XML 75 R59.htm IDEA: XBRL DOCUMENT
v3.25.0.1

PENSION AND OTHER POSTEMPLOYMENT BENEFITS - Narrative (Details) $ in Millions |  | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
May 12, 2023 USD ($) | Jan. 31, 2025 USD ($) numberOfEmployee | Dec. 31, 2023 USD ($) numberOfEmployee | Jun. 30, 2023 USD ($) | Dec. 31, 2024 USD ($) | Dec. 31, 2023 USD ($) numberOfEmployee | Dec. 31, 2022 USD ($)
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |
Defined benefit plan, assumptions used calculating benefit obligation, increase (decrease) in discount rate |  |  |  |  | 0.67% |  |
Pensions and OPEB |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |
Pension & OPEB mark-to-market |  |  |  |  | $ 22 |  |
Pensions and OPEB | Integrated |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |
Mark-to-market adjustment, net of capitalized amounts |  |  |  |  | $ (8) | $ 36 | $ 15
Pension |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |
Weighted-average discount rate |  |  |  |  | 8.50% |  |
Expected future contributions |  |  |  |  | $ 300 |  |
Defined benefit plan, number of covered employees by plan | numberOfEmployee |  |  | 1,900 |  |  | 1,900 |
Defined benefit plan, plan assets pre tax gain |  |  | $ 36 |  |  |  |
Voluntary cash contribution | $ 750 |  |  |  |  |  |
Pre-tax pension mark-to-market adjustment gain |  |  |  | $ 59 | (66) | $ (108) | 98
Pension | Banner Life Insurance Company and Reinsurance Group of America |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |
Transfer of plan assets |  |  | (683) |  |  |  |
Transfer of benefit obligations |  |  | $ (719) |  |  |  |
Pension | MetLife | Subsequent Event |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |
Transfer of plan assets |  | $ 640 |  |  |  |  |
Transfer of benefit obligations |  | $ 652 |  |  |  |  |
Defined benefit plan, number of covered employees by plan | numberOfEmployee |  | 2,000 |  |  |  |  |
OPEB |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |
Pre-tax pension mark-to-market adjustment gain |  |  |  |  | $ 44 | $ 30 | $ (26)

X
- Definition Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Increase (Decrease) In Discount Rate + References No definition available. + Details
Name: | fe_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationIncreaseDecreaseInDiscountRate
Namespace Prefix: | fe_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Increase (Decrease) To Net Periodic Benefit Cost Based On Mark-To-Market Adjustment + References No definition available. + Details
Name: | fe_DefinedBenefitPlanIncreaseDecreaseToNetPeriodicBenefitCostBasedOnMarkToMarketAdjustment
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Defined Benefit Plan, Increase (Decrease) To Net Periodic Benefit Cost Based On Mark-To-Market Adjustments + References No definition available. + Details
Name: | fe_DefinedBenefitPlanIncreaseDecreaseToNetPeriodicBenefitCostBasedOnMarkToMarketAdjustments
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Defined Benefit Plan, Mark-To-Market Adjustment, Net + References No definition available. + Details
Name: | fe_DefinedBenefitPlanMarkToMarketAdjustmentNet
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Defined Benefit Plan, Number Of Covered Employees By Plan + References No definition available. + Details
Name: | fe_DefinedBenefitPlanNumberOfCoveredEmployeesByPlan
Namespace Prefix: | fe_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Defined Benefit Plan, Plan Assets Pre Tax Gain + References No definition available. + Details
Name: | fe_DefinedBenefitPlanPlanAssetsPreTaxGain
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Defined Benefit Plan, Voluntary Cash Contribution + References No definition available. + Details
Name: | fe_DefinedBenefitPlanVoluntaryCashContribution
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of increase (decrease) in plan assets of defined benefit plan from assets transferred into (from) plan. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanAssetsTransferredToFromPlan
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
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_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-18 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (g) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of increase (decrease) in benefit obligation of defined benefit plan from change in terms of existing plan or initiation of new plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(7) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanPlanAmendments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=fe_PensionPlansDefinedBenefitandOtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=fe_RegulatedTransmissionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fe_BannerLifeInsuranceCompanyAndReinsuranceGroupOfAmericaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fe_MetLifeMember
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: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |