XML 148 R129.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Commitments, Guarantees and Contingencies - Clean Air Act and Climate Change (Details) $ in Millions |  |  |  |  | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | ---
Feb. 18, 2018 USD ($) | May 01, 2017 USD ($) | Oct. 01, 2015 | Aug. 03, 2015 T | Mar. 31, 2017 USD ($) | Dec. 31, 2017 phase T | Nov. 12, 2014
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Proposed reduction in power plants carbon pollution (percent) |  |  |  |  |  | 90.00% |
National Ambient Air Quality Standards |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Capping of SO2 Emissions Under CSAPR | T |  |  |  |  |  | 2,400,000 |
Capping of NOx emissions under CSAPR | T |  |  |  |  |  | 1,200,000 |
National Ambient Air Quality Standards | CSAPR |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Number of phases under the EPA’s CAIR for reductions of Sulfur Dioxide and Mono-Nitrogen Oxides | phase |  |  |  |  |  | 2 |
Mercury and Air Toxic Standards | FG | Certain Coal-Fired Power Plant |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Contractual amount in dispute (in T) | T |  |  |  | 3,500,000.0 |  |  |
Mercury and Air Toxic Standards | FG | Another Coal-Fired Power Plant |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Contractual amount in dispute (in T) | T |  |  |  | 2,500,000.0 |  |  |
Minimum | Climate Change |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Reduction in emissions (percent) |  |  |  |  |  |  | 26.00%
Maximum | Climate Change |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Reduction in emissions (percent) |  |  |  |  |  |  | 28.00%
EPA | Caa Compliance |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Period of time to implement plan |  |  | 3 years |  |  |  |
Signal Peak, Global Rail and Affiliates | Senior Secured Term Loan | Senior Loans | Global Holding |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Investment ownership percentage |  |  |  |  |  | 69.99% |
Settled Litigation | Caa Compliance |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loss in period |  |  |  |  | $ 116 |  |
Settled Litigation | Caa Compliance | FG |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Amount of damages awarded |  | $ 109 |  |  |  |  |
Settled Litigation | Caa Compliance | FES |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loss in period |  |  |  |  | $ 116 |  |
Subsequent Event |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Amount of damages awarded to other party | $ 93 |  |  |  |  |  |
Subsequent Event | AE Supply |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Amount of damages awarded to other party | $ 93 |  |  |  |  |  |

X
- Definition Capping Of Gas One Emissions Under Cross State Air Pollution Rule + References No definition available. + Details
Name: | fe_CappingOfGasOneEmissionsUnderCrossStateAirPollutionRule
Namespace Prefix: | fe_
Data Type: | num:massItemType
Balance Type: | na
Period Type: | duration

X
- Definition Capping Of Gas Two Emissions Under Cross State Air Pollution Rule + References No definition available. + Details
Name: | fe_CappingOfGasTwoEmissionsUnderCrossStateAirPollutionRule
Namespace Prefix: | fe_
Data Type: | num:massItemType
Balance Type: | na
Period Type: | duration

X
- Definition Investment, Ownership Percentage Pledged as Collateral + References No definition available. + Details
Name: | fe_InvestmentOwnershipPercentagePledgedAsCollateral
Namespace Prefix: | fe_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Loss Contingency, Nonmonetary Contractual Amount in Dispute, Mass + References No definition available. + Details
Name: | fe_LossContingencyNonmonetaryContractualAmountinDisputeMass
Namespace Prefix: | fe_
Data Type: | num:massItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period of Time to Implement Plan + References No definition available. + Details
Name: | fe_PeriodOfTimeToImplementPlan
Namespace Prefix: | fe_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Phases + References No definition available. + Details
Name: | fe_Phases
Namespace Prefix: | fe_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Proposed Action, Reduction in Power Plants Carbon Pollution, Percentage + References No definition available. + Details
Name: | fe_ProposedActionReductioninPowerPlantsCarbonPollutionPercentage
Namespace Prefix: | fe_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Proposed Regulation, Reduction in Emissions, Percent + References No definition available. + Details
Name: | fe_ProposedRegulationReductioninEmissionsPercent
Namespace Prefix: | fe_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount awarded to other party in judgment or settlement of litigation. + References No definition available. + Details
Name: | us-gaap_LitigationSettlementAmountAwardedToOtherParty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_LossContingenciesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of damages awarded to the plaintiff in the legal matter. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14557-108349 + Details
Name: | us-gaap_LossContingencyDamagesAwardedValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of loss pertaining to the specified contingency that was charged against earnings in the period, including the effects of revisions in previously reported estimates. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349 + Details
Name: | us-gaap_LossContingencyLossInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=fe_NationalAmbientAirQualityStandardsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | fe_LossContingenciesByClaimsAxis=fe_CsaprMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=fe_MercuryandAirToxicStandardsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=fe_FirstEnergyGenerationLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=fe_CertainCoalFiredPowerPlantMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=fe_AnotherCoalFiredPowerPlantMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=fe_ClimateChangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAgencyAxis=fe_EnvironmentalProtectionAgencyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=fe_CaaComplianceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | fe_BusinessUnitsAxis=fe_SignalPeakGlobalRailAndAffiliatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=fe_SeniorSecuredTermLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=fe_GlobalHoldingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LitigationStatusAxis=us-gaap_SettledLitigationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=fe_FesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=fe_AeSupplyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |