1.0.0.3 true Statement Of Income Alternative (USD $) In Millions, except Per Share data false 1 $ true false false false us-gaap_ParentCompanyMember 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 us-gaap_ParentCompanyMember 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 us-gaap_ParentCompanyMember 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 us-gaap_ParentCompanyMember 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 Operating Revenue 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 3 Power Delivery 2 us-gaap_UtilityRevenue us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 1095000000 1095 false false 2 true true 1297000000 1297 false false 3 true true 2467000000 2467 false false 4 true true 2592000000 2592 false false No definition available. No authoritative reference available. false 4 Competitive Energy 2 us-gaap_SalesRevenueFromEnergyCommoditiesAndServices us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 958000000 958 false false 2 false true 1329000000 1329 false false 3 false true 2097000000 2097 false false 4 false true 2657000000 2657 false false No definition available. No authoritative reference available. false 5 Other 2 pom_RevenueOther pom false credit duration monetary No definition available. false false false false false false false false false 1 false true 12000000 12 false false 2 false true -108000000 -108 false false 3 false true 21000000 21 false false 4 false true -90000000 -90 false false No definition available. No authoritative reference available. false 6 Total Operating Revenue 2 us-gaap_Revenues us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 2065000000 2065 false false 2 false true 2518000000 2518 false false 3 false true 4585000000 4585 false false 4 false true 5159000000 5159 false false No definition available. No authoritative reference available. true 10 Operating Expenses 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 13 Fuel and purchased energy 2 pom_CostElectricFuelPurchasedPower pom false debit duration monetary No definition available. false false false false false false false false false 1 false true 1491000000 1491 false false 2 false true 1832000000 1832 false false 3 false true 3378000000 3378 false false 4 false true 3650000000 3650 false false No definition available. No authoritative reference available. false 14 Other services cost of sales 2 us-gaap_OtherCostOfServices us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 82000000 82 false false 2 false true 180000000 180 false false 3 false true 178000000 178 false false 4 false true 360000000 360 false false No definition available. No authoritative reference available. false 15 Other operation and maintenance 2 pom_OtherOperationsAndMaintenanceExpenses pom false debit duration monetary No definition available. false false false false false false false false false 1 false true 237000000 237 false false 2 false true 231000000 231 false false 3 false true 473000000 473 false false 4 false true 450000000 450 false false No definition available. No authoritative reference available. false 16 Depreciation and amortization 2 us-gaap_DepreciationAndAmortization us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 95000000 95 false false 2 false true 93000000 93 false false 3 false true 191000000 191 false false 4 false true 184000000 184 false false No definition available. No authoritative reference available. false 17 Other taxes 2 us-gaap_TaxesOtherThanIncomeExciseProductionAndPropertyTaxes us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 90000000 90 false false 2 false true 85000000 85 false false 3 false true 181000000 181 false false 4 false true 173000000 173 false false No definition available. No authoritative reference available. false 18 Deferred electric service costs 2 pom_RegulatoryOperatingExpense pom false debit duration monetary No definition available. false false false false false false false false false 1 false true -57000000 -57 false false 2 false true -17000000 -17 false false 3 false true -84000000 -84 false false 4 false true 8000000 8 false false No definition available. No authoritative reference available. false 19 Effect of settlement of Mirant bankruptcy claims 2 us-gaap_GainLossRelatedToLitigationSettlement us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 0 0 false false 3 false true -14000000 -14 false false 4 false true 0 0 false false No definition available. No authoritative reference available. false 20 Gain on sale of assets 2 us-gaap_GainsLossesOnSalesOfAssets us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 0 0 false false 3 false true 0 0 false false 4 false true -3000000 -3 false false No definition available. No authoritative reference available. false 21 Total Operating Expenses 2 us-gaap_CostsAndExpenses us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 1938000000 1938 false false 2 false true 2404000000 2404 false false 3 false true 4303000000 4303 false false 4 false true 4822000000 4822 false false No definition available. No authoritative reference available. true 22 Operating Income 2 us-gaap_OperatingIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 127000000 127 false false 2 false true 114000000 114 false false 3 false true 282000000 282 false false 4 false true 337000000 337 false false No definition available. No authoritative reference available. true 23 Other Income (Expenses) 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 24 Interest and dividend income 2 us-gaap_InvestmentIncomeInterestAndDividend us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 2000000 2 false false 2 false true 5000000 5 false false 3 false true 3000000 3 false false 4 false true 12000000 12 false false No definition available. No authoritative reference available. false 25 Interest expense 2 us-gaap_InterestExpense us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -96000000 -96 false false 2 false true -80000000 -80 false false 3 false true -186000000 -186 false false 4 false true -161000000 -161 false false No definition available. No authoritative reference available. false 26 Gain (Loss) from equity investments 2 us-gaap_IncomeLossFromEquityMethodInvestments us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 2000000 2 false false 2 false true 0 0 false false 3 false true 1000000 1 false false 4 false true -2000000 -2 false false No definition available. No authoritative reference available. false 27 Other income 2 us-gaap_OtherNonoperatingIncome us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 4000000 4 false false 2 false true 4000000 4 false false 3 false true 8000000 8 false false 4 false true 10000000 10 false false No definition available. No authoritative reference available. false 28 Other expenses 2 us-gaap_OtherNonoperatingExpense us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -1000000 -1 false false 2 false true 0 0 false false 3 false true -1000000 -1 false false 4 false true -1000000 -1 false false No definition available. No authoritative reference available. false 29 Total Other Expenses 2 us-gaap_NonoperatingIncomeExpense us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -89000000 -89 false false 2 false true -71000000 -71 false false 3 false true -175000000 -175 false false 4 false true -142000000 -142 false false No definition available. No authoritative reference available. true 30 Income Before Income Tax Expense 2 pom_IncomeBeforeIncomeTaxes pom false credit duration monetary No definition available. false false false false false false false false false 1 false true 38000000 38 false false 2 false true 43000000 43 false false 3 false true 107000000 107 false false 4 false true 195000000 195 false false No definition available. No authoritative reference available. true 32 Income Tax Expense 2 us-gaap_IncomeTaxExpenseBenefit us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 13000000 13 false false 2 false true 28000000 28 false false 3 false true 37000000 37 false false 4 false true 81000000 81 false false No definition available. No authoritative reference available. false 33 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 25000000 25 false false 2 false true 15000000 15 false false 3 false true 70000000 70 false false 4 false true 114000000 114 false false No definition available. No authoritative reference available. true 34 Retained Earnings at Beginning of Period 2 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false true false false 1 false true 1257000000 1257 false false 2 false true 1238000000 1238 false false 3 false true 1271000000 1271 false false 4 false true 1193000000 1193 false false No definition available. No authoritative reference available. false 35 Dividends Paid 2 us-gaap_CashDividends us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -60000000 -60 false false 2 false true -55000000 -55 false false 3 false true -119000000 -119 false false 4 false true -109000000 -109 false false No definition available. No authoritative reference available. false 36 Retained Earnings at End of Period 2 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false false true false 1 false true 1222000000 1222 false false 2 false true 1198000000 1198 false false 3 false true 1222000000 1222 false false 4 false true 1198000000 1198 false false No definition available. No authoritative reference available. false 37 Basic and Diluted Share Information 2 pom false 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 38 Weighted average shares outstanding 2 pom_WeightedAverageNumberBasicDilutedSharesOutstanding pom false na duration shares No definition available. false false false false false false false false false 1 false true 220000000 220 false false 2 false true 201000000 201 false false 3 false true 220000000 220 false false 4 false true 201000000 201 false false No definition available. No authoritative reference available. false 39 Earnings per share of common stock 2 pom_BasicDilutedEarningsPerShareNetIncome pom false na duration decimal No definition available. false false false false false false false false true 1 true true 0.11 0.11 false false 2 true true 0.07 0.07 false false 3 true true 0.32 0.32 false false 4 true true 0.57 0.57 false false No definition available. No authoritative reference available. false 41 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 42 Operating Revenue 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 49 Operating Revenue 2 us-gaap_RegulatedOperatingRevenue us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 518000000 518 false false 2 false true 539000000 539 false false 3 false true 1095000000 1095 false false 4 false true 1064000000 1064 false false No definition available. No authoritative reference available. false 50 Operating Expenses 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 51 Purchased energy 2 us-gaap_CostOfPurchasedPower us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 273000000 273 false false 2 false true 294000000 294 false false 3 false true 622000000 622 false false 4 false true 602000000 602 false false No definition available. No authoritative reference available. false 55 Other operation and maintenance 2 pom_OtherOperationsAndMaintenanceExpenses pom false debit duration monetary No definition available. false false false false false false false false false 1 false true 81000000 81 false false 2 false true 77000000 77 false false 3 false true 160000000 160 false false 4 false true 147000000 147 false false No definition available. No authoritative reference available. false 56 Depreciation and amortization 2 us-gaap_DepreciationAndAmortization us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 37000000 37 false false 2 false true 35000000 35 false false 3 false true 72000000 72 false false 4 false true 69000000 69 false false No definition available. No authoritative reference available. false 57 Other taxes 2 us-gaap_TaxesOtherThanIncomeExciseProductionAndPropertyTaxes us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 74000000 74 false false 2 false true 69000000 69 false false 3 false true 147000000 147 false false 