Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] Maximum Maximum [Member] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Title of 12(b) Security Title of 12(b) Security Subsequent Event Subsequent Event [Member] Number of EDC's Number Of Electric Distribution Service Companies Number Of Electric Distribution Service Companies Carrying value Reported Value Measurement [Member] Schedule of Available-for-sale Securities [Table] Debt Securities, Available-for-Sale [Table] Adjustment to Compensation, Amount Adjustment to Compensation Amount Financial Instrument [Axis] Financial Instrument [Axis] Cash collateral, net Cash collateral, net Increase (Decrease ) In Collateral Increase (Decrease ) In Collateral Other Other Assets, Fair Value Disclosure Segment Reporting [Abstract] Segment Reporting [Abstract] Convertible Notes Maturity 2029 Convertible Notes Maturity 2029 [Member] Convertible Notes Maturity 2029 Stock Investment Plan and share-based benefit plans (in shares) Stock Issued During Period, Shares, Stock Investment And Employee Benefit Plan Stock Issued During Period, Shares, Stock Investment And Employee Benefit Plan State and municipal income taxes, net of federal effect Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent PENSION AND OTHER POST-EMPLOYMENT BENEFITS Retirement Benefits [Text Block] Other affiliate support services Other Affiliate Support Services [Member] Other Affiliate Support Services Guarantor obligations Guarantor Obligations, Maximum Exposure, Undiscounted 2024-2030 EmPOWER Program Cycle 2024-2030 EmPOWER Program Cycle [Member] 2024-2030 EmPOWER Program Cycle Unsecured Senior Notes Due 2029 Unsecured Senior Notes Due 2029 [Member] Unsecured Senior Notes Due 2029 Measurement Frequency [Axis] Measurement Frequency [Axis] Debt instrument, conversion price (in dollars per share) Debt Instrument, Convertible, Conversion Price Consolidated Entities [Axis] Consolidated Entities [Axis] Public utilities, penalty imposed Public Utilities, Penalty For Failure To Perform Electric Service Reliability Performance Has Been Imposed. Public Utilities, Penalty For Failure To Perform Electric Service Reliability Performance Has Been Imposed. Entity Common Stock Shares Outstanding Entity Common Stock, Shares Outstanding Tax related to FE's equity investment in FET Effective Income Tax Rate Reconciliation, Equity in Earnings (Losses) of Unconsolidated Subsidiary, Percent Receivables Billing Status [Domain] Receivables Billing Status [Domain] Capitalized cost of equity Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity Percent Effective Income Tax Rate Reconciliation, Percent [Abstract] Other operating expense Other Cost of Operating Revenue Amount that won't be recovered in rates or charged to customers Loss Contingency, Settlement Agreement, Will Not Be Recovered In Rates Or Charged to Customers Loss Contingency, Settlement Agreement, Will Not Be Recovered In Rates Or Charged to Customers Public utilities, approved energy consumption reduction targets, cost recovery Public Utilities, Approved Energy Consumption Reduction Targets, Cost Recovery Public Utilities, Approved Energy Consumption Reduction Targets, Cost Recovery Refund amount received Public Utilities, Refund Amount Received Public Utilities, Refund Amount Received TRANSACTIONS WITH AFFILIATES Related Party Transactions Disclosure [Text Block] Consolidated Entities [Domain] Consolidated Entities [Domain] TrAIL TrAIL [Member] TRAIL. Shelf Registration Statement Shelf Registration Statement [Member] Shelf Registration Statement Debt instrument, measurement period percentage Debt Instrument, Convertible, Threshold Percentage Of Stock Trading Price Debt Instrument, Convertible, Threshold Percentage Of Stock Trading Price Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share NONCURRENT LIABILITIES: NONCURRENT LIABILITIES: Liabilities, Noncurrent [Abstract] 4.55% Unsecured Senior Notes Maturing 2031 4.55% Unsecured Senior Notes Maturing 2031 [Member] 4.55% Unsecured Senior Notes Maturing 2031 Retirement Benefits [Abstract] Retirement Benefits [Abstract] Investments Investments Long-Term Investments Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Fair Value of Financial Instruments [Table] Fair Value of Financial Instruments [Table] Fair Value Of Financial Instruments. Beginning balance Ending balance Asset Retirement Obligation Number of reportable segments Number of Reportable Segments Total current liabilities Liabilities, Current Public utilities, requested cost percentage, year two Public Utilities, Requested Cost Percentage, Year Two Public Utilities, Requested Cost Percentage, Year Two U.S. Attorney's Office U.S. Attorney's Office [Member] U.S. Attorney's Office Consolidated debt to total capitalization ratio (percent) Line of Credit Facility, Covenant Terms, Debt to Capitalization Ratio Line of Credit Facility, Covenant Terms, Debt to Capitalization Ratio Entity Address, City or Town Entity Address, City or Town Cross-default provision for other indebtedness Debt Instrument, Subjective Acceleration Clause, Cross-Default, Amount Debt Instrument, Subjective Acceleration Clause, Cross-Default, Amount 2024-2026 EmPOWER Program Cycle 2024-2026 EmPOWER Program Cycle [Member] 2024-2026 EmPOWER Program Cycle Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Unbilled Unbilled Revenues [Member] Grid Growth Grid Growth [Member] Grid Growth Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Jcp And L Jcp And L [Member] Jersey Central Power & Light Company. Conversion premium Debt Instrument, Convertible, Conversion Premium Debt Instrument, Convertible, Conversion Premium Level 2 Fair Value, Inputs, Level 2 [Member] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Less — Accumulated provision for depreciation Less — Accumulated provision for depreciation Public Utilities, Property, Plant and Equipment, Accumulated Depreciation, Excluding Construction Work in Progress Public Utilities, Property, Plant and Equipment, Accumulated Depreciation, Excluding Construction Work in Progress Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] FE FE’s Guarantees on Behalf of its Consolidated Subsidiaries Parent Company [Member] Tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Percent Subsequent Event Type [Axis] Subsequent Event Type [Axis] Deferred regulatory asset and recovered rate Public Utilities, Temporary Rate Credit, Recovery Amount Per Bill Public Utilities, Temporary Rate Credit, Recovery Amount Per Bill Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Schedule of Segment Financial Information Segment Reporting [Table Text Block] Redemptions and repayments- Redemptions And Repayments [Abstract] Redemptions And Repayments Abstract. Impairment of assets Impairment of Long-Lived Assets to be Disposed of Related Party [Axis] Related and Nonrelated Parties [Axis] Guaranteed Insurance Contract, Type of Guarantee [Domain] Guaranteed Insurance Contract, Type of Guarantee [Domain] Guarantor Obligations [Line Items] Guarantor Obligations [Line Items] Significant non-cash transactions: Significant non-cash transactions: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Document Period End Date Document Period End Date Public utilities, requested rate increase, estimated initial investment Public Utilities, Requested Rate Increase, Estimated Initial Investment Public Utilities, Requested Rate Increase, Estimated Initial Investment Debt instrument convertible premium Debt Instrument Convertible, Conversion Price, Premium Debt Instrument Convertible, Conversion Price, Premium Face amount of debt Debt Instrument, Face Amount Ohio settlement customer restitution and refunds (Note 9.) Increase (Decrease) in Ohio Settlement Customer Restitution and Refunds Increase (Decrease) in Ohio Settlement Customer Restitution and Refunds New Jersey ZEC refund, net (Note 9.) New Jersey ZEC refund, net (Note 9.) New Jersey Zero Emissions Certificate Refunds, Net New Jersey Zero Emissions Certificate Refunds, Net Accumulated other comprehensive loss Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company Consolidation Items [Domain] Consolidation Items [Domain] Schedule of Activity in the Allowance for Uncollectible Accounts on Customer Receivables