Bond Closure and Post Closure Period

No definition available.

Name:	fe_BondClosureandPostClosurePeriod
Namespace Prefix:	fe_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

-- None. No documentation exists for this element. --

+ References

No definition available.

+ Details

Name:	fe_CapitalInvestmentRequiredToInstallTechnologyToMeetTdsAndSulfateLimits
Namespace Prefix:	fe_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

- 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

- Definition

Commitment, Proposed Regulation, Waste Water Discharge Permit, Renewal Cycle

+ References

No definition available.

+ Details

Name:	fe_CommitmentProposedRegulationWasteWaterDischargePermitRenewalCycle
Namespace Prefix:	fe_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Company Posted Collateral Related To Net Liability Positions.

+ References

No definition available.

+ Details

Name:	fe_CompanyPostedCollateralRelatedToNetLiabilityPositions
Namespace Prefix:	fe_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Environmental Liabilities Former Gas Facilities.

+ References

No definition available.

+ Details

Name:	fe_EnvironmentalLiabilitiesFormerGasFacilities
Namespace Prefix:	fe_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

- Definition

Loss Contingency, Annual Contested Damage Claim

+ References

No definition available.

+ Details

Name:	fe_LossContingencyAnnualContestedDamageClaim
Namespace Prefix:	fe_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Loss Contingency, Annual Contested Damage Claim, Period

+ References

No definition available.

+ Details

Name:	fe_LossContingencyAnnualContestedDamageClaimPeriod
Namespace Prefix:	fe_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Loss Contingency, Mass Remaining Under Contract

+ References

No definition available.

+ Details

Name:	fe_LossContingencyMassRemainingUnderContract
Namespace Prefix:	fe_
Data Type:	num:massItemType
Balance Type:	na
Period Type:	instant

- 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

- Definition

Loss Contingency, Number of Installment Payments

+ References

No definition available.

+ Details

Name:	fe_LossContingencyNumberofInstallmentPayments
Namespace Prefix:	fe_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- 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

- Definition

Period to Complete Closure

+ References

No definition available.

+ Details

Name:	fe_PeriodtoCompleteClosure
Namespace Prefix:	fe_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Phases

+ References

No definition available.

+ Details

Name:	fe_Phases
Namespace Prefix:	fe_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Potential MATS Extension Period

+ References

No definition available.

+ Details

Name:	fe_PotentialMatsExtensionPeriod
Namespace Prefix:	fe_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- 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

- Definition

Total costs accrued as of the balance sheet date for environmental loss contingencies.

+ 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 410
-SubTopic 30
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 25
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346

+ Details

Name:	us-gaap_AccrualForEnvironmentalLossContingencies
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Decommission fund to pay for the costs of decontaminating and decommissioning of facilities through collection of revenues derived from utility assessments and government appropriations. Decommission fund investment for the process whereby a power station, at the end of its economic life, is taken permanently out of service and its site made available for other purposes. In the case of a nuclear station this comprises three different states of clearance. Immediately after the final closure, radioactive material such as nuclear fuel and operational waste is removed and the buildings surrounding the reactor shield are dismantled and finally the reactor itself is dismantled.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DecommissioningFundInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82913245&loc=d3e12069-110248

+ Details

Name:	us-gaap_GuaranteeObligationsCurrentCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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_GuaranteeObligationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=82913245&loc=d3e12069-110248

