1.0.0.3 true Statement Of Financial Position Classified (USD $) In Millions 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 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 No definition available. No authoritative reference available. false 2 CURRENT ASSETS 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 No definition available. false 3 Cash and cash equivalents 2 us-gaap_CashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 true true 20000000 20 false false 2 true true 384000000 384 false false No definition available. No authoritative reference available. false 4 Restricted cash equivalents 2 us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 11000000 11 false false 2 false true 10000000 10 false false No definition available. No authoritative reference available. false 5 Accounts receivable, less allowance for uncollectible accounts 2 us-gaap_AccountsReceivableNetCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 1184000000 1184 false false 2 false true 1392000000 1392 false false No definition available. No authoritative reference available. false 6 Inventories 2 us-gaap_InventoryNet us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 286000000 286 false false 2 false true 333000000 333 false false No definition available. No authoritative reference available. false 7 Derivative assets 2 us-gaap_DerivativeAssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 62000000 62 false false 2 false true 98000000 98 false false No definition available. No authoritative reference available. false 8 Prepayments of income taxes 2 us-gaap_PrepaidTaxes us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 365000000 365 false false 2 false true 294000000 294 false false No definition available. No authoritative reference available. false 9 Prepaid expenses and other 2 us-gaap_OtherAssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 111000000 111 false false 2 false true 87000000 87 false false No definition available. No authoritative reference available. false 10 Total Current Assets 2 us-gaap_AssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 2039000000 2039 false false 2 false true 2598000000 2598 false false No definition available. No authoritative reference available. true 11 INVESTMENTS AND OTHER ASSETS 2 pom false na duration string Investments and Other Assets [Abstract] false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false Investments and Other Assets [Abstract] false 12 Goodwill 2 us-gaap_Goodwill us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 1411000000 1411 false false 2 false true 1411000000 1411 false false No definition available. No authoritative reference available. false 13 Regulatory assets 2 us-gaap_RegulatoryAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 1951000000 1951 false false 2 false true 2088000000 2088 false false No definition available. No authoritative reference available. false 14 Investment in finance leases held in trust 2 us-gaap_AssetsHeldInTrustNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 1376000000 1376 false false 2 false true 1335000000 1335 false false No definition available. No authoritative reference available. false 15 Income taxes receivable 2 us-gaap_IncomeTaxesReceivableNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 128000000 128 false false 2 false true 23000000 23 false false No definition available. No authoritative reference available. false 16 Restricted cash equivalents 2 us-gaap_RestrictedCashAndCashEquivalentsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 4000000 4 false false 2 false true 108000000 108 false false No definition available. No authoritative reference available. false 17 Assets and accrued interest related to uncertain tax positions 2 pom_AssetsAndAccruedInterestRelatedToUncertainTaxPositionsNoncurrent pom false debit instant monetary The noncurrent portion of the assets recognized for uncertain tax positions as of the balance sheet date, including interest... false false false false false false false false false 1 false true 12000000 12 false false 2 false true 32000000 32 false false The noncurrent portion of the assets recognized for uncertain tax positions as of the balance sheet date, including interest and penalties. No authoritative reference available. false 18 Derivative assets 2 us-gaap_DerivativeAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 27000000 27 false false 2 false true 9000000 9 false false No definition available. No authoritative reference available. false 21 Other 2 us-gaap_OtherAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 208000000 208 false false 2 false true 215000000 215 false false No definition available. No authoritative reference available. false 22 Total Investments and Other Assets 2 pom_InvestmentsAndOtherAssets pom false debit instant monetary Total investments and other assets false false false false false false false false false 1 false true 5117000000 5117 false false 2 false true 5221000000 5221 false false Total investments and other assets No authoritative reference available. true 23 PROPERTY, PLANT AND EQUIPMENT 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 No definition available. false 24 Property, plant and equipment 2 us-gaap_PropertyPlantAndEquipmentGross us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 13476000000 13476 false false 2 false true 12926000000 12926 false false No definition available. No authoritative reference available. false 25 Accumulated depreciation 2 us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true -4802000000 -4802 false false 2 false true -4612000000 -4612 false false No definition available. No authoritative reference available. false 26 Net Property, Plant and Equipment 2 us-gaap_PropertyPlantAndEquipmentNet us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 8674000000 8674 false false 2 false true 8314000000 8314 false false No definition available. No authoritative reference available. true 27 TOTAL ASSETS 2 us-gaap_Assets us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 15830000000 15830 false false 2 false true 16133000000 16133 false false No definition available. No authoritative reference available. true 28 CURRENT LIABILITIES 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 No definition available. false 29 Short-term debt 2 us-gaap_ShortTermBorrowings