2.2.0.7 true Derivative Instruments (Details) (USD $) 00605 - Disclosure - Derivative Instruments (Details) true false In Millions false false 1 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 EPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ false 2 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 EPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 3 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 4 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 EPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 5 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 EPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 6 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ 5 Fair value of commodity derivatives 2 us-gaap_DerivativeFairValueOfDerivativeNetAbstract us-gaap true na duration No definition available. false false false false false true false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false 5 false false false false 0 0 false false false 6 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 8 Total Commodity Derivatives Assets 2 us-gaap_DerivativeAssetDesignatedAsHedgingInstrumentFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false totallabel false 1 true true false false 298000000 298 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 true true false false 298000000 298 false false false 5 false false false false 0 0 false false false 6 true true false false 233000000 233 false false false xbrli:monetaryItemType monetary Fair value of a derivative asset (or nonderivative instrument) that is designated and qualifies as a hedging instrument, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position. 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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph a -Clause 1 true 14 The effect of derivative instruments on the statements of income and comprehensive income for instruments designated in cash flow hedging relationships and not in hedging relationships 2 fe_EffectOfDerivativeInstrumentsOnStatementsOfIncomeAndComprehensiveIncomeForInstrumentsDesignatedInCashFlowHedgingRelationshipsAndNotInHedgingRelationshipsAbstract fe false na duration Effect of derivative instruments on statements of income and comprehensive income for instruments designated in cash flow... false false false false false true false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false 5 false false false false 0 0 false false false 6 false false false false 0 0 false false false xbrli:stringItemType string Effect of derivative instruments on statements of income and comprehensive income for instruments designated in cash flow hedging relationships and not in hedging relationships. false 15 Gain (Loss) Recognized in AOCL (Effective Portion) 2 us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet us-gaap true credit duration No definition available. false false false false false false false false false false false verboselabel false 1 false true false false -2000000 -2 false false false 2 false true false false 13000000 13 false false false 3 false false false false 0 0 false false false 4 false true false false -16000000 -16 false false false 5 false true false false 10000000 10 false false false 6 false false false false 0 0 false false false xbrli:monetaryItemType monetary The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph b -Clause 2 false 17 Unrealized Gain (Loss) Recognized in: 2 us-gaap_UnrealizedGainLossOnDerivatives us-gaap true credit duration No definition available. false false false false false false false false false false false verboselabel false 1 false true false false -158000000 -158 false false false 2 false true false false -23000000 -23 false false false 3 false false false false 0 0 false false false 4 false true false false -435000000 -435 false false false 5 false true false false -404000000 -404 false false false 6 false false false false 0 0 false false false xbrli:monetaryItemType monetary The increases (decreases) in the market value of derivative instruments, including options, swaps, futures, and forward contracts, which were included in earnings in the period. 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No authoritative reference available. false 19 Derivative Instruments (Textuals) [Abstract] 2 fe_DerivativeInstrumentsTextualsAbstract fe false na duration Derivative Instruments. false false false false false true false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false 5 false false false false 0 0 false false false 6 false false false false 0 0 false false false xbrli:stringItemType string Derivative Instruments. false 21 Decrease net income due to adverse change in commodity prices 2 fe_DecreaseNetIncomeDueToAdverseChangeInCommodityPrices fe false debit duration Decrease net income due to adverse change in commodity prices. false false false false false false false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false true false false 6000000 6 false false false 5 false false false false 0 0 false false false 6 false false false false 0 0 false false false xbrli:monetaryItemType monetary Decrease net income due to adverse change in commodity prices. 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No authoritative reference available. false 28 Decrease due to net hedge losses reclassified to earnings 2 fe_DecreaseDueToNetHedgeLossesReclassifiedToEarnings fe false debit duration Decrease due to net hedge losses reclassified to earnings. false false false false false false false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false true false false 10000000 10 false false false 5 false false false false 0 0 false false false 6 false false false false 0 0 false false false xbrli:monetaryItemType monetary Decrease due to net hedge losses reclassified to earnings. 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For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain or loss on that instrument. 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