4 false true 139000000 139 false false No definition available. No authoritative reference available. false 59 Effect of settlement of Mirant bankruptcy claims 2 us-gaap_GainLossRelatedToLitigationSettlement us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 0 0 false false 3 false true -14000000 -14 false false 4 false true 0 0 false false No definition available. No authoritative reference available. false 61 Total Operating Expenses 2 us-gaap_CostsAndExpenses us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 465000000 465 false false 2 false true 475000000 475 false false 3 false true 987000000 987 false false 4 false true 957000000 957 false false No definition available. No authoritative reference available. true 62 Operating Income 2 us-gaap_OperatingIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 53000000 53 false false 2 false true 64000000 64 false false 3 false true 108000000 108 false false 4 false true 107000000 107 false false No definition available. No authoritative reference available. true 63 Other Income (Expenses) 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 64 Interest and dividend income 2 us-gaap_InvestmentIncomeInterestAndDividend us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 2000000 2 false false 3 false true 1000000 1 false false 4 false true 6000000 6 false false No definition available. No authoritative reference available. false 65 Interest expense 2 us-gaap_InterestExpense us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -25000000 -25 false false 2 false true -23000000 -23 false false 3 false true -50000000 -50 false false 4 false true -47000000 -47 false false No definition available. No authoritative reference available. false 67 Other income 2 us-gaap_OtherNonoperatingIncome us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 3000000 3 false false 2 false true 2000000 2 false false 3 false true 5000000 5 false false 4 false true 5000000 5 false false No definition available. No authoritative reference available. false 68 Other expenses 2 us-gaap_OtherNonoperatingExpense us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -1000000 -1 false false 2 false true 0 0 false false 3 false true -1000000 -1 false false 4 false true -1000000 -1 false false No definition available. No authoritative reference available. false 69 Total Other Expenses 2 us-gaap_NonoperatingIncomeExpense us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -23000000 -23 false false 2 false true -19000000 -19 false false 3 false true -45000000 -45 false false 4 false true -37000000 -37 false false No definition available. No authoritative reference available. true 71 Income Before Income Tax Expense 2 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 30000000 30 false false 2 false true 45000000 45 false false 3 false true 63000000 63 false false 4 false true 70000000 70 false false No definition available. No authoritative reference available. true 72 Income Tax Expense 2 us-gaap_IncomeTaxExpenseBenefit us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 13000000 13 false false 2 false true 14000000 14 false false 3 false true 27000000 27 false false 4 false true 24000000 24 false false No definition available. No authoritative reference available. false 73 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. true 74 Retained Earnings at Beginning of Period 2 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false true false false 1 false true 643000000 643 false false 2 false true 592000000 592 false false 3 false true 624000000 624 false false 4 false true 597000000 597 false false No definition available. No authoritative reference available. false 75 Dividends Paid 2 us-gaap_CashDividends us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 0 0 false false 3 false true 0 0 false false 4 false true -20000000 -20 false false No definition available. No authoritative reference available. false 76 Retained Earnings at End of Period 2 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false false true false 1 false true 660000000 660 false false 2 false true 623000000 623 false false 3 false true 660000000 660 false false 4 false true 623000000 623 false false No definition available. No authoritative reference available. false 77 Basic and Diluted Share Information 2 pom false 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 80 Operating Revenue 2 us-gaap_RegulatedOperatingRevenue us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 518000000 518 false false 2 false true 539000000 539 false false 3 false true 1095000000 1095 false false 4 false true 1064000000 1064 false false No definition available. No authoritative reference available. false 81 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 82 Operating Revenue 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 87 Electric 2 us-gaap_ElectricUtilityRevenue us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 251000000 251 false false 2 false true 289000000 289 false false 3 false true 572000000 572 false false 4 false true 584000000 584 false false No definition available. No authoritative reference available. false 88 Natural Gas 2 us-gaap_RevenueFromPurchasedOilAndGas us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 40000000 40 false false 2 false true 83000000 83 false false 3 false true 171000000 171 false false 4 false true 199000000 199 false false No definition available. No authoritative reference available. false 89 Operating Revenue 2 us-gaap_RegulatedOperatingRevenue us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 291000000 291 false false 2 false true 372000000 372 false false 3 false true 743000000 743 false false 4 false true 783000000 783 false false No definition available. No authoritative reference available. false 90 Operating Expenses 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 91 Purchased energy 2 us-gaap_CostOfPurchasedPower us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 161000000 161 false false 2 false true 192000000 192 false false 3 false true 380000000 380 