us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 493000000 493 false false 2 false true 465000000 465 false false No definition available. No authoritative reference available. false 30 Current maturities of long-term debt 2 us-gaap_LongTermDebtCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 534000000 534 false false 2 false true 85000000 85 false false No definition available. No authoritative reference available. false 31 Accounts payable and accrued liabilities 2 us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 634000000 634 false false 2 false true 847000000 847 false false No definition available. No authoritative reference available. false 33 Capital lease obligations due within one year 2 us-gaap_CapitalLeaseObligationsCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 7000000 7 false false 2 false true 6000000 6 false false No definition available. No authoritative reference available. false 34 Taxes accrued 2 us-gaap_TaxesPayableCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 58000000 58 false false 2 false true 62000000 62 false false No definition available. No authoritative reference available. false 35 Interest accrued 2 us-gaap_InterestPayableCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 93000000 93 false false 2 false true 71000000 71 false false No definition available. No authoritative reference available. false 36 Liabilities and accrued interest related to uncertain tax positions 2 us-gaap_LiabilityForUncertainTaxPositionsCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 1000000 1 false false 2 false true 47000000 47 false false No definition available. No authoritative reference available. false 37 Derivative liabilities 2 us-gaap_DerivativeLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 125000000 125 false false 2 false true 144000000 144 false false No definition available. No authoritative reference available. false 38 Other 2 us-gaap_OtherLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 289000000 289 false false 2 false true 275000000 275 false false No definition available. No authoritative reference available. false 39 Total Current Liabilities 2 us-gaap_LiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 2234000000 2234 false false 2 false true 2002000000 2002 false false No definition available. No authoritative reference available. true 40 DEFERRED CREDITS 2 pom false na duration string Deferred Credits and Regulatory Liabilities [Abstract] false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false Deferred Credits and Regulatory Liabilities [Abstract] false 41 Regulatory liabilities 2 us-gaap_RegulatoryLiabilityNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 662000000 662 false false 2 false true 893000000 893 false false No definition available. No authoritative reference available. false 42 Deferred income taxes, net 2 us-gaap_DeferredTaxLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 2505000000 2505 false false 2 false true 2269000000 2269 false false No definition available. No authoritative reference available. false 43 Investment tax credits 2 us-gaap_AccumulatedDeferredInvestmentTaxCredit us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 37000000 37 false false 2 false true 40000000 40 false false No definition available. No authoritative reference available. false 45 Pension benefit obligation 2 us-gaap_DefinedBenefitPensionPlanLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 399000000 399 false false 2 false true 626000000 626 false false No definition available. No authoritative reference available. false 46 Other postretirement benefit obligation 2 us-gaap_OtherPostretirementDefinedBenefitPlanLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 451000000 451 false false 2 false true 461000000 461 false false No definition available. No authoritative reference available. false 47 Income taxes payable 2 us-gaap_AccruedIncomeTaxesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 1000000 1 false false 2 false true 8000000 8 false false No definition available. No authoritative reference available. false 48 Liabilities and accrued interest related to uncertain tax positions 2 us-gaap_LiabilityForUncertainTaxPositionsNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 110000000 110 false false 2 false true 17000000 17 false false No definition available. No authoritative reference available. false 49 Derivative liabilities 2 us-gaap_DerivativeLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 63000000 63 false false 2 false true 59000000 59 false false No definition available. No authoritative reference available. false 50 Other 2 us-gaap_OtherLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 155000000 155 false false 2 false true 184000000 184 false false No definition available. No authoritative reference available. false 51 Total Deferred Credits 2 pom_TotalDeferredCreditsAndOtherLiabilities pom false credit instant monetary Total deferred credits and other liabilities. false false false false false false false false false 1 false true 4383000000 4383 false false 2 false true 4557000000 4557 false false Total deferred credits and other liabilities. No authoritative reference available. true 52 LONG-TERM LIABILITIES 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 No definition available. false 53 Long-term debt 2 us-gaap_LongTermDebtNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 4470000000 4470 false false 2 false true 4859000000 4859 false false No definition available. No authoritative reference available. false 54 Transition bonds issued by ACE Funding 2 us-gaap_LongTermTransitionBond us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 378000000 378 false false 2 false true 401000000 401 false false No definition available. No authoritative reference available. false 55 Long-term project funding 2 us-gaap_OtherLongTermDebtNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 17000000 17 false false 2 false true 19000000 19 false false No definition available. No authoritative reference available. false 56 Capital lease obligations 2 us-gaap_CapitalLeaseObligationsNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 96000000 96 false false 2 false true 99000000 99 false false No definition available. No authoritative reference available. false 57 Total Long-Term Liabilities 2 us-gaap_LongTermDebtAndCapitalLeaseObligations us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 4961000000 4961 false false 2 false true 5378000000 5378 false false No definition available. No authoritative reference available. true 59 COMMITMENTS AND CONTINGENCIES 2 us-gaap_CommitmentsAndContingencies2009 us-gaap true na duration string No definition available. false false false false false false false false false 1 false false 0 0 - false false 2 false false 0 0 - false false No definition available. No authoritative reference available. false 61 EQUITY 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 No definition available. false 62 Common stock 2 us-gaap_CommonStockValue us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 2000000 2 false false 2 false true 2000000 2 false false No definition available. No authoritative reference available. false 63 Premium on stock and other capital contributions 2 us-gaap_AdditionalPaidInCapitalCommonStock us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 3215000000 3215 false false 2 false true 3179000000 3179 false false No definition available. No authoritative reference available. false 64 Accumulated other comprehensive loss 2 us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true -258000000 -258 false false 2 false true -262000000 -262 false false No definition available. No authoritative reference available. false 65 Retained earnings 2 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 1287000000 1287 false false 2 false true 1271000000 1271 false false No definition available. No authoritative reference available. false 66 Total Equity 2 us-gaap_StockholdersEquity us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 4246000000 4246 false false 2 false true 4190000000 4190 false false No definition available. No authoritative reference available. true 67 Noncontrolling interest 2 us-gaap_MinorityInterest us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 6000000 6 false false 2 false true 6000000 6 false false No definition available. No authoritative reference available. false 68 Total Equity 2 us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 4252000000 4252 false false 2 false true 4196000000 4196 false false No definition available. No authoritative reference available. true 69 TOTAL LIABILITIES AND EQUITY 2 us-gaap_LiabilitiesAndStockholdersEquity us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 15830000000 15830 false false 2 false true 16133000000 16133 false false No definition available. No authoritative reference available. true 70 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 No definition available. No authoritative reference available. false 71 CURRENT ASSETS 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 No definition available. false 72 Cash and cash equivalents 2 us-gaap_CashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 154000000 154 false false 2 false true 146000000 146 false false No definition available. No authoritative reference available. false 74 Accounts receivable, less allowance for uncollectible accounts 2 us-gaap_AccountsReceivableNetCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 389000000 389 false false 2 false true 377000000 377 false false No definition available. No authoritative reference available. false 75 Inventories 2 us-gaap_InventoryNet us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 47000000 47 false false 2 false true 45000000 45 false false No definition available. No authoritative reference available. false 77 Prepayments of income taxes 2 us-gaap_PrepaidTaxes us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 120000000 120 false false 2 false true 151000000 151 false false No definition available. No authoritative reference available. false 78 Prepaid expenses and other 2 us-gaap_OtherAssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 23000000 23 false false 2 false true 23000000 23 false false No definition available. No authoritative reference available. false 79 Total Current Assets 2 us-gaap_AssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 733000000 733 false false 2 false true 742000000 742 false false No definition available. No authoritative reference available. true 80 INVESTMENTS AND OTHER ASSETS 2 pom false na duration string Investments and Other Assets [Abstract] false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false Investments and Other Assets [Abstract] false 82 Regulatory assets 2 us-gaap_RegulatoryAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 163000000 163 false false 2 false true 169000000 169 false false No definition available. No authoritative reference available. false 84 Income taxes receivable 2 us-gaap_IncomeTaxesReceivableNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 60000000 60 false false 2 false true 36000000 36 false false No definition available. No authoritative reference available. false 85 Restricted cash equivalents 2 us-gaap_RestrictedCashAndCashEquivalentsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 102000000 102 false false No definition available. No authoritative reference available. false 86 Assets and accrued interest related to uncertain tax positions 2 pom_AssetsAndAccruedInterestRelatedToUncertainTaxPositionsNoncurrent pom false debit instant monetary The noncurrent portion of the assets recognized for uncertain tax positions as of the balance sheet date, including interest... false false false false false false false false false 1 false true 0 0 false false 2 false true 29000000 29 false false The noncurrent portion of the assets recognized for uncertain tax positions as of the balance sheet date, including interest and penalties. No authoritative reference available. false 88 Prepaid pension expense 2 us-gaap_PrepaidPensionCosts us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 295000000 295 false false 2 false true 142000000 142 false false No definition available. No authoritative reference available. false 89 Investment in trust 2 us-gaap_DeferredCompensationPlanAssets us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 26000000 26 false false 2 false true 24000000 24 false false No definition available. No authoritative reference available. false 90 Other 2 us-gaap_OtherAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 75000000 75 false false 2 false true 70000000 70 false false No definition available. No authoritative reference available. false 91 Total Investments and Other Assets 2 pom_InvestmentsAndOtherAssets pom false debit instant monetary Total investments and other assets false false false false false false false false false 1 false true 619000000 619 false false 2 false true 572000000 572 false false Total investments and other assets No authoritative reference available. true 92 PROPERTY, PLANT AND EQUIPMENT 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 No definition available. false 93 Property, plant and equipment 2 us-gaap_PropertyPlantAndEquipmentGross us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 5780000000 5780 false false 2 false true 5607000000 5607 false false No definition available. No authoritative reference available. false 94 Accumulated depreciation 2 us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true -2454000000 -2454 false false 2 false true -2371000000 -2371 false false No definition available. No authoritative reference available. false 95 Net Property, Plant and Equipment 2 us-gaap_PropertyPlantAndEquipmentNet us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 3326000000 3326 false false 2 false true 3236000000 3236 false false No definition available. No authoritative reference available. true 96 TOTAL ASSETS 2 us-gaap_Assets us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 4678000000 4678 false false 2 false true 4550000000 4550 false false No definition available. No authoritative reference available. true 97 CURRENT LIABILITIES 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 No definition available. false 98 Short-term debt 2 us-gaap_ShortTermBorrowings us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 125000000 125 false false No definition available. No authoritative reference available. false 99 Current maturities of long-term debt 2 us-gaap_LongTermDebtCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 16000000 16 false false 2 false true 50000000 50 false false No definition available. No authoritative reference available. false 100 Accounts payable and accrued liabilities 2 us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 152000000 152 false false 2 false true 187000000 187 false false No definition available. No authoritative reference available. false 101 Accounts payable due to associated companies 2 us-gaap_AccountsPayableRelatedPartiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 71000000 71 false false 2 false true 70000000 70 false false No definition available. No authoritative reference available. false 102 Capital lease obligations due within one year 2 us-gaap_CapitalLeaseObligationsCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 7000000 7 false false 2 false true 6000000 6 false false No definition available. No authoritative reference available. false 103 Taxes accrued 2 us-gaap_TaxesPayableCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 45000000 45 false false 2 false true 44000000 44 false false No definition available. No authoritative reference available. false 104 Interest accrued 2 us-gaap_InterestPayableCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 37000000 37 false false 2 false true 19000000 19 false false No definition available. No authoritative reference available. false 105 Liabilities and accrued interest related to uncertain tax positions 2 us-gaap_LiabilityForUncertainTaxPositionsCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 24000000 24 false false No definition available. No authoritative reference available. false 107 Other 2 us-gaap_OtherLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 127000000 127 false false 2 false true 94000000 94 false false No definition available. No authoritative reference available. false 108 Total Current Liabilities 2 us-gaap_LiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 455000000 455 false false 2 false true 619000000 619 false false No definition available. No authoritative reference available. true 109 DEFERRED CREDITS 2 pom false na duration string Deferred Credits and Regulatory Liabilities [Abstract] false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false Deferred Credits and Regulatory Liabilities [Abstract] false 110 Regulatory liabilities 2 us-gaap_RegulatoryLiabilityNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 145000000 145 false false 2 false true 239000000 239 false false No definition available. No authoritative reference available. false 111 Deferred income taxes, net 2 us-gaap_DeferredTaxLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 876000000 876 false false 2 false true 788000000 788 false false No definition available. No authoritative reference available. false 112 Investment tax credits 2 us-gaap_AccumulatedDeferredInvestmentTaxCredit us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 9000000 9 false false 2 false true 10000000 10 false false No definition available. No authoritative reference available. false 115 Other postretirement benefit obligation 2 us-gaap_OtherPostretirementDefinedBenefitPlanLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 50000000 50 false false 2 false true 49000000 49 false false No definition available. No authoritative reference available. false 116 Income taxes payable 2 us-gaap_AccruedIncomeTaxesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 7000000 7 false false No definition available. No authoritative reference available. false 119 Other 2 us-gaap_OtherLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 85000000 85 false false 2 false true 59000000 59 false false No definition available. No authoritative reference available. false 120 Total Deferred Credits 2 pom_TotalDeferredCreditsAndOtherLiabilities pom false credit instant monetary Total deferred credits and other liabilities. false false false false false false false false false 1 false true 1165000000 1165 false false 2 false true 1152000000 1152 false false Total deferred credits and other liabilities. No authoritative reference available. true 121 LONG-TERM LIABILITIES 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 No definition available. false 122 Long-term debt 2 us-gaap_LongTermDebtNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 1538000000 1538 false false 2 false true 1445000000 1445 false false No definition available. No authoritative reference available. false 125 Capital lease obligations 2 us-gaap_CapitalLeaseObligationsNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 96000000 96 false false 2 false true 99000000 99 false false No definition available. No authoritative reference available. false 126 Total Long-Term Liabilities 2 us-gaap_LongTermDebtAndCapitalLeaseObligations us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 1634000000 1634 false false 2 false true 1544000000 1544 false false No definition available. No authoritative reference available. true 128 COMMITMENTS AND CONTINGENCIES 2 us-gaap_CommitmentsAndContingencies2009 us-gaap true na duration string No definition available. false false false false false false false false false 1 false false 0 0 - false false 2 false false 0 0 - false false No definition available. No authoritative reference available. false 130 EQUITY 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 No definition available. false 131 Common stock 2 us-gaap_CommonStockValue us-gaap true credit instant 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 No definition available. No authoritative reference available. false 132 Premium on stock and other capital contributions 2 us-gaap_AdditionalPaidInCapitalCommonStock us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 706000000 706 false false 2 false true 611000000 611 false false No definition available. No authoritative reference available. false 134 Retained earnings 2 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 718000000 718 false false 2 false true 624000000 624 false false No definition available. No authoritative reference available. false 135 Total Equity 2 us-gaap_StockholdersEquity us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 1424000000 1424 false false 2 false true 1235000000 1235 false false No definition available. No authoritative reference available. true 138 TOTAL LIABILITIES AND EQUITY 2 us-gaap_LiabilitiesAndStockholdersEquity us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 4678000000 4678 false false 2 false true 4550000000 4550 false false No definition available. No authoritative reference available. true 139 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 No definition available. No authoritative reference available. false 140 CURRENT ASSETS 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 No definition available. false 141 Cash and cash equivalents 2 us-gaap_CashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 6000000 6 false false 2 false true 138000000 138 false false No definition available. No authoritative reference available. false 143 Accounts receivable, less allowance for uncollectible accounts 2 us-gaap_AccountsReceivableNetCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 172000000 172 false false 2 false true 202000000 202 false false No definition available. No authoritative reference available. false 144 Inventories 2 us-gaap_InventoryNet us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 46000000 46 false false 2 false true 52000000 52 false false No definition available. No authoritative reference available. false 146 Prepayments of income taxes 2 us-gaap_PrepaidTaxes us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 91000000 91 false false 2 false true 34000000 34 false false No definition available. No authoritative reference available. false 147 Prepaid expenses and other 2 us-gaap_OtherAssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 20000000 20 false false 2 false true 18000000 18 false false No definition available. No authoritative reference available. false 148 Total Current Assets 2 us-gaap_AssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 335000000 335 false false 2 false true 444000000 444 false false No definition available. No authoritative reference available. true 149 INVESTMENTS AND OTHER ASSETS 2 pom false na duration string Investments and Other Assets [Abstract] false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false Investments and Other Assets [Abstract] false 150 Goodwill 2 us-gaap_Goodwill us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 8000000 8 false false 2 false true 8000000 8 false false No definition available. No authoritative reference available. false 151 Regulatory assets 2 us-gaap_RegulatoryAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 200000000 200 false false 2 false true 244000000 244 false false No definition available. No authoritative reference available. false 157 Prepaid pension expense 2 us-gaap_PrepaidPensionCosts us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 184000000 184 false false 2 false true 184000000 184 false false No definition available. No authoritative reference available. false 159 Other 2 us-gaap_OtherAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 29000000 29 false false 2 false true 21000000 21 false false No definition available. No authoritative reference available. false 160 Total Investments and Other Assets 2 pom_InvestmentsAndOtherAssets pom false debit instant monetary Total investments and other assets false false false false false false false false false 1 false true 421000000 421 false false 2 false true 457000000 457 false false Total investments and other assets No authoritative reference available. true 161 PROPERTY, PLANT AND EQUIPMENT 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 No definition available. false 162 Property, plant and equipment 2 us-gaap_PropertyPlantAndEquipmentGross us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 2760000000 2760 false false 2 false true 2656000000 2656 false false No definition available. No authoritative reference available. false 163 Accumulated depreciation 2 us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true -857000000 -857 false false 2 false true -827000000 -827 false false No definition available. No authoritative reference available. false 164 Net Property, Plant and Equipment 2 us-gaap_PropertyPlantAndEquipmentNet us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 1903000000 1903 false false 2 false true 1829000000 1829 false false No definition available. No authoritative reference available. true 165 TOTAL ASSETS 2 us-gaap_Assets us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 2659000000 2659 false false 2 false true 2730000000 2730 false false No definition available. No authoritative reference available. true 166 CURRENT LIABILITIES 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 No definition available. false 167 Short-term debt 2 us-gaap_ShortTermBorrowings us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 105000000 105 false false 2 false true 246000000 246 false false No definition available. No authoritative reference available. false 168 Current maturities of long-term debt 2 us-gaap_LongTermDebtCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 31000000 31 false false 2 false true 0 0 false false No definition available. No authoritative reference available. false 169 Accounts payable and accrued liabilities 2 us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 66000000 66 false false 2 false true 108000000 108 false false No definition available. No authoritative reference available. false 170 Accounts payable due to associated companies 2 us-gaap_AccountsPayableRelatedPartiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 23000000 23 false false 2 false true 34000000 34 false false No definition available. No authoritative reference available. false 172 Taxes accrued 2 us-gaap_TaxesPayableCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 7000000 7 false false 2 false true 7000000 7 false false No definition available. No authoritative reference available. false 173 Interest accrued 2 us-gaap_InterestPayableCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 13000000 13 false false 2 false true 6000000 6 false false No definition available. No authoritative reference available. false 174 Liabilities and accrued interest related to uncertain tax positions 2 us-gaap_LiabilityForUncertainTaxPositionsCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 13000000 13 false false No definition available. No authoritative reference available. false 175 Derivative liabilities 2 us-gaap_DerivativeLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 13000000 13 false false 2 false true 13000000 13 false false No definition available. No authoritative reference available. false 176 Other 2 us-gaap_OtherLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 69000000 69 false false 2 false true 56000000 56 false false No definition available. No authoritative reference available. false 177 Total Current Liabilities 2 us-gaap_LiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 327000000 327 false false 2 false true 483000000 483 false false No definition available. No authoritative reference available. true 178 DEFERRED CREDITS 2 pom false na duration string Deferred Credits and Regulatory Liabilities [Abstract] false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false Deferred Credits and Regulatory Liabilities [Abstract] false 179 Regulatory liabilities 2 us-gaap_RegulatoryLiabilityNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 293000000 293 false false 2 false true 277000000 277 false false No definition available. No authoritative reference available. false 180 Deferred income taxes, net 2 us-gaap_DeferredTaxLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 492000000 492 false false 2 false true 446000000 446 false false No definition available. No authoritative reference available. false 181 Investment tax credits 2 us-gaap_AccumulatedDeferredInvestmentTaxCredit us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 8000000 8 false false 2 false true 8000000 8 false false No definition available. No authoritative reference available. false 182 Above-market purchased energy contracts and other electric restructuring liabilities 2 us-gaap_RestructuringReserveNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 17000000 17 false false 2 false true 19000000 19 false false No definition available. No authoritative reference available. false 187 Derivative liabilities 2 us-gaap_DerivativeLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 14000000 14 false false 2 false true 14000000 14 false false No definition available. No authoritative reference available. false 188 Other 2 us-gaap_OtherLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 57000000 57 false false 2 false true 45000000 45 false false No definition available. No authoritative reference available. false 189 Total Deferred Credits 2 pom_TotalDeferredCreditsAndOtherLiabilities pom false credit instant monetary Total deferred credits and other liabilities. false false false false false false false false false 1 false true 881000000 881 false false 2 false true 809000000 809 false false Total deferred credits and other liabilities. No authoritative reference available. true 190 LONG-TERM LIABILITIES 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 No definition available. false 191 Long-term debt 2 us-gaap_LongTermDebtNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 655000000 655 false false 2 false true 686000000 686 false false No definition available. No authoritative reference available. false 197 COMMITMENTS AND CONTINGENCIES 2 us-gaap_CommitmentsAndContingencies2009 us-gaap true na duration string No definition available. false false false false false false false false false 1 false false 0 0 - false false 2 false false 0 0 - false false No definition available. No authoritative reference available. false 199 EQUITY 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 No definition available. false 200 Common stock 2 us-gaap_CommonStockValue us-gaap true credit instant 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 No definition available. No authoritative reference available. false 201 Premium on stock and other capital contributions 2 us-gaap_AdditionalPaidInCapitalCommonStock us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 336000000 336 false false 2 false true 304000000 304 false false No definition available. No authoritative reference available. false 203 Retained earnings 2 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 460000000 460 false false 2 false true 448000000 448 false false No definition available. No authoritative reference available. false 204 Total Equity 2 us-gaap_StockholdersEquity us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 796000000 796 false false 2 false true 752000000 752 false false No definition available. No authoritative reference available. true 207 TOTAL LIABILITIES AND EQUITY 2 us-gaap_LiabilitiesAndStockholdersEquity us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 2659000000 2659 false false 2 false true 2730000000 2730 false false No definition available. No authoritative reference available. true 208 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 No definition available. No authoritative reference available. false 209 CURRENT ASSETS 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 No definition available. false 210 Cash and cash equivalents 2 us-gaap_CashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 5000000 5 false false 2 false true 65000000 65 false false No definition available. No authoritative reference available. false 211 Restricted cash equivalents 2 us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 11000000 11 false false 2 false true 10000000 10 false false No definition available. No authoritative reference available. false 212 Accounts receivable, less allowance for uncollectible accounts 2 us-gaap_AccountsReceivableNetCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 200000000 200 false false 2 false true 195000000 195 false false No definition available. No authoritative reference available. false 213 Inventories 2 us-gaap_InventoryNet us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 16000000 16 false false 2 false true 15000000 15 false false No definition available. No authoritative reference available. false 215 Prepayments of income taxes 2 us-gaap_PrepaidTaxes us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 52000000 52 false false 2 false true 47000000 47 false false No definition available. No authoritative reference available. false 216 Prepaid expenses and other 2 us-gaap_OtherAssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 40000000 40 false false 2 false true 16000000 16 false false No definition available. No authoritative reference available. false 217 Total Current Assets 2 us-gaap_AssetsCurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 324000000 324 false false 2 false true 348000000 348 false false No definition available. No authoritative reference available. true 218 INVESTMENTS AND OTHER ASSETS 2 pom false na duration string Investments and Other Assets [Abstract] false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false Investments and Other Assets [Abstract] false 220 Regulatory assets 2 us-gaap_RegulatoryAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 721000000 721 false false 2 false true 768000000 768 false false No definition available. No authoritative reference available. false 222 Income taxes receivable 2 us-gaap_IncomeTaxesReceivableNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 71000000 71 false false 2 false true 10000000 10 false false No definition available. No authoritative reference available. false 223 Restricted cash equivalents 2 us-gaap_RestrictedCashAndCashEquivalentsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 4000000 4 false false 2 false true 5000000 5 false false No definition available. No authoritative reference available. false 224 Assets and accrued interest related to uncertain tax positions 2 pom_AssetsAndAccruedInterestRelatedToUncertainTaxPositionsNoncurrent pom false debit instant monetary The noncurrent portion of the assets recognized for uncertain tax positions as of the balance sheet date, including interest... false false false false false false false false false 1 false true 54000000 54 false false 2 false true 110000000 110 false false The noncurrent portion of the assets recognized for uncertain tax positions as of the balance sheet date, including interest and penalties. No authoritative reference available. false 226 Prepaid pension expense 2 us-gaap_PrepaidPensionCosts us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 59000000 59 false false 2 false true 6000000 6 false false No definition available. No authoritative reference available. false 228 Other 2 us-gaap_OtherAssetsNoncurrent us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 10000000 10 false false 2 false true 12000000 12 false false No definition available. No authoritative reference available. false 229 Total Investments and Other Assets 2 pom_InvestmentsAndOtherAssets pom false debit instant monetary Total investments and other assets false false false false false false false false false 1 false true 919000000 919 false false 2 false true 911000000 911 false false Total investments and other assets No authoritative reference available. true 230 PROPERTY, PLANT AND EQUIPMENT 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 No definition available. false 231 Property, plant and equipment 2 us-gaap_PropertyPlantAndEquipmentGross us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 2294000000 2294 false false 2 false true 2216000000 2216 false false No definition available. No authoritative reference available. false 232 Accumulated depreciation 2 us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true -693000000 -693 false false 2 false true -666000000 -666 false false No definition available. No authoritative reference available. false 233 Net Property, Plant and Equipment 2 us-gaap_PropertyPlantAndEquipmentNet us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 1601000000 1601 false false 2 false true 1550000000 1550 false false No definition available. No authoritative reference available. true 234 TOTAL ASSETS 2 us-gaap_Assets us-gaap true debit instant monetary No definition available. false false false false false false false false false 1 false true 2844000000 2844 false false 2 false true 2809000000 2809 false false No definition available. No authoritative reference available. true 235 CURRENT LIABILITIES 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 No definition available. false 236 Short-term debt 2 us-gaap_ShortTermBorrowings us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 63000000 63 false false 2 false true 23000000 23 false false No definition available. No authoritative reference available. false 237 Current maturities of long-term debt 2 us-gaap_LongTermDebtCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 34000000 34 false false 2 false true 32000000 32 false false No definition available. No authoritative reference available. false 238 Accounts payable and accrued liabilities 2 us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 111000000 111 false false 2 false true 122000000 122 false false No definition available. No authoritative reference available. false 239 Accounts payable due to associated companies 2 us-gaap_AccountsPayableRelatedPartiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 28000000 28 false false 2 false true 28000000 28 false false No definition available. No authoritative reference available. false 241 Taxes accrued 2 us-gaap_TaxesPayableCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 2000000 2 false false 2 false true 7000000 7 false false No definition available. No authoritative reference available. false 242 Interest accrued 2 us-gaap_InterestPayableCurrent us-gaap true credit instant 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 No definition available. No authoritative reference available. false 243 Liabilities and accrued interest related to uncertain tax positions 2 us-gaap_LiabilityForUncertainTaxPositionsCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 6000000 6 false false No definition available. No authoritative reference available. false 245 Other 2 us-gaap_OtherLiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 39000000 39 false false 2 false true 35000000 35 false false No definition available. No authoritative reference available. false 246 Total Current Liabilities 2 us-gaap_LiabilitiesCurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 294000000 294 false false 2 false true 267000000 267 false false No definition available. No authoritative reference available. true 247 DEFERRED CREDITS 2 pom false na duration string Deferred Credits and Regulatory Liabilities [Abstract] false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false Deferred Credits and Regulatory Liabilities [Abstract] false 248 Regulatory liabilities 2 us-gaap_RegulatoryLiabilityNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 224000000 224 false false 2 false true 377000000 377 false false No definition available. No authoritative reference available. false 249 Deferred income taxes, net 2 us-gaap_DeferredTaxLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 593000000 593 false false 2 false true 549000000 549 false false No definition available. No authoritative reference available. false 250 Investment tax credits 2 us-gaap_AccumulatedDeferredInvestmentTaxCredit us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 9000000 9 false false 2 false true 10000000 10 false false No definition available. No authoritative reference available. false 253 Other postretirement benefit obligation 2 us-gaap_OtherPostretirementDefinedBenefitPlanLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 45000000 45 false false 2 false true 41000000 41 false false No definition available. No authoritative reference available. false 257 Other 2 us-gaap_OtherLiabilitiesNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 11000000 11 false false 2 false true 12000000 12 false false No definition available. No authoritative reference available. false 258 Total Deferred Credits 2 pom_TotalDeferredCreditsAndOtherLiabilities pom false credit instant monetary Total deferred credits and other liabilities. false false false false false false false false false 1 false true 882000000 882 false false 2 false true 989000000 989 false false Total deferred credits and other liabilities. No authoritative reference available. true 259 LONG-TERM LIABILITIES 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 No definition available. false 260 Long-term debt 2 us-gaap_LongTermDebtNoncurrent us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 609000000 609 false false 2 false true 610000000 610 false false No definition available. No authoritative reference available. false 261 Transition bonds issued by ACE Funding 2 us-gaap_LongTermTransitionBond us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 378000000 378 false false 2 false true 401000000 401 false false No definition available. No authoritative reference available. false 265 Total Long-Term Liabilities 2 pom_TotalOtherLongTermLiabilities pom false credit instant monetary Total Other Long-term Liabilities false false false false false false false false false 1 false true 987000000 987 false false 2 false true 1011000000 1011 false false Total Other Long-term Liabilities No authoritative reference available. true 266 COMMITMENTS AND CONTINGENCIES 2 us-gaap_CommitmentsAndContingencies2009 us-gaap true na duration string No definition available. false false false false false false false false false 1 false false 0 0 - false false 2 false false 0 0 - false false No definition available. No authoritative reference available. false 267 REDEEMABLE SERIAL PREFERRED STOCK 2 us-gaap_PreferredStockValueOutstanding us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 6000000 6 false false 2 false true 6000000 6 false false No definition available. No authoritative reference available. false 268 EQUITY 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 No definition available. false 269 Common stock 2 us-gaap_CommonStockValue us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 26000000 26 false false 2 false true 26000000 26 false false No definition available. No authoritative reference available. false 270 Premium on stock and other capital contributions 2 us-gaap_AdditionalPaidInCapitalCommonStock us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 474000000 474 false false 2 false true 344000000 344 false false No definition available. No authoritative reference available. false 272 Retained earnings 2 us-gaap_RetainedEarningsAccumulatedDeficit us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 175000000 175 false false 2 false true 166000000 166 false false No definition available. No authoritative reference available. false 273 Total Equity 2 us-gaap_StockholdersEquity us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 false true 675000000 675 false false 2 false true 536000000 536 false false No definition available. No authoritative reference available. true 276 TOTAL LIABILITIES AND EQUITY 2 us-gaap_LiabilitiesAndStockholdersEquity us-gaap true credit instant monetary No definition available. false false false false false false false false false 1 true true 2844000000 2844 false false 2 true true 2809000000 2809 false false No definition available. No authoritative reference available. true false 2 213 false Millions UnKnown UnKnown false true