Accounts Receivable, Allowance for Credit Loss [Table Text Block] EARNINGS PER SHARE OF COMMON STOCK Earnings Per Share [Text Block] EARNINGS PER SHARE ATTRIBUTABLE TO FIRSTENERGY CORP. (Note 3.): Earnings Per Share [Abstract] Earnings Per Share [Abstract] Document Fiscal Period Focus Document Fiscal Period Focus Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] TOTAL LIABILITIES Liabilities Liabilities Liabilities Trading Symbol Trading Symbol Realized gains Debt and Equity Securities, Realized Gains Debt and Equity Securities, Realized Gains Accrued taxes Accrued taxes Accrued Income Taxes, Current Company Selected Measure Name Company Selected Measure Name Sale of Stock [Domain] Sale of Stock [Domain] Purchases of investment securities held in trusts Purchases of investment securities held in trusts Payments to Acquire Debt Securities, Available-for-Sale Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Employee benefit plan funding and related payments Employee benefit plan funding and related payments Pension And Other Postretirement Benefits, Contributions And Related Payments Pension And Other Postretirement Benefits, Contributions And Related Payments Property, Plant and Equipment [Table] Regulated Operation, Regulatory Asset [Table] Billed Billed Revenues [Member] Changes in unrecognized tax benefits Effective Income Tax Rate Reconciliation, Tax Contingency, Percent Brookfield Brookfield [Member] Brookfield Number of customers Number Of Customers Number Of Customers. Other, net of allowance for uncollectible accounts of $11 in 2026 and 2025 Other Receivables, Net, Current Public Utility [Axis] Public Utility [Axis] Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] PUCO Public Utilities Commission Of Ohio [Member] Public Utilities Commission Of Ohio [Member] Asset retirement obligation, escrow deposit Asset Retirement Obligation, Escrow Deposit Asset Retirement Obligation, Escrow Deposit Deferred income taxes and investment tax credits, net Deferred income taxes and investment tax credits, net Deferred Income Taxes and Tax Credits Dividends payable Dividends Payable Other revenue from contracts with customers Other Services [Member] Other Services [Member] Award Timing Predetermined Award Timing Predetermined [Flag] Total property, plant and equipment Property, plant and equipment Public Utilities, Property, Plant and Equipment, Net Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Stock-based compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Level 1 Fair Value, Inputs, Level 1 [Member] Tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Amount Per Year 2033-2035 Program Cycle Per Year 2033-2035 Program Cycle [Member] Per Year 2033-2035 Program Cycle Total income taxes Effective Income Tax Rate Reconciliation, Percent Debt instrument, convertible, conversion ratio Debt Instrument, Convertible, Conversion Ratio Transmission revenue collections, net Transmission revenue collections, net Transmission Revenue Collection, Net Transmission Revenue Collection, Net Public utilities, conversion plan period Public Utilities, Conversion Plan Period Public Utilities, Conversion Plan Period PN Pennsylvania Electric Company [Member] Pennsylvania Electric Company Liabilities incurred Asset Retirement Obligation, Liabilities Incurred Alternative Revenue Program Alternative Revenue Program [Member] Alternative Revenue Program Assumed exercise of dilutive share-based awards (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Loss Contingencies By Claims [Domain] Loss Contingencies By Claims [Domain] Loss Contingencies By Claims. Three-Year Rate Plan, Revenue Increases in Year Two Three-Year Rate Plan, Revenue Increases in Year Two [Member] Three-Year Rate Plan, Revenue Increases in Year Two Regulated Operations [Abstract] Regulated Operations [Abstract] 4.00%, $294 Million Notes Maturity 2026 4.00%, $294 Million Notes Maturity 2026 [Member] 4.00%, $294 Million Notes Maturity 2026 Transmission Transmission [Member] Transmission Provision for depreciation Provision for depreciation Depreciation Depreciation Percent of face amount of debt Guarantor Obligations, Maximum Contractual Obligations, Percent of Face Amount of Debt Guarantor Obligations, Maximum Contractual Obligations, Percent of Face Amount of Debt Transmission solutions to the reliability issues Public Utilities, Transmission Solutions To The Reliability Issues, Amount Public Utilities, Transmission Solutions To The Reliability Issues, Amount Antidilutive Securities [Axis] Antidilutive Securities [Axis] Vehicle leases Vehicle Leases [Member] Vehicle Leases Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] EnergizeNJ Energy Efficiency and Peak Demand Reduction [Member] Energy Efficiency and Peak Demand Reduction Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Energy Efficiency and Peak Demand Reduction Stipulation Settlement Energy Efficiency and Peak Demand Reduction Stipulation Settlement [Member] Energy Efficiency and Peak Demand Reduction Stipulation Settlement Currently payable long-term debt Currently payable long-term debt Long-Term Debt and Lease Obligation, Current Common stock dividend payments Common stock dividend payments Payments of Ordinary Dividends, Common Stock Expiration Date Trading Arrangement Expiration Date JCP And L JCP And L [Member] Jersey Central Power & Light Company. FESC support services FESC Support Services [Member] FESC Support Services Short-term cash investments Cash and Cash Equivalents, Fair Value Disclosure TOTAL EQUITY Beginning balance Ending balance Equity, Including Portion Attributable to Noncontrolling Interest FERC Federal Energy Regulatory Commission [Member] Federal Energy Regulatory Commission Environmental Liability Environmental Liability [Member] Environmental Liability Nonrelated Party Nonrelated Party [Member] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] EPS Attributable to FE: Earnings Per Share Reconciliation [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Security, Excluded EPS Calculation [Table] Receivables Receivables Increase (Decrease) in Accounts and Other Receivables FE PA FE PA [Member] FE PA Corporate AMT credit carryforwards Deferred Tax Assets, Corporate AMT Credit Carryforwards Deferred Tax Assets, Corporate AMT Credit Carryforwards North American Transmission Company II LLC North American Transmission Company II LLC [Member] North American Transmission Company II LLC Cash Flows from Investing Activities: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Related Party Transaction [Axis] Related Party Transaction [Axis] Estimated initial investment Public Utilities Estimated Initial Investment Public Utilities Estimated Initial Investment Variable interest entities percentage of high voltage transmission line project owned by variable interest entity one in joint venture party two Variable Interest Entities Percentage Of High Voltage Transmission Line Project Owned By Variable Interest Entity One In Joint Venture Party Two Variable Interest Entities Percentage of high voltage transmission line project owned By variable interest entity one in joint venture party two. Segments [Domain] Segments [Domain] Asset Retirement Obligation [Line Items] Asset Retirement Obligation [Line Items] Asset Retirement Obligation Potential Collateral Obligations Contractual Obligation Unsecured Senior Notes Due 2028 Unsecured Senior Notes Due 2028 [Member] Unsecured Senior Notes Due 2028 Convertible Notes 2026 Convertible Notes 2026 [Member] Convertible Notes 2026 Interest expense Interest expense Interest Costs Incurred PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Total operating expenses Total operating expenses Costs and Expenses Service area Service Area Service Area. Issuance interest rate Debt Instrument, Interest Rate, Stated Percentage Total common stockholders’ equity Beginning balance Ending balance Equity, Attributable to Parent ASSETS ASSETS Assets [Abstract] Cost Basis Debt Securities, Available-for-Sale, Amortized Cost Transmission rate, base ROE Public Utilities, Requested Return on Equity, Percentage Insider Trading Policies and Procedures [Line Items] Less — Allowance for uncollectible customer receivables Allowance for uncollectible accounts Less: Uncollectible Reserve Accounts Receivable, Allowance for Credit Loss, Current Solar Generation Project Solar Generation Project [Member] Solar Generation Project Antidilutive securities excluded from computation of EPS (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Entity Central Index Key Entity Central Index Key Grid Growth EHV Holdings, LLC Grid Growth EHV Holdings, LLC [Member] Grid Growth EHV Holdings, LLC Term of DPA Loss Contingency, Settlement Agreement, Term Loss Contingency, Settlement Agreement, Term Amortization period Recovery Program, Amortization Period Recovery Program, Amortization Period Other paid-in capital Other paid-in capital Additional Paid in Capital, Common Stock Schedule of Guarantor Obligations [Table] Guarantor Obligation [Table] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Percent of subscriptions required prior to commencement of construction Public Utilities, Plant Construction, Percent of Subscriptions Required Prior To Commencement Public Utilities, Plant Construction, Percent of Subscriptions Required Prior To Commencement Federal statutory income tax Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Stock Investment Plan and share-based benefit plans Stock Issued During Period, Value, Stock Investment And Employee Benefit Plan Stock Issued During Period, Value, Stock Investment And Employee Benefit Plan Ownership [Axis] Ownership [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Investment, Name [Axis] Investment, Name [Axis] Amount Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract] Fair value and related carrying amounts of long-term debt and other long-term obligations Fair value and related carrying amounts of long term debt and other long term obligations [Abstract] Fair value and related carrying amounts of long-term debt and other long-term obligations. Debt instrument, basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Capitalized financing costs Capitalized financing costs Interest Costs Capitalized Adjustment Variable Rate [Domain] Variable Rate [Domain] AOCI AOCI AOCI Attributable to Parent [Member] All Individuals All Individuals [Member] As Reported Previously Reported [Member] Energy Efficiency and Conservation Phase V Energy Efficiency and Conservation Phase V [Member] Energy Efficiency and Conservation Phase V Statement [Line Items] Statement [Line Items] TOTAL ASSETS Assets Total assets Assets 5.02% Unsecured Senior Notes Maturing 2036 5.02% Unsecured Senior Notes Maturing 2036 [Member] 5.02% Unsecured Senior Notes Maturing 2036 Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plan [Table] Amount of energy looking to be procured (in MW's) Public Utilities, Announced Procurement Plan, In Megawatts Public Utilities, Announced Procurement Plan, In Megawatts Senior Unsecured Convertible Notes Convertible Debt [Member] Variable Interest Entity, Not Primary Beneficiary Variable Interest Entity, Not Primary Beneficiary [Member] Operating Segments Operating Segments [Member] Interest expense Interest Expense, Nonoperating Unrealized Gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Winter Storm Fern deferred purchase power costs, net (Note 9.) Charges incurred Deferred Purchase Power Costs, Net Deferred Purchase Power Costs, Net PEO PEO [Member] Other Other Other Liabilities, Noncurrent Goodwill Goodwill Total goodwill Goodwill Retirement Plan Type [Axis] Retirement Plan Type [Axis] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Recovery period for expenditures for cost recovery program Recovery Period For Expenditures For Cost Recovery Program Recovery period for expenditures for cost recovery program. Changes in unrecognized tax benefits Effective Income Tax Rate Reconciliation, Tax Contingency, Amount Convertible Notes Maturity 2031 Convertible Notes Maturity 2031 [Member] Convertible Notes Maturity 2031 Retained Earnings Retained Earnings Retained Earnings [Member] Fair Value Measurement Fair Value Measurement, Policy [Policy Text Block] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common stock, outstanding (in shares) Beginning balance (in shares) Ending balance (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Diluted (in dollars per share) Diluted EPS (in dollars per share) Earnings Per Share, Diluted Prepaid taxes and other current assets Prepaid taxes and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Capitalized interest Interest Costs Capitalized Accrued compensation and benefits Accrued compensation and benefits Increase (Decrease) in Employee Related Liabilities Litigation Case [Domain] Litigation Case [Domain] Capped portion of surety bond obligations Guarantor Obligations, Capped Portion of Surety Bond Obligations Guarantor Obligations, Capped Portion of Surety Bond Obligations Transfer of McElroy’s Run CCR impoundment facility McElroy Run Transfer [Member] McElroy Run Transfer Ownership [Domain] Ownership [Domain] Estimated refund obligation Public Utilities, Estimated Refund Obligation Public Utilities, Estimated Refund Obligation Request to remove basis point adder Utilities, Request To Remove Basis Point Adder Associated With RTO Membership Utilities, Request To Remove Basis Point Adder Associated With RTO Membership Ownership interest Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest Surety bonds Surety bonds (collateralized amount) Surety Bond [Member] Unsecured Senior Notes Due 2036 Unsecured Senior Notes Due 2036 [Member] Unsecured Senior Notes Due 2036 Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Accrued interest Accrued interest Increase (Decrease) in Interest Payable, Net Other current liabilities Other current liabilities Increase (Decrease) in Other Current Liabilities State and municipal income taxes, net of federal effect Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Sale of Stock [Axis] Sale of Stock [Axis] Allocated net periodic benefit costs from affiliates Defined Benefit Plan, Net Periodic Benefit Cost, Allocated From Affiliates Defined Benefit Plan, Net Periodic Benefit Cost, Allocated From Affiliates CASH FLOWS FROM OPERATING ACTIVITIES: CASH FLOWS FROM OPERATING ACTIVITIES: CASH FLOWS FROM OPERATING ACTIVITIES: Cash Provided by (Used in) Operating Activity, Continuing Operation [Abstract] Capital structure, debt Public Utilities, Approved Debt Capital Structure, Percentage OTHER INCOME (EXPENSE): OTHER INCOME (EXPENSE): Other Nonoperating Income (Expense) [Abstract] OPERATING INCOME Operating income Operating Income (Loss) Proceeds from issuance of debt Proceeds from Issuance of Debt Recovery of project abandonment costs (percent) Public Utilities, Recovery Of Project Abandonment, Prior To Effective Date Costs, Percentage Public Utilities, Recovery Of Project Abandonment, Prior To Effective Date Costs, Percentage Related Party Transaction [Domain] Related Party Transaction [Domain] Cash dividends declared on common stock Cash dividends declared on common stock Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings PJM 2024 RTEP Window 1 PJM 2024 RTEP Window 1 [Member] PJM 2024 RTEP Window 1 Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Service costs Defined Benefit Plan, Service Cost Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] FET FET [Member] FET Proceeds from the sale of investments in available-for-sale securities, realized gains and losses on those sales, and interest and dividend income Debt Securities, Available-for-Sale, Realized Gain (Loss) [Abstract] Transmission services available area populations Transmission Services Available Area Populations Transmission Services Available Area Populations Fair Value of Financial Instruments [Line Items] Fair Value of Financial Instruments [Line Items] Fair Value of Financial Instruments. Schedule of Potential Collateral Obligations Schedule of Guarantor Obligations [Table Text Block] Adjustment Revision of Prior Period, Adjustment [Member] Product and Service [Domain] Product and Service [Domain] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] EQUITY: Capitalization, Long-Term Debt and Equity [Abstract] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Accumulated deferred income taxes Accumulated deferred income taxes, net Deferred Income Tax