false false 4 false true 387000000 387 false false No definition available. No authoritative reference available. false 92 Gas purchased 2 us-gaap_CostOfPurchasedOilAndGas us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 27000000 27 false false 2 false true 69000000 69 false false 3 false true 128000000 128 false false 4 false true 157000000 157 false false No definition available. No authoritative reference available. false 95 Other operation and maintenance 2 pom_OtherOperationsAndMaintenanceExpenses pom false debit duration monetary No definition available. false false false false false false false false false 1 false true 59000000 59 false false 2 false true 54000000 54 false false 3 false true 118000000 118 false false 4 false true 110000000 110 false false No definition available. No authoritative reference available. false 96 Depreciation and amortization 2 us-gaap_DepreciationAndAmortization us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 18000000 18 false false 2 false true 18000000 18 false false 3 false true 37000000 37 false false 4 false true 36000000 36 false false No definition available. No authoritative reference available. false 97 Other taxes 2 us-gaap_TaxesOtherThanIncomeExciseProductionAndPropertyTaxes us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 9000000 9 false false 2 false true 8000000 8 false false 3 false true 19000000 19 false false 4 false true 18000000 18 false false No definition available. No authoritative reference available. false 100 Gain on sale of assets 2 us-gaap_GainsLossesOnSalesOfAssets us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 0 0 false false 3 false true 0 0 false false 4 false true -3000000 -3 false false No definition available. No authoritative reference available. false 101 Total Operating Expenses 2 us-gaap_CostsAndExpenses us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 274000000 274 false false 2 false true 341000000 341 false false 3 false true 682000000 682 false false 4 false true 705000000 705 false false No definition available. No authoritative reference available. true 102 Operating Income 2 us-gaap_OperatingIncomeLoss 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 61000000 61 false false 4 false true 78000000 78 false false No definition available. No authoritative reference available. true 103 Other Income (Expenses) 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 104 Interest and dividend income 2 us-gaap_InvestmentIncomeInterestAndDividend us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 1000000 1 false false 3 false true 0 0 false false 4 false true 2000000 2 false false No definition available. No authoritative reference available. false 105 Interest expense 2 us-gaap_InterestExpense us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -11000000 -11 false false 2 false true -9000000 -9 false false 3 false true -22000000 -22 false false 4 false true -19000000 -19 false false No definition available. No authoritative reference available. false 107 Other income 2 us-gaap_OtherNonoperatingIncome us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 1000000 1 false false 2 false true 1000000 1 false false 3 false true 1000000 1 false false 4 false true 2000000 2 false false No definition available. No authoritative reference available. false 109 Total Other Expenses 2 us-gaap_NonoperatingIncomeExpense 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 -7000000 -7 false false 3 false true -21000000 -21 false false 4 false true -15000000 -15 false false No definition available. No authoritative reference available. true 111 Income Before Income Tax Expense 2 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 7000000 7 false false 2 false true 24000000 24 false false 3 false true 40000000 40 false false 4 false true 63000000 63 false false No definition available. No authoritative reference available. true 112 Income Tax Expense 2 us-gaap_IncomeTaxExpenseBenefit 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 8000000 8 false false 3 false true 14000000 14 false false 4 false true 21000000 21 false false No definition available. No authoritative reference available. false 113 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. true 114 Retained Earnings at Beginning of Period 2 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false true false false 1 false true 441000000 441 false false 2 false true 431000000 431 false false 3 false true 448000000 448 false false 4 false true 432000000 432 false false No definition available. No authoritative reference available. false 115 Dividends Paid 2 us-gaap_CashDividends us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true -15000000 -15 false false 3 false true -28000000 -28 false false 4 false true -42000000 -42 false false No definition available. No authoritative reference available. false 116 Retained Earnings at End of Period 2 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false false true false 1 false true 446000000 446 false false 2 false true 432000000 432 false false 3 false true 446000000 446 false false 4 false true 432000000 432 false false No definition available. No authoritative reference available. false 117 Basic and Diluted Share Information 2 pom false 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 120 Operating Revenue 2 us-gaap_RegulatedOperatingRevenue us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 291000000 291 false false 2 false true 372000000 372 false false 3 false true 743000000 743 false false 4 false true 783000000 783 false false No definition available. No authoritative reference available. false 121 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 122 Operating Revenue 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 129 Operating Revenue 2 us-gaap_RegulatedOperatingRevenue us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 287000000 287 false false 2 false true 387000000 387 false false 3 false true 631000000 631 false false 4 false true 748000000 748 false false No definition available. No authoritative