2.2.0.25truefalse0606 - Disclosure - Pension and Other Postretirement Benefit Plans (Details)truefalseIn Millionsfalse1falsefalseUSDtruefalse{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Plans Defined Benefit [Member] 1/1/2011 - 3/31/2011 USD ($) $ThreeMonthsEnded_31Mar2011_Pension_Plans_Defined_Benefit_Memberhttp://www.sec.gov/CIK0001031296duration2011-01-01T00:00:002011-03-31T00:00:00falsefalsePension Benefit Cost (Credit)us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_PensionPlansDefinedBenefitMemberus-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2falsefalseUSDtruefalse{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Plans Defined Benefit [Member] 1/1/2010 - 3/31/2010 USD ($) $ThreeMonthsEnded_31Mar2010_Pension_Plans_Defined_Benefit_Memberhttp://www.sec.gov/CIK0001031296duration2010-01-01T00:00:002010-03-31T00:00:00falsefalsePension Benefit Cost (Credit)us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_PensionPlansDefinedBenefitMemberus-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1false0natruenanaNo definition available.falsetruefalsefalsefalsefalsefalsefalsefalsefalsehttp://firstenergycorp.com/role/pensionandotherpostretirementbenefitplansdetails1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse1falsefalseUSDtruefalse{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Plans Defined Benefit [Member] 1/1/2011 - 3/31/2011 USD ($) $ThreeMonthsEnded_31Mar2011_Pension_Plans_Defined_Benefit_Memberhttp://www.sec.gov/CIK0001031296duration2011-01-01T00:00:002011-03-31T00:00:00falsefalsePension Benefit Cost (Credit)us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_PensionPlansDefinedBenefitMemberus-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2falsefalseUSDtruefalse{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Plans Defined Benefit [Member] 1/1/2010 - 3/31/2010 USD ($) $ThreeMonthsEnded_31Mar2010_Pension_Plans_Defined_Benefit_Memberhttp://www.sec.gov/CIK0001031296duration2010-01-01T00:00:002010-03-31T00:00:00falsefalsePension Benefit Cost (Credit)us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_PensionPlansDefinedBenefitMemberus-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$OthernaNo definition available.No authoritative reference available.falsefalsePension Benefit Cost (Credit)2true0us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseComponents of Net Periodic Benefit Costs3false0us-gaap_DefinedBenefitPlanServiceCostus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse2900000029falsetruefalsefalsefalse2truefalsefalse2500000025falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 106 -Paragraph 518 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 87 -Paragraph 264 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph a, h falsefalseService cost4false0us-gaap_DefinedBenefitPlanInterestCostus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse8400000084falsefalsefalsefalsefalse2truefalsefalse7800000078falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 106 -Paragraph 518 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 87 -Paragraph 264 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph a, h falsefalseInterest cost5false0us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssetsus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse-102000000-102falsefalsefalsefalsefalse2truefalsefalse-90000000-90falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAn amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. 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