1.0.0.3 false CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Constellation Energy Group, Inc. and Subsidiaries) (USD $) In Millions false 1 $ false false shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 usd Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 usdPerShare Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 2 $ false false shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 usd Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 usdPerShare Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 3 $ false false shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 usd Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 usdPerShare Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 4 $ false false shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 usd Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 usdPerShare Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 4 Net Income (Loss) 2 us-gaap_ProfitLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 28300000 28.3 false false 2 true true 175000000 175.0 false false 3 true true -91400000 -91.4 false false 4 true true 324400000 324.4 false false No definition available. No authoritative reference available. false 6 Hedging instruments: 3 us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecreaseAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 7 Reclassificiation of net loss (gain) on hedging instruments from OCI to net income (loss), net of taxes 4 us-gaap_OtherComprehensiveIncomeReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 399500000 399.5 false false 2 false true -99000000 -99.0 false false 3 false true 859400000 859.4 false false 4 false true 78000000 78.0 false false No definition available. No authoritative reference available. false 8 Net unrealized (loss) gain on hedging instruments, net of taxes 4 us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -48700000 -48.7 false false 2 false true 511800000 511.8 false false 3 false true -384900000 -384.9 false false 4 false true 873400000 873.4 false false No definition available. No authoritative reference available. false 9 Available-for-sale securities: 3 us-gaap_OtherComprehensiveIncomeAvailableForSaleSecuritiesAdjustmentNetOfTaxPeriodIncreaseDecreaseAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 10 Reclassification of net (gain) loss on sales of securities from OCI to net income (loss), net of taxes 4 us-gaap_OtherComprehensiveIncomeReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTax us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -200000 -0.2 false false 2 false true 1900000 1.9 false false 3 false true 29500000 29.5 false false 4 false true 1600000 1.6 false false No definition available. No authoritative reference available. false 11 Net unrealized gain (loss) on securities, net of taxes 4 us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 45600000 45.6 false false 2 false true 16400000 16.4 false false 3 false true 18900000 18.9 false false 4 false true -28700000 -28.7 false false No definition available. No authoritative reference available. false 12 Defined benefit obligations: 3 us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPeriodIncreaseDecreaseAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 13 Amortization of net actuarial loss, prior service cost, and transition obligation included in net periodic benefit cost, net of taxes 4 us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true 14200000 14.2 false false 2 false true 5400000 5.4 false false 3 false true 22100000 22.1 false false 4 false true 10500000 10.5 false false No definition available. No authoritative reference available. false 14 Net unrealized gain (loss) on foreign currency, net of taxes 3 us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true 2500000 2.5 false false 2 false true 2100000 2.1 false false 3 false true 4500000 4.5 false false 4 false true -400000 -0.4 false false No definition available. No authoritative reference available. false 15 Comprehensive income 2 us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 441200000 441.2 false false 2 false true 613600000 613.6 false false 3 false true 458100000 458.1 false false 4 false true 1258800000 1258.8 false false No definition available. No authoritative reference available. true 16 Less: Comprehensive income attributable to noncontrolling interests, net of taxes 2 us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 20200000 20.2 false false 2 false true 3500000 3.5 false false 3 false true 24000000 24.0 false false 4 false true 7200000 7.2 false false No definition available. No authoritative reference available. false 17 Comprehensive Income Attributable to Common Stock 2 us-gaap_ComprehensiveIncomeNetOfTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 421000000 421.0 false false 2 true true 610100000 610.1 false false 3 true true 434100000 434.1 false false 4 true true 1251600000 1251.6 false false No definition available. No authoritative reference available. true false 4 13 false HundredThousands UnKnown UnKnown false true