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 167400000 167.4 false false 2 true true -222100000 -222.1 false false 3 true true 76000000 76.0 false false 4 true true 102300000 102.3 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 (loss) income, 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 358900000 358.9 false false 2 false true -166400000 -166.4 false false 3 false true 1218300000 1218.3 false false 4 false true -88400000 -88.4 false false No definition available. No authoritative reference available. false 8 Net unrealized loss 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 -29900000 -29.9 false false 2 false true -1059400000 -1059.4 false false 3 false true -414800000 -414.8 false false 4 false true -186000000 -186.0 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 (loss) income, 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 -2600000 -2.6 false false 2 false true 8900000 8.9 false false 3 false true 26900000 26.9 false false 4 false true 10500000 10.5 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 56700000 56.7 false false 2 false true -79100000 -79.1 false false 3 false true 75600000 75.6 false false 4 false true -107800000 -107.8 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 7400000 7.4 false false 2 false true 5400000 5.4 false false 3 false true 29500000 29.5 false false 4 false true 15900000 15.9 false false No definition available. No authoritative reference available. false 14 Net unrealized gain 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 2400000 2.4 false false 2 false true 500000 0.5 false false 3 false true 6900000 6.9 false false 4 false true 100000 0.1 false false No definition available. No authoritative reference available. false 15 Comprehensive income (loss) 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 560300000 560.3 false false 2 false true -1512200000 -1512.2 false false 3 false true 1018400000 1018.4 false false 4 false true -253400000 -253.4 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 29800000 29.8 false false 2 false true 3600000 3.6 false false 3 false true 53800000 53.8 false false 4 false true 10800000 10.8 false false No definition available. No authoritative reference available. false 17 Comprehensive Income (Loss) 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 530500000 530.5 false false 2 true true -1515800000 -1515.8 false false 3 true true 964600000 964.6 false false 4 true true -264200000 -264.2 false false No definition available. No authoritative reference available. true false 4 13 false HundredThousands UnKnown UnKnown false true