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

Litigation Indictment, Number Of Senior Officers

+ References

No definition available.

+ Details

Name:	fe_LitigationIndictmentNumberOfSeniorOfficers
Namespace Prefix:	fe_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Litigation Settlement, Amount Awarded, Net Return On Deposited Funds

+ References

No definition available.

+ Details

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

- 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

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

Amount of asset retirement obligations incurred during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481850/410-20-50-1

+ Details

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

- Definition

Amount of increase (decrease) in asset retirement obligations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481850/410-20-50-1

+ Details

Name:	us-gaap_AssetRetirementObligationPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Indicates line item in statement of financial position that includes accrual for environmental loss contingency.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.Y.Q4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480102/450-20-S99-1

Reference 2: 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

+ Details

Name:	us-gaap_EnvironmentalLossContingencyStatementOfFinancialPositionExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
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 from other party in judgment or settlement of litigation.

+ References

No definition available.

+ Details

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

- 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

- Definition

Amount of increase (decrease) in loss contingency liability.

+ References

+ Details

Name:	us-gaap_LossContingencyAccrualCarryingValuePeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
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

- Definition

The amount of cash paid for the settlement of litigation or for other legal issues during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 25
-Subparagraph (g)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-25

+ Details

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

- 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:	srt_LitigationCaseAxis=fe_ShareholderDerivativeLawsuitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=fe_UnitedStatesV.HouseholderEtAl.RelatedOOCICInvestigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=fe_UnitedStatesV.HouseholderEtAl.RelatedSECInvestigationMember
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:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_CorporateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

COMMITMENTS, GUARANTEES AND CONTINGENCIES - Narrative (Details) $ in Millions					3 Months Ended	12 Months Ended
	Feb. 03, 2025 USD ($)	Sep. 25, 2024 USD ($)	Feb. 09, 2022 USD ($)	Jul. 21, 2021 USD ($)	Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)	Feb. 12, 2024 officer
Guarantor Obligations [Line Items]
Total Guarantees and Other Assurances						$ 923.0
Company posted collateral related to net liability positions						170.0
Collateral received						29.0
Liabilities incurred						$ 95.0
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]						Regulatory liabilities
United States v. Householder, et al.
Guarantor Obligations [Line Items]
Litigation indictment, number of senior officers \| officer							2
United States v. Householder, et al. \| U.S. Attorney's Office
Guarantor Obligations [Line Items]
Term of DPA				3 years
Loss in period				$ 230.0
Term of payments				60 days
United States v. Householder, et al. \| United States Treasury
Guarantor Obligations [Line Items]
Proposed penalty				$ 115.0
United States v. Householder, et al. \| Ohio Development Service
Guarantor Obligations [Line Items]
Proposed penalty				$ 115.0
Shareholder Derivative Lawsuit
Guarantor Obligations [Line Items]
Proposed penalty			$ 36.0
Settlement payment awarded			180.0
Litigation settlement, amount awarded, net return on deposited funds			$ 7.0
United States v. Householder, et al. Related OOCIC Investigation
Guarantor Obligations [Line Items]
Loss contingency accrual, period increase (decrease)					$ 19.5
United States v. Householder, et al. Related SEC Investigation
Guarantor Obligations [Line Items]
Payments for legal settlements		$ 100.0
Loss contingency accrual, period increase (decrease)					100.0
Regulation of Waste Disposal
Guarantor Obligations [Line Items]
Changes in timing and amount of estimated cash flows					139.0	$ 139.0
Accrual for environmental loss contingencies						98.0
Environmental liabilities former gas facilities						$ 69.0
Regulation of Waste Disposal \| Corporate Non Segment
Guarantor Obligations [Line Items]
Liabilities incurred					$ 87.0
Environmental Liability \| Subsequent Event
Guarantor Obligations [Line Items]
Asset retirement obligation, escrow deposit	$ 160.0
Agreed funding period	5 years