1.0.0.3 false CONSOLIDATED BALANCE SHEETS (Parenthetical) (Constellation Energy Group, Inc. and Subsidiaries) (USD $) In Millions false 1 $ false false usd Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 2 $ false false usd Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 2 BALANCE SHEETS 0 us-gaap_StatementOfFinancialPositionAbstract 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 No definition available. false 3 Allowance for uncollectibles 1 us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 true true 260200000 260.2 false false 2 true true 240600000 240.6 false false No definition available. No authoritative reference available. false false 2 2 false HundredThousands UnKnown UnKnown false true