueInputsLevel3, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value2220172410
Percentage of AssetsFairValueDisclosure2.92.32.13.01.4

us-gaap:CashSurrenderValueOfLifeInsurance



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value245264258262258244256249251265
Percentage of CashSurrenderValueOfLifeInsurance100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value118123121125123122120117120129
Percentage of CashSurrenderValueOfLifeInsurance48.246.646.947.747.750.046.947.047.848.7

dei:LegalEntity

us-gaap:ContractWithCustomerLiabilityCurrent

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302017-12-31
Value8077717173768469
Percentage of ContractWithCustomerLiabilityCurrent100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DecommissioningFundInvestments



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value742847798783754684752714698704672651635607599582567556534555558549529523503494459442437408407386390357330356353337293
Percentage of DecommissioningFundInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

dei:LegalEntity

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value742847798783754684752714698704672651635607599582567556534555558549529523503494459442437408407386390357330356337
Percentage of DecommissioningFundInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DecommissioningTrustAssetsAmount



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value726842790774748679746708694702672649633605597580566557535557556547527521501494458440434406409395358
Percentage of DecommissioningTrustAssetsAmount100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredCompensationLiabilityClassifiedNoncurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value85867878788086858486
Percentage of DeferredCompensationLiabilityClassifiedNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FairValueByMeasurementBasis

us-gaap:DeferredFinanceCostsNet

us-gaap:CarryingReportedAmountFairValueDisclosure



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value73726562625856564950
Percentage of DeferredFinanceCostsNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FairValueByMeasurementBasis, dei:LegalEntity

us-gaap:CarryingReportedAmountFairValueDisclosure, aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value3434313131
Percentage of DeferredFinanceCostsNet46.647.247.750.053.4

us-gaap:CarryingReportedAmountFairValueDisclosure, aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value3230272622
Percentage of DeferredFinanceCostsNet43.841.741.541.937.9

us-gaap:DeferredIncomeTaxesAndOtherTaxLiabilitiesNoncurrent



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value29482919290227582666
Percentage of DeferredIncomeTaxesAndOtherTaxLiabilitiesNoncurrent100.0100.0100.0100.0100.0

dei:LegalEntity

aee:AmerenIllinoisCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value12511224118011751119
Percentage of DeferredIncomeTaxesAndOtherTaxLiabilitiesNoncurrent42.441.940.742.642.0

aee:UnionElectricCompany



Period End2020-03-312019-12-312019-09-302019-06-302018-12-31
Value16271612161915961576
Percentage of DeferredIncomeTaxesAndOtherTaxLiabilitiesNoncurrent55.255.255.857.959.1

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us-gaap:DerivativeAssetLiabilityNetMeasurementInput

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Period End2020-03-312019-12-312018-09-302018-06-302018-03-312017-09-302017-06-30
Value33.034.039.039.039.046.046.0
Percentage of DerivativeAssetLiabilityNetMeasurementInput100.0100.0100.0100.0100.0100.0100.0

srt:Maximum, aee:Power, us-gaap:MeasurementInputCommodityFuturePrice, aee:DiscountedCashFlow



Period End2020-03-312019-12-31
Value3.00.0
Percentage of DerivativeAssetLiabilityNetMeasurementInput9.10.0

srt:Minimum, aee:Power, aee:MeasurementInputNodalBasis, aee:DiscountedCashFlow



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-30
Value-6.0-6.0-7.0-9.0-9.0-10.0-10.0-9.0-10.0-10.0
Percentage of DerivativeAssetLiabilityNetMeasurementInput-18.2-17.60.00.00.0-25.6-25.6-23.1-21.7-21.7

srt:Minimum, aee:Power, us-gaap:MeasurementInputCommodityForwardPrice, aee:DiscountedCashFlow