reference available. false 130 Operating Expenses 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 131 Purchased energy 2 us-gaap_CostOfPurchasedPower us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 239000000 239 false false 2 false true 273000000 273 false false 3 false true 516000000 516 false false 4 false true 518000000 518 false false No definition available. No authoritative reference available. false 135 Other operation and maintenance 2 pom_OtherOperationsAndMaintenanceExpenses pom false debit duration monetary No definition available. false false false false false false false false false 1 false true 47000000 47 false false 2 false true 43000000 43 false false 3 false true 95000000 95 false false 4 false true 89000000 89 false false No definition available. No authoritative reference available. false 136 Depreciation and amortization 2 us-gaap_DepreciationAndAmortization us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 24000000 24 false false 2 false true 25000000 25 false false 3 false true 49000000 49 false false 4 false true 49000000 49 false false No definition available. No authoritative reference available. false 137 Other taxes 2 us-gaap_TaxesOtherThanIncomeExciseProductionAndPropertyTaxes us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 5000000 5 false false 2 false true 6000000 6 false false 3 false true 10000000 10 false false 4 false true 12000000 12 false false No definition available. No authoritative reference available. false 138 Deferred electric service costs 2 pom_RegulatoryOperatingExpense pom false debit duration monetary No definition available. false false false false false false false false false 1 false true -57000000 -57 false false 2 false true -17000000 -17 false false 3 false true -84000000 -84 false false 4 false true 8000000 8 false false No definition available. No authoritative reference available. false 141 Total Operating Expenses 2 us-gaap_CostsAndExpenses us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 258000000 258 false false 2 false true 330000000 330 false false 3 false true 586000000 586 false false 4 false true 676000000 676 false false No definition available. No authoritative reference available. true 142 Operating Income 2 us-gaap_OperatingIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 29000000 29 false false 2 false true 57000000 57 false false 3 false true 45000000 45 false false 4 false true 72000000 72 false false No definition available. No authoritative reference available. true 143 Other Income (Expenses) 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 144 Interest and dividend income 2 us-gaap_InvestmentIncomeInterestAndDividend us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 0 0 false false 3 false true 0 0 false false 4 false true 1000000 1 false false No definition available. No authoritative reference available. false 145 Interest expense 2 us-gaap_InterestExpense us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -17000000 -17 false false 2 false true -15000000 -15 false false 3 false true -34000000 -34 false false 4 false true -30000000 -30 false false No definition available. No authoritative reference available. false 147 Other income 2 us-gaap_OtherNonoperatingIncome us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 1000000 1 false false 3 false true 1000000 1 false false 4 false true 2000000 2 false false No definition available. No authoritative reference available. false 149 Total Other Expenses 2 us-gaap_NonoperatingIncomeExpense 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 -14000000 -14 false false 3 false true -33000000 -33 false false 4 false true -27000000 -27 false false No definition available. No authoritative reference available. true 151 Income Before Income Tax Expense 2 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 12000000 12 false false 2 false true 43000000 43 false false 3 false true 12000000 12 false false 4 false true 45000000 45 false false No definition available. No authoritative reference available. true 152 Income Tax Expense 2 us-gaap_IncomeTaxExpenseBenefit us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 4000000 4 false false 2 false true 16000000 16 false false 3 false true 2000000 2 false false 4 false true 13000000 13 false false No definition available. No authoritative reference available. false 153 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 8000000 8 false false 2 false true 27000000 27 false false 3 false true 10000000 10 false false 4 false true 32000000 32 false false No definition available. No authoritative reference available. true 154 Retained Earnings at Beginning of Period 2 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false true false false 1 false true 144000000 144 false false 2 false true 147000000 147 false false 3 false true 166000000 166 false false 4 false true 142000000 142 false false No definition available. No authoritative reference available. false 155 Dividends Paid 2 us-gaap_CashDividends us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true -31000000 -31 false false 3 false true -24000000 -24 false false 4 false true -31000000 -31 false false No definition available. No authoritative reference available. false 156 Retained Earnings at End of Period 2 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false false true false 1 false true 152000000 152 false false 2 false true 143000000 143 false false 3 false true 152000000 152 false false 4 false true 143000000 143 false false No definition available. No authoritative reference available. false 157 Basic and Diluted Share Information 2 pom false 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 160 Operating Revenue 2 us-gaap_RegulatedOperatingRevenue us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 287000000 287 false false 2 true true 387000000 387 false false 3 true true 631000000 631 false false 4 true true 748000000 748 false false No definition available. No authoritative reference available. false false 4 109 false Millions Millions Hundreds false true