Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] 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 Subsequent Event Subsequent Event [Member] Carrying value Reported Value Measurement [Member] Document Fiscal Year Focus Document Fiscal Year Focus 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 Adjustment to Compensation, Amount Adjustment to Compensation Amount Customer [Axis] Customer [Axis] Schedule of Long-term Debt Redemption and Issuance Schedule of Long-Term Debt Instruments [Table Text Block] State and municipal income taxes, net of federal effect Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Total Guarantees and Other Assurances Maximum potential amount of future payments Guarantor Obligations, Maximum Exposure, Undiscounted Restatement Determination Date Restatement Determination Date Tax Jurisdiction of Domicile [Extensible Enumeration] Tax Jurisdiction of Domicile [Extensible Enumeration] Number of transmission projects Number Of Transmission Projects Number Of Transmission Projects Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Corporate AMT credit carryforwards Deferred Tax Assets, Corporate AMT Credit Carryforwards Deferred Tax Assets, Corporate AMT Credit Carryforwards Loans with affiliated companies, net Payments for (Proceeds from) Loans Receivable Regulatory liabilities Regulatory Liability, Noncurrent Amendment Flag Amendment Flag Consolidated Entities [Axis] Consolidated Entities [Axis] CURRENT LIABILITIES: Liabilities, Current [Abstract] Entity Common Stock Shares Outstanding Entity Common Stock, Shares Outstanding Other affiliate support services Other Affiliate Support Services [Member] Other Affiliate Support Services Capitalized cost of equity Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity Percent Effective Income Tax Rate Reconciliation, Percent [Abstract] Goodwill Goodwill and Intangible Assets, Policy [Policy Text Block] Number of additional renewal options Lessee, Operating Lease, Number Of Additional Renewal Options Lessee, Operating Lease, Number Of Additional Renewal Options Total investments and other noncurrent assets Deferred Charges And Other Assets, Noncurrent Deferred Charges And Other Assets, Noncurrent Liabilities, Noncurrent, Total Liabilities, Noncurrent TRANSACTIONS WITH AFFILIATED COMPANIES Related Party Transactions Disclosure [Text Block] Consolidated Entities [Domain] Consolidated Entities [Domain] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] 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 Maximum capped percentage of face amount of debt Guarantor Obligations, Maximum Contractual Obligations, Capped Percentage of Face Amount of Debt Guarantor Obligations, Maximum Contractual Obligations, Capped Percentage of Face Amount of Debt NONCURRENT LIABILITIES: Liabilities, Noncurrent [Abstract] Estimated refund obligation Public Utilities, Estimated Refund Obligation Public Utilities, Estimated Refund Obligation Schedule of Transactions with Affiliated Companies Schedule of Related Party Transactions [Table Text Block] Investments Long-Term Investments Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Variable Interest Entities [Abstract] Variable Interest Entities [Abstract] Variable Interest Entities Abstract. Liabilities, Current, Total Liabilities, Current Service area Service Area Service Area. TOTAL EQUITY Beginning balance Ending balance Limited Liability Company (LLC) Members' Equity, Including Portion Attributable to Noncontrolling Interest Total Revenue from Contracts with Customers Revenue from Contract with Customer, Including Assessed Tax Entity Address, City or Town Entity Address, City or Town 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 Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Special purpose membership interest held, percentage of distributions Special Purpose Membership Interest Held, Percentage Of Distributions Special Purpose Membership Interest Held, Percentage Of Distributions Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Class of Stock [Axis] Class of Stock [Axis] Basis of Accounting Basis of Accounting, Policy [Policy Text Block] Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Interest income from affiliates Interest income Investment Income, Nonoperating Tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Percent Remeasurement of excess deferred income taxes Effective Income Tax Rate Reconciliation, Remeasurement Of Excess Deferred Income Taxes, Percent Effective Income Tax Rate Reconciliation, Remeasurement Of Excess Deferred Income Taxes, Percent Subsequent Event Type [Axis] Subsequent Event Type [Axis] Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Nominal voltage (in kV) Transmission Line, Nominal Voltage 2 Transmission Line, Nominal Voltage 2 Nominal voltage (in kV) Transmission Line, Nominal Voltage 1 Transmission Line, Nominal Voltage 1 Nominal voltage (in kV) Transmission Line, Nominal Voltage 4 Transmission Line, Nominal Voltage 4 Nominal voltage (in kV) Transmission Line, Nominal Voltage 3 Transmission Line, Nominal Voltage 3 Nominal voltage (in kV) Transmission Line, Nominal Voltage 6 Transmission Line, Nominal Voltage 6 Nominal voltage (in kV) Transmission Line, Nominal Voltage 5 Transmission Line, Nominal