1.0.0.3 false CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Millions false 1 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 2 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 3 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 4 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 5 NET INCOME 3 us-gaap_ProfitLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 230000000 230 false false 2 true true 471000000 471 false false 3 true true 754000000 754 false false 4 true true 1011000000 1011 false false No definition available. No authoritative reference available. false 6 OTHER COMPREHENSIVE INCOME (LOSS): 3 fe_OtherComprehensiveIncomeLossAbstract fe 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 7 Pension and other postretirement benefits 4 us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true -480000000 -480 false false 2 false true -20000000 -20 false false 3 false true 24000000 24 false false 4 false true -60000000 -60 false false No definition available. No authoritative reference available. false 8 Unrealized gain (loss) on derivative hedges 4 us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true 19000000 19 false false 2 false true 26000000 26 false false 3 false true 57000000 57 false false 4 false true 21000000 21 false false No definition available. No authoritative reference available. false 9 Change in unrealized gain on available-for-sale securities 4 us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -108000000 -108 false false 2 false true -100000000 -100 false false 3 false true -76000000 -76 false false 4 false true -181000000 -181 false false No definition available. No authoritative reference available. false 10 Other comprehensive income (loss) 4 us-gaap_OtherComprehensiveIncomeLossBeforeTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true -569000000 -569 false false 2 false true -94000000 -94 false false 3 false true 5000000 5 false false 4 false true -220000000 -220 false false No definition available. No authoritative reference available. true 11 Income tax expense (benefit) related to other comprehensive income 4 us-gaap_OtherComprehensiveIncomeLossTax us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -216000000 -216 false false 2 false true -34000000 -34 false false 3 false true 26000000 26 false false 4 false true -81000000 -81 false false No definition available. No authoritative reference available. false 12 Other comprehensive income (loss), net of tax 4 us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true -353000000 -353 false false 2 false true -60000000 -60 false false 3 false true -21000000 -21 false false 4 false true -139000000 -139 false false No definition available. No authoritative reference available. true 13 COMPREHENSIVE INCOME (LOSS) 3 us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -123000000 -123 false false 2 false true 411000000 411 false false 3 false true 733000000 733 false false 4 false true 872000000 872 false false No definition available. No authoritative reference available. true 14 LESS: COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO NONCONTROLLING INTEREST 3 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest 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 false 0 0 false false 3 false true -14000000 -14 false false 4 false true 1000000 1 false false No definition available. No authoritative reference available. false 15 COMPREHENSIVE INCOME (LOSS) AVAILABLE TO FIRSTENERGY CORP. 3 us-gaap_ComprehensiveIncomeNetOfTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true -119000000 -119 false false 2 true true 411000000 411 false false 3 true true 747000000 747 false false 4 true true 871000000 871 false false No definition available. No authoritative reference available. true false 4 11 false Millions UnKnown UnKnown false true