+ Details

Name:	us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

- 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

+ Details

Name:	us-gaap_LossContingencyLossInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	fe_LossContingenciesByClaimsAxis=fe_CleanWaterActMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fe_LossContingenciesByClaimsAxis=fe_RegulationOfWasteDisposalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fe_LossContingenciesByClaimsAxis=fe_NuclearPlantMattersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	fe_LossContingenciesByClaimsAxis=fe_CsaprMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=fe_RegulatedDistributionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=fe_FesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=fe_CompetitiveEnergyServicesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=fe_GlobalHoldingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	fe_BusinessUnitsAxis=fe_SignalPeakGlobalRailAndAffiliatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=fe_FevMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fe_BusinessUnitsAxis=fe_SignalPeakMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=fe_GlobalHoldingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=fe_WmbMarketingVenturesLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=fe_FirstEnergyGenerationLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=fe_AeSupplyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_RegulatoryAgencyAxis=fe_StateAndLocalAgenciesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_GuaranteedInsuranceContractTypeOfGuaranteeAxis=us-gaap_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteedInsuranceContractTypeOfGuaranteeAxis=us-gaap_SubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteedInsuranceContractTypeOfGuaranteeAxis=us-gaap_GuaranteeTypeOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteedInsuranceContractTypeOfGuaranteeAxis=fe_OtherAssurancesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis=fe_FirstEnergyNuclearGenerationLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_FinancialGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments, Guarantees and Contingencies (Details Textuals)				1 Months Ended	3 Months Ended	6 Months Ended
	May 01, 2017 USD ($) installment	Oct. 01, 2015	Aug. 03, 2015 T	Jun. 30, 2014	Mar. 31, 2017 USD ($)	Jun. 30, 2017 USD ($) phase T	Jun. 30, 2016	Dec. 31, 2016 USD ($)	Oct. 31, 2012 USD ($)
Guarantor Obligations [Line Items]
Outstanding guarantees and other assurances aggregated						$ 3,300,000,000
New syndicated senior secured term loan facility						$ 420,000,000
Proposed goal to reduce CO2 pollution (percent)						90.00%
Nuclear plant decommissioning trusts						$ 2,588,000,000		$ 2,514,000,000
Clean Water Act
Guarantor Obligations [Line Items]
Waste water discharge permit renewal cycle							5 years
Regulation of Waste Disposal
Guarantor Obligations [Line Items]
Bond closure and post closure period						45 years
Period to complete closure						12 years
Accrual for environmental loss contingencies						$ 131,000,000
Environmental liabilities former gas facilities						84,000,000
Nuclear Plant Matters
Guarantor Obligations [Line Items]
Nuclear plant decommissioning trusts						$ 2,600,000,000
Caa Compliance
Guarantor Obligations [Line Items]
Amount remaining under contract \| T						5,500,000
National Ambient Air Quality Standards
Guarantor Obligations [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
Guarantor Obligations [Line Items]
Number of phases under the EPA’s CAIR for reductions of Sulfur Dioxide and Mono-Nitrogen Oxides \| phase						2
Settled Litigation \| Caa Compliance
Guarantor Obligations [Line Items]
Loss recognized in period					$ 55,000,000
Regulated Distribution
Guarantor Obligations [Line Items]
Company posted collateral related to net liability positions						$ 4,000,000
FES
Guarantor Obligations [Line Items]
Company posted collateral related to net liability positions						123,000,000
New syndicated senior secured term loan facility						71,000,000
Nuclear plant decommissioning trusts						1,793,000,000		1,552,000,000
FES \| Caa Compliance
Guarantor Obligations [Line Items]
Annual contested damage claim						$ 70,000,000
Period of annual contested damage claim						11 years
FES \| Settled Litigation \| Caa Compliance
Guarantor Obligations [Line Items]
Loss recognized in period					$ 55,000,000
FES \| Competitive Energy Services
Guarantor Obligations [Line Items]
New syndicated senior secured term loan facility						$ 2,000,000
Global Holding \| Senior Secured Term Loan \| Senior Loans
Guarantor Obligations [Line Items]
New syndicated senior secured term loan facility						$ 300,000,000			$ 350,000,000
Global Holding \| Senior Secured Term Loan \| Senior Loans \| Signal Peak, Global Rail and Affiliates
Guarantor Obligations [Line Items]
Investment ownership percentage						69.99%
FEV \| Senior Secured Term Loan \| Senior Loans \| Signal Peak \| Global Holding
Guarantor Obligations [Line Items]
Investment ownership percentage						33.33%
WMB Marketing Ventures, LLC \| Senior Secured Term Loan \| Senior Loans \| Signal Peak \| Global Holding
Guarantor Obligations [Line Items]
Investment ownership percentage						33.33%
FG \| Settled Litigation \| Caa Compliance
Guarantor Obligations [Line Items]
Settlement amount	$ 109,000,000
AE Supply
Guarantor Obligations [Line Items]
Company posted collateral related to net liability positions						$ 0
New syndicated senior secured term loan facility						27,000,000
Environmental Protection Agency \| Caa Compliance
Guarantor Obligations [Line Items]
Period of time to implement plan		3 years
Minimum \| Clean Water Act
Guarantor Obligations [Line Items]
Maximum capital investment required to install technology to meet TDS and Sulfate limits						150,000,000
Minimum \| FES \| Caa Compliance
Guarantor Obligations [Line Items]
Number of installment payments \| installment	3
Maximum \| Clean Water Act
Guarantor Obligations [Line Items]
Maximum capital investment required to install technology to meet TDS and Sulfate limits						300,000,000
Maximum \| State and Local Agencies \| Climate Change
Guarantor Obligations [Line Items]
Potential MATS extension period				2 years
Certain Coal-Fired Power Plant \| FG \| Mercury and Air Toxic Standards
Guarantor Obligations [Line Items]
Minimum coal supply commitment (ton) \| T			3,500,000.0
Another Coal-Fired Power Plant \| FG \| Mercury and Air Toxic Standards
Guarantor Obligations [Line Items]
Minimum coal supply commitment (ton) \| T			2,500,000.0
FirstEnergy
Guarantor Obligations [Line Items]
Outstanding guarantees and other assurances aggregated						649,000,000
Subsidiaries
Guarantor Obligations [Line Items]
Outstanding guarantees and other assurances aggregated						1,900,000,000
Other Guarantee
Guarantor Obligations [Line Items]
Outstanding guarantees and other assurances aggregated						300,000,000
Other Assurances
Guarantor Obligations [Line Items]
Outstanding guarantees and other assurances aggregated						466,000,000
Line of Credit \| Revolving Credit Facility
Guarantor Obligations [Line Items]
Maximum amount borrowed under revolving credit facility						500,000,000
Line of Credit \| Revolving Credit Facility \| Nuclear Plant Matters
Guarantor Obligations [Line Items]
Maximum amount borrowed under revolving credit facility						$ 500,000,000
NG \| Financial Guarantee \| FES \| Nuclear Plant Matters
Guarantor Obligations [Line Items]
Outstanding guarantees and other assurances aggregated								$ 400,000,000