Voltage 5 New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Nominal voltage (in kV) Transmission Line, Nominal Voltage 7 Transmission Line, Nominal Voltage 7 Accrued capital investments Capital Expenditures Incurred but Not yet Paid Noncontrolling Interest Noncontrolling Interest [Member] Use of Estimates Use of Estimates, Policy [Policy Text Block] Unsecured Debt Unsecured Debt [Member] 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 Related Party [Axis] Related and Nonrelated Parties [Axis] Long-term debt and other long-term obligations Long-Term Debt Members' Equity Member Units [Member] Guarantor Obligations [Line Items] Guarantor Obligations [Line Items] Significant non-cash transactions: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Accrued taxes Increase (Decrease) in Income Taxes Payable Document Period End Date Document Period End Date Path WV Path Wv [Member] PATH-WV [Member]. Brookfield Brookfield [Member] Brookfield Net cash used for investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] OPERATING EXPENSES: Costs and Expenses [Abstract] Common Class B Common Class B [Member] Entity Shell Company Entity Shell Company Accrued interest Interest Payable, Current Segment Information Segment Reporting, Policy [Policy Text Block] Name Outstanding Recovery, Individual Name Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Document Fiscal Period Focus Document Fiscal Period Focus Grid Growth Grid Growth [Member] Grid Growth Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] TOTAL LIABILITIES Liabilities Liabilities 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] Senior Unsecured Notes Maturing 2036 At 5.02% Senior Unsecured Notes Maturing 2036 At 5.02% [Member] Senior Unsecured Notes Maturing 2036 At 5.02% Accrued taxes Accrued Income Taxes, Current Company Selected Measure Name Company Selected Measure Name Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Property, Plant and Equipment [Table] Regulated Operation, Regulatory Asset [Table] Curing period Guarantor Obligations, Curing Period Guarantor Obligations, Curing Period Ownership percentage by parent Subsidiary, Ownership Percentage, Parent PJM 2024 RTEP Window 1 PJM 2024 RTEP Window 1 [Member] PJM 2024 RTEP Window 1 Changes in unrecognized tax benefits Effective Income Tax Rate Reconciliation, Tax Contingency, Percent Related Party Transactions [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Dominion HV Dominion HV [Member] Dominion HV 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 Long-Term Debt and Other Long-Term Obligations Debt, Policy [Policy Text Block] Compensation Amount Outstanding Recovery Compensation Amount Individual: Individual [Axis] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Entity Emerging Growth Company Entity Emerging Growth Company Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Deferred income taxes and investment tax credits, net Deferred Income Taxes and Tax Credits Grid Growth Formula Transmission Rate Grid Growth Formula Transmission Rate [Member] Grid Growth Formula Transmission Rate Asset removal costs Payments for Removal Costs Short-term borrowings- Short-Term Debt Operating expenses capitalized Utilities Operating Expense, Maintenance, Operations, Costs Capitalized Utilities Operating Expense, Maintenance, Operations, Costs Capitalized Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Transmission ROE Incentive Transmission ROE Incentive [Member] Transmission ROE Incentive 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] Tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Amount Total income taxes (benefits) Effective Income Tax Rate Reconciliation, Percent Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] All Executive Categories All Executive Categories [Member] Regulated Operations [Abstract] Regulated Operations [Abstract] Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Provision for depreciation Depreciation North American Transmission Company II LLC North American Transmission Company II LLC [Member] North American Transmission Company II LLC Operating lease right-of-use asset Operating Lease, Right-of-Use Asset Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Renewal term of lease yet to be commenced Lessee, Operating Lease, Renewal Term Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Currently payable long-term debt Long-Term Debt and Lease Obligation, Current Expiration Date Trading Arrangement Expiration Date Transmission Related Vegetation Management Programs Transmission Related Vegetation Management Programs [Member] Transmission Related Vegetation Management Programs 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] 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] Notes receivable from affiliated companies Financing Receivable, Accrued Interest, after Allowance for Credit Loss Non-affiliates Nonrelated Party [Member] Affiliated companies Affiliated Entity [Member] Defined benefit plan, plan assets, other pension and OPEB net periodic costs (credits) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Receivables Increase (Decrease) in Accounts and Other Receivables Exercise Price Award Exercise Price CASH FLOWS FROM INVESTING ACTIVITIES: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Related