Liabilities, Net Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Termination Date Trading Arrangement Termination Date Transmission ROE Incentive Transmission ROE Incentive [Member] Transmission ROE Incentive Amortization (deferral) of regulatory assets, net Amortization (Deferral) Of Regulatory Assets, Net Amortization (Deferral) Of Regulatory Assets, Net Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Federal statutory income tax Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Other Other Other Liabilities, Current WVPSC Public Service Commission of West Virginia [Member] Public Service Commission of West Virginia [Member] Fair Value as of Grant Date Award Grant Date Fair Value Per Year 2030-2032 Program Cycle Per Year 2030-2032 Program Cycle [Member] Per Year 2030-2032 Program Cycle Redemption price, percentage Debt Instrument, Redemption Price, Percentage Total investments and other noncurrent assets Deferred Charges And Other Assets, Noncurrent Deferred Charges And Other Assets, Noncurrent Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Arrangement Duration Trading Arrangement Duration Consolidation Items [Axis] Consolidation Items [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Total revenues REVENUES Revenues Revenues United States v. Householder, et al. United States v. Householder, et al. [Member] United States v. Householder, et al. Loss Contingencies By Claims [Axis] Loss Contingencies By Claims [Axis] Loss Contingencies By Claims. Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount FE FE [Member] FE Environmental liabilities former gas facilities Environmental Liabilities Former Gas Facilities Environmental Liabilities Former Gas Facilities. Schedule of Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] All Award Types Award Type [Domain] Net assets Fair Value Of Assets (Liabilities) Net Fair value of assets and liabilities net. Debt Instrument Convertible Terms Of Conversion [Domain] Debt Instrument Convertible Terms Of Conversion [Domain] Debt Instrument Convertible Terms Of Conversion [Domain] FAIR VALUE MEASUREMENTS Fair Value Disclosures [Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] Noncontrolling interest, ownership percentage by noncontrolling owners Subsidiary, Ownership Percentage, Noncontrolling Owner Debt instrument, convertible, threshold percentage of stock price trigger Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger Geographical [Axis] Geographical [Axis] 4.00%, Convertible Notes Maturity 2026 4.00%, Convertible Notes Maturity 2026 [Member] 4.00%, Convertible Notes Maturity 2026 Proceeds from divestiture of interest in joint venture Proceeds from Divestiture of Interest in Joint Venture 2026 Convertible Notes conversion premium Conversion premium on the 2026 Convertible Notes Adjustments To Additional Paid In Capital, Convertible Debt Conversion Premium Adjustments To Additional Paid In Capital, Convertible Debt Conversion Premium Integrated Segment Integrated Integrated Segment [Member] Integrated Segment Legal Entity [Axis] Legal Entity [Axis] Regulatory liability amount to be refunded Public Utilities, Regulatory Liability, Amount to be Refunded To Customers Public Utilities, Regulatory Liability, Amount to be Refunded To Customers Equity Method Investments Equity Method Investments [Policy Text Block] Cash, cash equivalents, and restricted cash at beginning of period Cash, cash equivalents, and restricted cash at end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Path Wv Path Wv [Member] PATH-WV [Member]. Schedule of Changes to the ARO Balances Schedule of Change in Asset Retirement Obligation [Table Text Block] Non-NEOs Non-NEOs [Member] Delivery Capital Recovery Rider Delivery Capital Recovery Rider [Member] Delivery Capital Recovery Rider [Member] Plant capacity (in MW's) Plant Capacity Plant Capacity Internal revenues Internal Customers [Member] Internal Customers [Member] Equity method investment, ownership percentage Equity Method Investment, Ownership Percentage Transource Transource [Member] Transource Residential Residential Customers [Member] Residential Customers [Member] Customer [Domain] Customer [Domain] Investment, Name [Domain] Investment, Name [Domain] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Customer deposits Customer deposits Contract with Customer, Liability, Current Ohio Funding Companies Ohio Funding Companies [Member] Ohio Funding Companies [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Award Type Award Type [Axis] Convertible Notes Maturity 2029 & 2031 Convertible Notes Maturity 2029 & 2031 [Member] Convertible Notes Maturity 2029 & 2031 Public utilities, requested year two Public Utilities, Proposed Costs, Scenario Two Public Utilities, Proposed Costs, Scenario Two Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Transmission Related Vegetation Management Programs Transmission Related Vegetation Management Programs [Member] Transmission Related Vegetation Management Programs Per Year 2022 Through 2024 Per Year 2022 Through 2024 [Member] Per Year 2022 Through 2024 Retained earnings Retained earnings Retained Earnings (Accumulated Deficit) Product and Service [Axis] Product and Service [Axis] Equity securities Equity Securities, FV-NI Debt instrument, convertible, threshold trading days Debt Instrument, Convertible, Threshold Trading Days Cash payments to escrow deposit Cash Payments To Escrow Deposit For Surety Bond Cash Payments To Escrow Deposit For Surety Bond KATCo KATCo [Member] KATCo Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Pension Pension Pension Plan [Member] Common stock Common Stock Common Stock [Member] Fair Value Debt Securities, Available-for-Sale Customer Receivables Receivable [Policy Text Block] TOTAL LIABILITIES AND EQUITY Liabilities and Equity Number of billing cycles Public Utilities, Customer Restitution, Repayment Period, Number Of Billing Cycles Public Utilities, Customer Restitution, Repayment Period, Number Of Billing Cycles Debt Instrument Convertible Terms Of Conversion [Axis] Debt Instrument Convertible Terms Of Conversion [Axis] Debt Instrument Convertible Terms Of Conversion Stock Options Share-Based Payment Arrangement, Option [Member] Noncontrolling interest Equity, Attributable to Noncontrolling Interest Business Segments [Axis] Segments [Axis] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Related and Nonrelated Parties [Domain] Related and Nonrelated Parties [Domain] Tabular List, Table Tabular List [Table Text Block] Accretion Asset Retirement Obligation, Accretion Expense Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Assumed impact of the 2029 Convertible Notes and the 2031 Convertible Notes conversion premium (in shares) Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities Name Awards Close in Time to MNPI Disclosures, Individual Name Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Curing period Guarantor Obligations, Curing Period Guarantor Obligations, Curing Period PROPERTY, PLANT AND EQUIPMENT: PROPERTY, PLANT AND EQUIPMENT: Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization [Abstract] Net periodic benefit credits, net of amounts capitalized Defined Benefit Plan, Net Periodic Benefit Cost, Excluding Capitalized Amounts Defined Benefit Plan, Net Periodic Benefit Cost, Excluding Capitalized Amounts Adjustment to Compensation: Adjustment to Compensation [Axis] Debt Conversion Terms Two Debt Conversion Terms Two [Member] Debt Conversion Terms Two Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Capital investments Capital investments Payments to Acquire Productive Assets Total assets Assets, Fair Value Disclosure Long-term debt and other long-term obligations Long-term debt and other long-term obligations Long-Term Debt and Lease Obligation Name Measure Name Pay vs Performance Disclosure [Line Items] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Debt Instrument [Line Items] Debt Instrument [Line Items] OPIC Other Paid-In Capital Additional Paid-in Capital [Member] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] 4.00% Unsecured Senior Notes Maturing 2026 4.00% Unsecured Senior Notes Maturing 2026 [Member] 4.00% Unsecured Senior Notes Maturing 2026 Short-term borrowings, net Repayments of Short-Term Debt Demand reduction targets Public Utilities, Approved Demand Reduction Targets Public Utilities, Approved Demand Reduction Targets Realized losses Debt and Equity Securities, Realized Losses Debt and Equity Securities, Realized Losses Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and Cash Equivalent Other Sundry Investments Other Sundry Investments [Member] Other Sundry Investments Company Selected Measure Amount Company Selected Measure Amount Secured Overnight Financing Rate (SOFR) Secured Overnight Financing Rate (SOFR) [Member] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Accounts and Financing Receivables [Table] Non-PEO NEO Non-PEO NEO [Member] Recovery of project abandonment costs incurred thereafter (percent) Public Utilities, Recovery Of Project Abandonment, Costs Incurred Thereafter, Percentage Public Utilities, Recovery Of Project Abandonment, Costs Incurred Thereafter, Percentage Long-term pollution control bond Long-Term Pollution Control Bond Schedule of Fair Value and Related Carrying Amounts of Long-term Debt Fair Value And Related Carrying Amounts Of Long Term Debt And Other Long Term Obligations [Table Text Block] Fair value and related carrying amounts of long-term debt and other long-term obligations. Award Timing Method Award Timing Method [Text Block] Other revenue unrelated to contracts with customers Product and Service, Other [Member] Net change in cash, cash equivalents, and restricted cash Net change in cash, cash equivalents, and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Asset retirement obligation, discount rate Asset Retirement Obligation, Discount Rate Asset Retirement Obligation, Discount Rate Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] ME Metropolitan Edison Company [Member] Metropolitan Edison Company United States Treasury United States Treasury [Member] United States Treasury Public utilities, requested year three Public Utilities, Proposed Costs, Scenario Three Public Utilities, Proposed Costs, Scenario Three Changes in timing and amount of estimated cash flows Asset Retirement Obligation, Revision of Estimate EARNINGS ATTRIBUTABLE TO FIRSTENERGY CORP. Net income Earnings Attributable to FE Earnings (losses) attributable to FE/Net income Net Income (Loss) Attributable to Parent Customer restitution paid Payments For Customer Restitution Payments For Customer Restitution Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Approved ROE Public Utilities, Approved Return on Equity, Percentage Restatement Determination Date: Restatement Determination Date [Axis] Electric Companies and Transmission Companies Regulated Distribution and Regulated Transmission [Member] Regulated Distribution and Regulated Transmission [Member] Per Year 2025 Per Year 2025 And 2026 [Member] Per Year 2025 And 2026 Amount of refunds announced Litigation Settlement, Amount Awarded to Other Party Receivables - Receivables - Receivables, Net, Current [Abstract] PPUC Pennsylvania Public Utility Commission [Member] Pennsylvania Public Utility Commission [Member] Debt instrument, convertible, threshold consecutive trading days Debt Instrument, Convertible, Threshold Consecutive Trading Days Per Year 2027 Per Year 2027 [Member] Per Year 2027 Company posted collateral related to net liability positions Company Posted Collateral Related To Net Liability Positions Company Posted Collateral Related To Net Liability Positions. REVENUES: Revenues [Abstract] Other Guarantee Type, Other [Member] Integrated Integrated [Member] Integrated Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING: Weighted Average Number of Shares Outstanding, Diluted [Abstract] New Jersey NEW JERSEY Statistical Measurement [Domain] Statistical Measurement [Domain] Segment Financial Information Segment Financial Information Abstract Segment Financial Information. Document Fiscal Year Focus Document Fiscal Year Focus Interest and dividend income Investment Income From Trusts Investment Income From Trusts 4.60% Unsecured Senior Notes Maturing 2030 4.60% Unsecured Senior Notes Maturing 2030 [Member] 4.60% Unsecured Senior Notes Maturing 2030 Customer [Axis] Customer [Axis] PJM 2025 RTEP Window 1 PJM 2025 RTEP Window 1 [Member] PJM 2025 RTEP Window 1 Schedule of Long-term Debt Redemption and Issuance Schedule of Long-Term Debt Instruments [Table Text Block] Line of Credit Line of Credit [Member] Restatement Determination Date Restatement Determination Date Tax Jurisdiction of Domicile [Extensible Enumeration] Tax Jurisdiction of Domicile [Extensible Enumeration] Prepaid OPEB costs Prepaid Expense Other, Noncurrent Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets 4.15% Unsecured Senior Notes Maturity 2028 4.15% Unsecured Senior Notes Maturity 2028 [Member] 4.15% Unsecured Senior Notes Maturity 2028 OHIO OHIO Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Beginning balance Ending balance Accounts Receivable, Allowance for Credit Loss Regulatory liabilities Regulatory Liability, Noncurrent Amendment Flag Amendment Flag CURRENT LIABILITIES: CURRENT LIABILITIES: Liabilities, Current [Abstract] Provision for expected credit losses Accounts Receivable, Credit Loss Expense (Reversal) External revenues External Customers [Member] External Customers [Member] Unrealized Losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Schedule of Amortized Cost Basis, Unrealized Gains and Losses and Fair Values of Investments in Available-for-sale Securities Debt Securities, Available-for-Sale [Table Text Block] Regulatory Matters [Line Items] Regulatory Matters [Line Items] Regulatory matters. 5.19% Unsecured Senior Notes Maturing 2033 5.19% Unsecured Senior Notes Maturing 2033 [Member] 5.19% Unsecured Senior Notes Maturing 2033 Total noncurrent liabilities Liabilities, Noncurrent Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Liabilities settled Asset Retirement Obligation, Liabilities Settled Number of consecutive annual test periods Number of Consecutive Annual Test Periods Number of Consecutive Annual Test Periods Entity Address, State or Province Entity Address, State or Province REGULATORY MATTERS Public Utilities Disclosure [Text Block] PEO Total Compensation Amount PEO Total Compensation Amount Assets Assets, Fair Value Disclosure [Abstract] Capital investments Segment Reporting, Long-Lived Asset, Expenditure for Addition Public utility, offshore development, percent Public Utility, Requested Acquisition Option, Offshore Development, Percent Public Utility, Requested Acquisition Option, Offshore Development, Percent Basic (in shares) Weighted average number of basic shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Schedule of Transactions with Affiliated Companies Schedule of Related Party Transactions [Table Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Regulatory assets Regulatory assets Regulatory Asset, Noncurrent Transfer of McElroy’s Run CCR impoundment facility Transfer to Investments Federal and state related flow-through Effective Income Tax Rate Reconciliation, Federal And State Related Flow-through, Amount Effective Income Tax Rate Reconciliation, Federal And State Related Flow-through, Amount Maryland MARYLAND WP West Penn Power Company [Member] West Penn Power Company Number of transmission projects Number Of Transmission Projects Number Of Transmission Projects Total revenues from contracts with customers Revenue from Contract with Customer, Including Assessed Tax Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Defined Benefit Plan Disclosure [Line Items] Penn Pennsylvania Power Company [Member] Pennsylvania Power Company Other Electric Worldwide Unregulated Revenue [Member] Electric Worldwide Unregulated Revenue [Member] Document Information [Line Items] Document Information [Line Items] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Unsecured Senior Notes Due 2030 Unsecured Senior Notes Due 2030 [Member] Unsecured Senior Notes Due 2030 Sale proceeds Debt And Equity Securities, Realized Gain (Loss), Sales Proceeds Debt And Equity Securities, Realized Gain (Loss), Sales Proceeds Receivable [Domain] Receivable [Domain] Incremental energy savings goal thereafter (percent) Incremental Energy Savings Goal, Percent Incremental Energy Savings Goal, Percent New financing- New financing- New Financing [Abstract] New Financing Abstract. AFUDC equity income Effective Income Tax Rate Reconciliation, Allowance For Funds Used During Construction Equity Income, Percent Effective Income Tax Rate Reconciliation, Allowance For Funds Used During Construction Equity Income, Percent Earnings Per Share Earnings Per Share, Policy [Policy Text Block] New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Litigation Case [Axis] Litigation Case [Axis] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Accrued capital investments Accrued capital investments Capital Expenditures Incurred but Not yet Paid Customer Customer Customer [Member] Customer. NCI Noncontrolling Interest [Member] Unsecured Debt Unsecured Debt [Member] Long-term debt Long-Term Debt Accrued taxes Accrued taxes Increase (Decrease) in Income Taxes Payable Ohio Development Service Ohio Development Service [Member] Ohio Development Service Total Exposure from Contractual Obligations Credit Rating Contingent Contractual Obligations [Member] Credit Rating Contingent Contractual Obligations Net cash used for investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Deferral of regulatory assets, net Deferral of regulatory assets, net Deferral of regulatory assets, net Amortization (Deferral) Of Regulatory Asset, Net Amortization (Deferral) Of Regulatory Asset, Net Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] FE’s Guarantees on Other Assurances Other Assurances [Member] Other Assurances [Member] OPERATING EXPENSES: OPERATING EXPENSES: Costs and Expenses [Abstract] Security Exchange Name Security Exchange Name Excess deferred tax amortization Effective Income Tax Rate Reconciliation, Excess Deferred Tax Amortization, Amount Effective Income Tax Rate Reconciliation, Excess Deferred Tax Amortization, Amount AFUDC equity depreciation Effective Income Tax Rate Reconciliation, Allowance For Funds Used During Construction Equity Depreciation, Amount Effective Income Tax Rate Reconciliation, Allowance For Funds Used During Construction Equity Depreciation, Amount Total liabilities Liabilities, Fair Value Disclosure Accrued interest Accrued interest Interest Payable, Current Pennsylvania PENNSYLVANIA Name Outstanding Recovery, Individual Name Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Public utilities, amount awarded from other party Public Utilities, Amount Awarded From Other Party Public Utilities, Amount Awarded From Other Party Agreed funding period Asset Retirement Obligation, Agreed Funding Period Asset Retirement Obligation, Agreed Funding Period Geographical [Domain] Geographical [Domain] Public utilities, revenue impact of sales losses to be recovered Public Utilities, Revenue Impact of Sales Losses to be Recovered Public Utilities, Revenue Impact of Sales Losses to be Recovered Public utilities, capital commitments Public Utilities, Capital Commitments Public Utilities, Capital Commitments Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Number of subsidiaries that issued environmental control bonds Number Of Subsidiaries That Issued Environmental Control Bonds Number Of Subsidiaries That Issued Environmental Control Bonds Purchased power Purchased power Utilities Operating Expense, Purchased Power Approved amount of annual increase Approved amount of annual increase (decrease) Public Utilities, Approved Rate Increase (Decrease), Amount Debt Conversion Terms One Debt Conversion Terms One [Member] Debt Conversion Terms One Commercial Commercial Customers [Member] Commercial Customers [Member] Share count information: Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract] Employee benefit costs, net Employee benefit costs, net Pension and Other Postretirement Benefits Cost (Reversal of Cost) Ownership percentage by parent Subsidiary, Ownership Percentage, Parent 3.625%, Convertible Notes Maturity 2029 3.625%, Convertible Notes Maturity 2029 [Member] 3.625%, Convertible Notes Maturity 2029 Debt securities Debt Securities [Member] Related Party Transactions [Abstract] MP and PE Monogahela Power Company and The Potomac Edison Company [Member] Monogahela Power Company and The Potomac Edison Company [Member] Guarantee Type [Axis] Guaranteed Insurance Contract, Type of Guarantee [Axis] Distribution Distribution Segment Regulated Distribution [Member] Regulated Distribution. Long-Term Debt and Other Long-Term Obligations Debt, Policy [Policy Text Block] Compensation Amount Outstanding Recovery Compensation Amount Annual revenue cap for DCR rider Public Utilities, Annual Revenue Cap For Rider Annual Revenue Cap For DCR Rider Individual: Individual [Axis] Diluted (in shares) Weighted average number of diluted shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Entity Emerging Growth Company Entity Emerging Growth Company Related Party Transaction [Line Items] Related Party Transaction [Line Items] Retirement benefits Retirement benefits Liability, Defined Benefit Plan, Noncurrent Underlying Security Market Price Change Underlying Security Market Price Change, Percent Asset removal costs Asset removal costs Payments for Removal Costs DMR Revenues DMR Revenues [Member] DMR Revenues Short-term borrowings Short-Term Debt Public utilities, GHG reduction targets Public Utilities, Revised Requested Rate, Amount Public Utilities, Revised Requested Rate, Amount Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Common stock, shares issued not disclosed Common Stock Shares Issued Not Disclosed Common Stock Shares Issued Not Disclosed Restricted cash Restricted Cash, Current Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-Sale [Line Items] West Virginia WEST VIRGINIA Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Upon downgrade Upon Further Downgrade [Member] Upon Further Downgrade [Member] All Executive Categories All Executive Categories [Member] Cash, cash equivalents and restricted cash Cash, Cash Equivalents And Restricted Cash, Fair Value Disclosure Cash, Cash Equivalents And Restricted Cash, Fair Value Disclosure Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Initial threshold rate Debt Instrument, Covenant, Threshold Rate Debt Instrument, Covenant, Threshold Rate Schedule of Components of Net Periodic Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Depreciation and amortization Depreciation and amortization Depreciation, Depletion, Amortization And Impairments Depreciation, Depletion, Amortization And Impairments Collateral received Cash Collateral Received For Supply Contracts, Net Cash Collateral Received For Supply Contracts, Net Schedule of Reconciles Basic and Diluted Eps Attributable to FE Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Nuclear fuel disposal costs Spent Nuclear Fuel Obligation, Noncurrent SEGMENT INFORMATION Segment Reporting [Text Block] Minimum Minimum [Member] Stand-Alone Transmission Stand-Alone Transmission Segment [Member] Stand-Alone Transmission Segment Notes Maturity 2029 & 2031 Notes Maturity 2029 & 2031 [Member] Notes Maturity 2029 & 2031 Schedule of Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] VARIABLE INTEREST ENTITIES Variable Interest Entity Disclosure [Text Block] Income Statement Location [Axis] Location, Statement of Income, Balance [Axis] Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Schedule of Proceeds from the Sale of Investments in Available-for-sale Debt Securities Proceeds From Sale Of Investments In Available For Sale Securities Realized Gains And Losses On Those Sales And Interest And Dividend Income [Table Text Block] Proceeds from sale of investments in available-for-sale securities, realized gains and losses on those sales, and interest and dividend income. Public Utilities, Regulatory Proceeding [Domain] Public Utilities, Regulatory Proceeding [Domain] Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Amount of requested increase Amount of requested increase (decrease) Public Utilities, Requested Rate Increase (Decrease), Amount Net periodic benefit costs (credits) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Spent nuclear fuel disposal trust income Spent Nuclear Fuel Disposal Trust Income (Loss) Spent Nuclear Fuel Disposal Trust Income (Loss) Common stock, authorized (in shares) Common Stock, Shares Authorized Proposed goal to reduce CO2 pollution (percent) Proposed Action, Reduction In Power Plants Carbon Pollution, Percentage Proposed Action, Reduction In Power Plants Carbon Pollution, Percentage Asset Retirement Obligation Disclosure [Abstract] Accrued compensation and benefits Accrued compensation and benefits Accrued Employee Benefits, Current Exercise Price Award Exercise Price Recurring Fair Value, Recurring [Member] MAIT Mid-Atlantic Interstate Transmission, LLC [Member] Mid-Atlantic Interstate Transmission, LLC [Member] Segment Reporting [Line Items] Segment Reporting [Line Items] EE&C Phase IV Energy Efficiency and Conservation Phase IV [Member] Energy Efficiency and Conservation Phase IV Document Quarterly Report Document Quarterly Report Public utilities, increase in total revenues, percentage Public Utilities, Increase in Total Revenues, Percentage Public Utilities, Increase in Total Revenues, Percentage Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Energy consumption reduction targets Public Utilities, Approved Energy Consumption Reduction Targets Public Utilities, Approved Energy Consumption Reduction Targets Sales of investment securities held in trusts Sales of investment securities held in trusts Proceeds from Sale of Debt Securities, Available-for-Sale Accrued and unpaid interest Interest Payable Long-term debt Repayments of debt Repayments of Long-Term Debt Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Equity method investments Equity Method Investments Equity Component [Domain] Equity Component [Domain] Customers Customers Accounts Receivable, before Allowance for Credit Loss, Current Adoption Date Trading Arrangement Adoption Date Counterparty Name [Domain] Counterparty Name [Domain] Variable Interest Entities [Abstract] Variable Interest Entities [Abstract] Variable Interest Entities Abstract. Total other expense Nonoperating Income (Expense) JCP&L JERSEY CENTRAL POWER & LIGHT COMPANY [Member] JERSEY CENTRAL POWER & LIGHT COMPANY Regulatory Agency [Axis] Regulatory Agency [Axis] Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Debt securities Debt Securities, Held-to-Maturity, Fair Value Regulatory Agency [Domain] Regulatory Agency [Domain] Debt issuance and redemption costs, and other Debt issuance costs and other Proceeds from (Payment for) Other Financing Activity Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Phase In Recovery Bonds Phase In Recovery Bonds [Member] Phase In Recovery Bonds [Member] Transmission investment plan period Public Utilities, Transmission Investment Plan Period Public Utilities, Transmission Investment Plan Period Schedule of Error Corrections and Prior Period Adjustments Schedule of Error Corrections and Prior Period Adjustments [Table Text Block] Transmission Electric Transmission [Member] Threshold trading days measurement period Debt Instrument, Convertible, Threshold Trading Days, Measurement Period Debt Instrument, Convertible, Threshold Trading Days, Measurement Period Maximum aggregate amount of securities registered Maximum Aggregate Amount Of Securities Registered Maximum Aggregate Amount Of Securities Registered Letter of Credit LOCs Letter of Credit [Member] COMMITMENTS, GUARANTEES AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Regulated Transmission Stand-Alone Transmission Regulated Transmission [Member] Regulated Transmission [Member] Operating expenses capitalized Utilities Operating Expense, Maintenance, Operations, Costs Capitalized Utilities Operating Expense, Maintenance, Operations, Costs Capitalized Weighted Average Weighted Average [Member] Common stock, $0.10 par value, authorized 700,000,000 shares - 578,639,932 and 577,851,052 shares outstanding as of June 30, 2026, and December 31, 2025, respectively. Common stock, $10 par value, authorized 16,000,000 shares - 13,628,447 shares outstanding as of June 30, 2026, and December 31, 2025. Common Stock, Value, Outstanding All Adjustments to Compensation All Adjustments to Compensation [Member] Corporate/ Other Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] Other Other Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Other Item Net cash provided from operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation MP, PE and the Ohio Companies MP, PE and the Ohio Companies [Member] MP, PE and the Ohio Companies Common stockholders’ equity- COMMON STOCKHOLDER'S EQUITY: Equity, Attributable to Parent [Abstract] Income Statement [Abstract] Income Statement [Abstract] Document Transition Report Document Transition Report Requested Approach Effective August 1, 2026 Requested Approach Effective August 1, 2026 [Member] Requested Approach Effective August 1, 2026 Gain on Investments Gain (Loss) on Investments FMB First Mortgage Bond [Member] First Mortgage Bond Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] City Area Code City Area Code Document Information [Table] Document Information [Table] Name Forgone Recovery, Individual Name Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Public utilities, near-term market capacity purchases (in MV's) Public Utilities, Addition To Capacity Amounts Public Utilities, Addition To Capacity Amounts Three-Year Rate Plan, Revenue Increases in Year One Three-Year Rate Plan, Revenue Increases in Year One [Member] Three-Year Rate Plan, Revenue Increases in Year One Sale of ownership interest by parent Consolidation, Less Than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Sale Of Interest by Parent, Percent Consolidation, Less Than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Sale Of Interest by Parent, Percent Entity [Domain] Entity [Domain] Accrual for environmental loss contingencies Accrual for Environmental Loss Contingencies Effective Income Tax Rate Reconciliation [Line Items] Effective Income Tax Rate Reconciliation [Line Items] Deferred refunded to customer Allowance For Loan And Loss, Deferred Recovery Of Bad Debts Allowance For Loan And Loss, Deferred Recovery Of Bad Debts 5.15% Unsecured Senior Notes Maturity 2026 5.15% Unsecured Senior Notes Maturity 2026 [Member] 5.15% Unsecured Senior Notes Maturity 2026 2026 Convertible Notes 2026 Convertible Notes [Member] 2026 Convertible Notes Utilities, transmission owning utilities join an RTO Utilities, Transmission Owning Utilities Join An RTO Utilities, Transmission Owning Utilities Join An RTO Unsecured Senior Notes Due 2031 Unsecured Senior Notes Due 2031 [Member] Unsecured Senior Notes Due 2031 Tax related to FE's equity investment in FET Effective Income Tax Rate Reconciliation, Equity in Earnings (Losses) of Unconsolidated Subsidiary, Amount MP MP [Member] MP Measurement Basis [Axis] Measurement Basis [Axis] Federal and state related flow-through Effective Income Tax Rate Reconciliation, Federal And State Related Flow-through, Percent Effective Income Tax Rate Reconciliation, Federal And State Related Flow-through, Percent Subsequent Event Type [Domain] Subsequent Event Type [Domain] Revision of Prior Period [Domain] Revision of Prior Period [Domain] ASSET RETIREMENT OBLIGATIONS Asset Retirement Obligation Disclosure [Text Block] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Entity Current Reporting Status Entity Current Reporting Status Net cash provided from financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Term Loan Credit Agreement Term Loan Credit Agreement [Member] Term Loan Credit Agreement Total Shareholder Return Amount Total Shareholder Return Amount Liabilities Liabilities, Fair Value Disclosure [Abstract] Corporate/Other and Reconciling Adjustments Corporate And Reconciling Items [Member] Corporate And Reconciling Items Adjustments to reconcile net income to net cash from operating activities- Adjustments to reconcile net income to net cash from operating activities- Adjustments to reconcile net income to net cash from operating activities- Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Write-offs Accounts Receivable, Allowance for Credit Loss, Writeoff Approved temporary electric rate Public Utilities, Approved Temporary Electric Rate Credit Per Monthly Bill Public Utilities, Approved Temporary Electric Rate Credit Per Monthly Bill Interest costs Defined Benefit Plan, Interest Cost Regulatory Asset [Line Items] Regulatory Asset [Line Items] Financial Instruments [Domain] Financial Instruments [Domain] Recognition period Asset Retirement Obligation, Recognition Period Asset Retirement Obligation, Recognition Period Number of completed solar sites Public Utilities, Number of Completed Solar Sites Public Utilities, Number of Completed Solar Sites Derivative assets FTRs Derivative Asset Underlying Securities Award Underlying Securities Amount Fair value Estimate of Fair Value Measurement [Member] REVENUE Revenue from Contract with Customer [Text Block] Natural Gas Generation Project Natural Gas Generation Project [Member] Natural Gas Generation Project AFUDC equity depreciation Effective Income Tax Rate Reconciliation, Allowance For Funds Used During Construction Equity Depreciation, Percent Effective Income Tax Rate Reconciliation, Allowance For Funds Used During Construction Equity Depreciation, Percent Other Other Payment for (Proceeds from) Other Investing Activity Materials and supplies Increase (Decrease) in Inventories Customer restitution Public Utilities, Customer Restitution, Total Public Utilities, Customer Restitution, Total PE PE [Member] PE. Segment Reporting [Table] Segment Reporting [Table] 4.45%, $300 Million Notes Maturity 2029 4.45%, $300 Million Notes Maturity 2029 [Member] 4.45%, $300 Million Notes Maturity 2029 Related Party Transaction [Table] Related Party Transaction [Table] CASH FLOWS FROM INVESTING ACTIVITIES: CASH FLOWS FROM INVESTING ACTIVITIES: Cash Provided by (Used in) Investing Activity, Continuing Operation [Abstract] Prepaid taxes and other Other Assets, Current Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Distribution services and retail generation Electricity, US Regulated [Member] Current Fiscal Year End Date Current Fiscal Year End Date ATSI ATSI [Member] ATSI. Other Other Receivables [Member] Other receivables. Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Regulatory Matters [Table] Regulatory Matters [Table] Regulatory matters. Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Dividends declared (in dollars per share) Common Stock, Dividends, Per Share, Declared Entity File Number Entity File Number Expected future contributions Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Noncontrolling interest cash distributions declared Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Measure: Measure [Axis] Number of scenarios with projected costs submitted for cost recovery program Number Of Scenarios With Projected Costs Submitted For Cost Recovery Program Number Of Scenarios With Projected Costs Submitted For Cost Recovery Program Equity Components [Axis] Equity Components [Axis] Other operating expenses Other operating expenses Other Cost and Expense, Operating Related Party Related Party [Member] Dominion HV Dominion HV [Member] Dominion HV Utilities, transmission owing utilities join an RTO Utilities, Basis Point Adder Associated With RTO Membership Utilities, Basis Point Adder Associated With RTO Membership Entity Interactive Data Current Entity Interactive Data Current Variable Rate [Axis] Variable Rate [Axis] Income attributable to noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest Wholesale Wholesale Sales [Member] Wholesale Sales [Member] Entity Small Business Entity Small Business In service In service Public Utilities, Property, Plant and Equipment, Plant in Service COMPREHENSIVE INCOME ATTRIBUTABLE TO FIRSTENERGY CORP. COMPREHENSIVE INCOME Comprehensive Income (Loss), Net of Tax, Attributable to Parent Utility Plant [Domain] Utility Plant [Domain] Three-Year Rate Plan, Revenue Increases in Year Three Three-Year Rate Plan, Revenue Increases in Year Three [Member] Three-Year Rate Plan, Revenue Increases in Year Three Effective Income Tax Rate Reconciliation [Table] Effective Income Tax Rate Reconciliation [Table] Accounts payable Accounts payable Increase (Decrease) in Accounts Payable, Trade Excise taxes collected Excise Taxes Collected MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Asset Retirement Obligation [Table] Asset Retirement Obligation [Table] Asset Retirement Obligation The Ohio Companies CEI, OE and TE [Member] CEI, OE and TE [Member] Other Other Other Assets, Noncurrent PJM PJM Interconnection, LLC [Member] PJM Interconnection, LLC CASH FLOWS FROM FINANCING ACTIVITIES: CASH FLOWS FROM FINANCING ACTIVITIES: Cash Provided by (Used in) Financing Activity, Continuing Operation [Abstract] Document Type Document Type Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Decrease in asset retirement obligation Asset Retirement Obligation, Period Increase (Decrease) Debt redemption costs (Note 6..) Gain (Loss) on Extinguishment of Debt Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Long-term debt Debt issuances Proceeds from Issuance of Long-Term Debt Local Phone Number Local Phone Number OPEB Other Postretirement Benefits Plan [Member] Customer restitution, after tax Public Utilities, Customer Restitution, After Tax, Total Public Utilities, Customer Restitution, After Tax, Total Requested capital structure, debt, percentage Public Utilities, Requested Debt Capital Structure, Percentage Changes in current assets and liabilities- Changes in current assets and liabilities- Increase (Decrease) in Operating Assets [Abstract] Capital structure, equity Public Utilities, Approved Equity Capital Structure, Percentage INCOME BEFORE INCOME TAXES Income before income taxes Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest COMMITMENTS, GUARANTEES AND CONTINGENCIES (NOTE 10.) COMMITMENTS, GUARANTEES AND CONTINGENCIES (NOTE 10.) Commitments and Contingencies Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Accounting Standards Update and Change in Accounting Principle [Table] Accounting Standards Update and Change in Accounting Principle [Table] Executive Category: Executive Category [Axis] Regulation of Waste Disposal Regulation Of Waste Disposal [Member] Regulation Of Waste Disposal. Receivable Type [Axis] Receivable Type [Axis] Counterparty Name [Axis] Counterparty Name [Axis] Property, plant and equipment in service net of accumulated provision for depreciation Net Plant Excluding Construction Work In Progress Amount, net of accumulated depreciation of long-lived physical assets, excluding construction in progress, used in the normal conduct of business and not intended for resale. 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Fair Value Measurement [Domain] Fair Value Measurement [Domain] Minimum consolidated interest coverage ratio (not less than) Debt Instrument, Covenant, Interest Coverage Ratio, Minimum Debt Instrument, Covenant, Interest Coverage Ratio, Minimum Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Cover [Abstract] Equity Awards Adjustments Equity Awards Adjustments [Member] Plant capacity (in MW's) Public Utilities, Plant Construction, Capacity of Plants Public Utilities, Plant Construction, Capacity of Plants Excess deferred tax amortization Effective Income Tax Rate Reconciliation, Excess Deferred Tax Amortization, Percent Effective Income Tax Rate Reconciliation, Excess Deferred Tax Amortization, Percent Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Senior Unsecured Notes Payable, Other Payables [Member] Construction work in progress Construction work in progress Public Utilities, Property, Plant and Equipment, Construction Work in Progress Schedule of Receivables from Customers Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Loss in period Loss Contingency Accrual, Loss (Reversal of Loss) Miscellaneous income, net Miscellaneous income, net Other Nonoperating Income (Expense) Total Common Stockholders’ Equity Parent [Member] Investments not required to be disclosed Investments not required to be disclosed Investments not required to be disclosed. New Jersey temporary rate credits, net New Jersey Temporary Rate Collections, Net New Jersey Temporary Rate Collections, Net Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Number of regional transmission centers Number Of Regional Transmission Centers Number Of Regional Transmission Centers INVESTMENTS AND OTHER NONCURRENT ASSETS: INVESTMENTS AND OTHER NONCURRENT ASSETS: Deferred Charges And Other Assets [Abstract] Deferred Charges And Other Assets Abstract. 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