Asset Retirement Obligation, Agreed Funding Period

No definition available.

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

- Definition

Asset Retirement Obligation, Escrow Deposit

+ References

No definition available.

+ Details

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

- Definition

Cash Collateral Received For Supply Contracts, Net

+ References

No definition available.

+ Details

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

- 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

Loss Contingency, Settlement Agreement, Term

+ References

No definition available.

+ Details

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

- Definition

Loss Contingency, Settlement Agreement, Term of Payments

+ References

No definition available.

+ Details

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

- Definition

Loss Contingency, Settlement Agreement, Will Not Be Recovered In Rates Or Charged to Customers

+ References

No definition available.

+ Details

Name:	fe_LossContingencySettlementAgreementWillNotBeRecoveredInRatesOrChargedToCustomers
Namespace Prefix:	fe_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1

Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 410
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Subparagraph (d)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481931/410-30-50-10

Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 410
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Subparagraph (d)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481931/410-30-50-10

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 410
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 16
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481899/410-30-55-16

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.Y.Q1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480102/450-20-S99-1

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 410
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481931/410-30-50-7

+ Details

Name:	us-gaap_AccrualForEnvironmentalLossContingencies
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-4

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-4

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-4

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-4

+ 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/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-4

+ Details

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

- Definition

Amount awarded to other party in judgment or settlement of litigation.

+ References

+ Details

Name:	us-gaap_LitigationSettlementAmountAwardedToOtherParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of loss (reversal of loss) recognized for loss contingency liability. Includes, but is not limited to, effect of revision in previously reported estimate.

+ References

+ Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	srt_LitigationCaseAxis=fe_UnitedStatesVHouseholderEtAlMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

COMMITMENTS, GUARANTEES AND CONTINGENCIES - Narrative (Details) - USD ($) $ in Millions	Mar. 04, 2025	Feb. 03, 2025	Jul. 21, 2021	Jun. 30, 2026	Dec. 31, 2024
Guarantor Obligations [Line Items]
Guarantor obligations				$ 1,051
Company posted collateral related to net liability positions				210
Collateral received				42
JCP&L
Guarantor Obligations [Line Items]
Guarantor obligations				50
Company posted collateral related to net liability positions				30
Collateral received				1
FET \| Letter of Credit
Guarantor Obligations [Line Items]
Guarantor obligations				102
United States v. Householder, et al. \| U.S. Attorney's Office
Guarantor Obligations [Line Items]
Term of DPA			3 years
Loss in period			$ 230
Term of payments			60 days
United States v. Householder, et al. \| United States Treasury
Guarantor Obligations [Line Items]
Amount of refunds announced			$ 115
United States v. Householder, et al. \| Ohio Development Service
Guarantor Obligations [Line Items]
Amount of refunds announced			115
Amount that won't be recovered in rates or charged to customers			$ 230
Regulation of Waste Disposal
Guarantor Obligations [Line Items]
Accrual for environmental loss contingencies				92
Environmental liabilities former gas facilities				66
Regulation of Waste Disposal \| JCP&L
Guarantor Obligations [Line Items]
Accrual for environmental loss contingencies				74
Environmental Liability
Guarantor Obligations [Line Items]
Asset retirement obligation, escrow deposit	$ 160	$ 160		$ 68	$ 130
Agreed funding period	5 years	5 years