Party Transaction [Axis] Related Party Transaction [Axis] Valley Link Transmission Rate Valley Link Transmission Rate [Member] Valley Link Transmission Rate Document Quarterly Report Document Quarterly Report 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] Excess deferred tax amortization Effective Income Tax Rate Reconciliation, Excess Deferred Tax Amortization, Percent Effective Income Tax Rate Reconciliation, Excess Deferred Tax Amortization, Percent Long-term debt Redemptions Repayments of Long-Term Debt Basis point adder associated with RTO membership Utilities, Basis Point Adder Associated With RTO Membership Utilities, Basis Point Adder Associated With RTO Membership Property taxes Property Taxes Payable, Noncurrent Property Taxes Payable, Noncurrent Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Interest expense Interest Costs Incurred Equity Component [Domain] Equity Component [Domain] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Company posted collateral related to net liability positions Company Posted Collateral Related To Net Liability Positions Company Posted Collateral Related To Net Liability Positions. Total operating expenses Costs and Expenses Adoption Date Trading Arrangement Adoption Date Interest Rate Debt Instrument, Interest Rate, Stated Percentage PJM Interconnection, LLC PJM Interconnection, LLC [Member] PJM Interconnection, LLC Counterparty Name [Domain] Counterparty Name [Domain] Cash distribution declared Dividends, Common Stock, Cash Total other expense Nonoperating Income (Expense) 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 ASSETS Assets [Abstract] 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] Insider Trading Policies and Procedures [Line Items] Regulatory Agency [Domain] Regulatory Agency [Domain] Other Proceeds from (Payment for) Other Financing Activity Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Ground lease expense Ground Lease Expense [Member] Ground Lease Expense Revenues from affiliates Electric Transmission [Member] 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. 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] Number of operating segments Number of Operating Segments Entity Central Index Key Entity Central Index Key All Adjustments to Compensation All Adjustments to Compensation [Member] FERC Federal Energy Regulatory Commission [Member] Federal Energy Regulatory Commission Other Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Other Item 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] Net cash provided from operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Federal statutory income tax Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount MEMBERS' EQUITY: Equity, Attributable to Parent [Abstract] Income Statement [Abstract] Income Statement [Abstract] Document Transition Report Document Transition Report Ownership [Axis] Ownership [Axis] Investment, Name [Axis] Investment, Name [Axis] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Amount Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract] MAIT MAIT [Member] MAIT Capitalized financing costs Interest Costs Capitalized Adjustment City Area Code City Area Code Additional successive term Lessee, Operating Lease, Renewal Term, Additional Successive Term Lessee, Operating Lease, Renewal Term, Additional Successive Term Transource Energy, LLC Transource Energy, LLC [Member] Transource Energy, LLC Regulatory Matters [Line Items] Regulatory Matters [Line Items] Regulatory matters. MAIT Mid-Atlantic Interstate Transmission, LLC (MAIT) [Member] Mid-Atlantic Interstate Transmission, LLC (MAIT) All Individuals All Individuals [Member] FESC support services FESC Support Services [Member] FESC Support Services Distribution payments Payments of Dividends Name Forgone Recovery, Individual Name Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Statement [Line Items] Statement [Line Items] TOTAL ASSETS Assets Assets Entity [Domain] Entity [Domain] Variable Interest Entity, Not Primary Beneficiary Variable Interest Entity, Not Primary Beneficiary [Member] Interest expense Interest Expense, Nonoperating Transmission solutions to the reliability issues Public Utilities, Transmission Solutions To The Reliability Issues, Amount Public Utilities, Transmission Solutions To The Reliability Issues, Amount PEO PEO [Member] Number of additional successive periods Lessee, Operating Lease, Number Of Renewal Options Lessee, Operating Lease, Number Of Renewal Options Measurement Basis [Axis] Measurement Basis [Axis] Other Other noncurrent liabilities Other Liabilities, Noncurrent Goodwill Goodwill Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Changes in unrecognized tax benefits Effective Income Tax Rate Reconciliation, Tax Contingency, Amount Subsequent Event Type [Domain] Subsequent Event Type [Domain] Retained Earnings Retained Earnings [Member] Noncurrent operating lease obligation Operating Lease, Liability, Noncurrent Allowance for equity funds used during construction Public Utilities, Allowance for Funds Used During Construction, Additions Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Award Timing Disclosures [Line Items] Entity Current Reporting Status Entity Current Reporting Status Net cash provided from financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Sale of ownership interest by parent Equity Method Investment, Ownership Percentage, Acquired Equity Method Investment, Ownership Percentage, Acquired FET FET [Member] FET Prepaid taxes and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Capitalized interest Interest Costs Capitalized Limited refund period Public Utilities, Limited Refund Period Public Utilities, Limited Refund Period Ownership [Domain] Ownership [Domain] 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] CASH FLOWS FROM FINANCING ACTIVITIES: Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Regulatory Asset [Line Items] Regulatory Asset [Line Items] Ownership interest Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest Surety bonds Surety Bond [Member] MAIT Mid-Atlantic Interstate Transmission, LLC [Member] Mid-Atlantic Interstate Transmission, LLC [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Underlying Securities Award Underlying Securities Amount Excess deferred tax amortization Effective Income Tax Rate Reconciliation, Excess Deferred Tax Amortization, Amount Effective Income Tax Rate Reconciliation, Excess Deferred Tax Amortization, Amount Fair value Estimate of Fair Value Measurement [Member] REVENUE Revenue from Contract with Customer [Text Block] Accrued interest Increase (Decrease) in Interest Payable, Net Other current liabilities Increase (Decrease) in Other Current Liabilities Other Payment for (Proceeds from) Other Investing Activity State and municipal income taxes, net of federal effect Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Related Party Transaction [Table] Related Party Transaction [Table] AFUDC equity income Effective Income Tax Rate Reconciliation, Allowance For Funds Used During Construction Equity Income, Amount Effective Income Tax Rate Reconciliation, Allowance For Funds Used During Construction Equity Income, Amount Prepaid taxes and other Prepaid taxes and other current assets Other Assets, Current Capital structure, percentage Public Utilities, Approved Debt Capital Structure, Percentage Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] OTHER INCOME (EXPENSE): Other Nonoperating Income (Expense) [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] OPERATING INCOME Operating Income (Loss) Service Service [Member] Current Fiscal Year End Date Current Fiscal Year End Date Total members' equity Members' Equity Gain on PATH-WV liquidation (Note 1.) Gain (Loss) on Disposition of Business Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Related Party Transaction [Domain] Related Party Transaction [Domain] New financing- New Financing [Abstract] New Financing Abstract. 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] Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Pre-tax charge with interest recorded Public Utilities, Amount Awarded From Other Party Public Utilities, Amount Awarded From Other Party Measure: Measure [Axis] Schedule of Potential Amount of Future Payments Schedule of Guarantor Obligations [Table Text Block] Equity Components [Axis] Equity Components [Axis] Other operating expenses Other operating expenses: Other Cost and Expense, Operating Product and Service [Domain] Product and Service [Domain] Affiliates Related Party [Member] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Common Class A Common Class A [Member] Capitalization, Long-Term Debt and Equity [Abstract] Capitalization, Long-Term Debt and Equity [Abstract] Entity Interactive Data Current Entity Interactive Data Current Income attributable to noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest ATSI ATSI [Member] ATSI. Accumulated deferred income taxes Deferred Income Tax Liabilities, Net Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Entity Small Business Entity Small Business In service Public Utilities, Property, Plant and Equipment, Plant in Service Termination Date Trading Arrangement Termination Date Accounts payable Increase (Decrease) in Accounts Payable, Trade 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] Transmission revenue collections, net Transmission Revenue Collection, Net Transmission Revenue Collection, Net MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Other Other current liabilities Other Liabilities, Current Other Other noncurrent assets Other Assets, Noncurrent Document Type Document Type Fair Value as of Grant Date Award Grant Date Fair Value Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Arrangement Duration Trading Arrangement Duration Transource Transource [Member] Transource Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Number of directors Number Of Directors Number Of Directors Long-term debt Issuances Proceeds from Issuance of Long-Term Debt Local Phone Number Local Phone Number 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 Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Capital structure, percentage Public Utilities, Requested Debt Capital Structure, Percentage Changes in current assets and liabilities- Increase (Decrease) in Operating Assets [Abstract] Equity ratio, percentage Public Utilities, Approved Equity Capital Structure, Percentage INCOME BEFORE INCOME TAXES (BENEFITS) