1.0.0.3 true Statement Of Other Comprehensive Income (USD $) In Millions false 1 $ true false false false PEPCO HOLDINGS INC dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_ParentCompanyMember dei_LegalEntityAxis explicitMember Shares Standard http://www.xbrl.org/2003/instance shares 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDperShareItemType Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares 0 false 2 $ true false false false PEPCO HOLDINGS INC dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_ParentCompanyMember dei_LegalEntityAxis explicitMember Shares Standard http://www.xbrl.org/2003/instance shares 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDperShareItemType Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares 0 false 3 $ true false false false PEPCO HOLDINGS INC dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_ParentCompanyMember dei_LegalEntityAxis explicitMember Shares Standard http://www.xbrl.org/2003/instance shares 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDperShareItemType Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares 0 false 4 $ true false false false PEPCO HOLDINGS INC dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_ParentCompanyMember dei_LegalEntityAxis explicitMember Shares Standard http://www.xbrl.org/2003/instance shares 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDperShareItemType Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares 0 1 PEPCO HOLDINGS INC 0 na true na na na No definition available. false true false false false false 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. No authoritative reference available. false 2 Net income 2 us-gaap_NetIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 25000000 25 false false 2 true true 15000000 15 false false 3 true true 70000000 70 false false 4 true true 114000000 114 false false No definition available. No authoritative reference available. false 3 Gains (losses) on commodity derivatives designated as cash flow hedges: 2 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 4 (Losses) gains arising during period 2 us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -26000000 -26 false false 2 false true 427000000 427 false false 3 false true -282000000 -282 false false 4 false true 639000000 639 false false No definition available. No authoritative reference available. false 5 Less: amount of (losses) gains reclassified into income 2 us-gaap_OtherComprehensiveIncomeReclassificationAdjustmentOnDerivativesIncludedInNetIncomeBeforeTax us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -108000000 -108 false false 2 false true 67000000 67 false false 3 false true -212000000 -212 false false 4 false true 82000000 82 false false No definition available. No authoritative reference available. false 6 Net gains (losses) on commodity derivatives 2 us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true 82000000 82 false false 2 false true 360000000 360 false false 3 false true -70000000 -70 false false 4 false true 557000000 557 false false No definition available. No authoritative reference available. true 7 Losses on Treasury Rate Locks reclassified into income 2 us-gaap_AmortizationOfDeferredHedgeGains us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 2000000 2 false false 2 false true 1000000 1 false false 3 false true 3000000 3 false false 4 false true 3000000 3 false false No definition available. No authoritative reference available. false 8 Amortization of gains and losses for prior service costs 2 us-gaap_DefinedBenefitPlanAmortizationOfNetPriorServiceCostCredit us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -10000000 -10 false false 2 false true -5000000 -5 false false 3 false true -10000000 -10 false false 4 false true -5000000 -5 false false No definition available. No authoritative reference available. false 9 Other comprehensive income (losses), before taxes 2 us-gaap_OtherComprehensiveIncomeLossBeforeTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true 74000000 74 false false 2 false true 356000000 356 false false 3 false true -77000000 -77 false false 4 false true 555000000 555 false false No definition available. No authoritative reference available. true 10 Income tax expense (benefit) 2 us-gaap_OtherComprehensiveIncomeLossTax us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 31000000 31 false false 2 false true 147000000 147 false false 3 false true -31000000 -31 false false 4 false true 227000000 227 false false No definition available. No authoritative reference available. false 11 Other comprehensive income (losses), net of income taxes 2 us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true 43000000 43 false false 2 false true 209000000 209 false false 3 false true -46000000 -46 false false 4 false true 328000000 328 false false No definition available. No authoritative reference available. true 12 Comprehensive income 2 us-gaap_ComprehensiveIncomeNetOfTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 68000000 68 false false 2 false true 224000000 224 false false 3 false true 24000000 24 false false 4 false true 442000000 442 false false No definition available. No authoritative reference available. true 13 POTOMAC ELECTRIC POWER CO 0 na true na na na No definition available. false true false false false false 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. No authoritative reference available. false 14 Net income 2 us-gaap_NetIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 17000000 17 false false 2 false true 31000000 31 false false 3 false true 36000000 36 false false 4 false true 46000000 46 false false No definition available. No authoritative reference available. false 25 DELMARVA POWER & LIGHT CO /DE/ 0 na true na na na No definition available. false true false false false false 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. No authoritative reference available. false 26 Net income 2 us-gaap_NetIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 5000000 5 false false 2 false true 16000000 16 false false 3 false true 26000000 26 false false 4 false true 42000000 42 false false No definition available. No authoritative reference available. false 37 ATLANTIC CITY ELECTRIC CO 0 na true na na na No definition available. false true false false false false 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. No authoritative reference available. false 38 Net income 2 us-gaap_NetIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 8000000 8 false false 2 true true 27000000 27 false false 3 true true 10000000 10 false false 4 true true 32000000 32 false false No definition available. No authoritative reference available. false false 4 18 false Millions UnKnown UnKnown false true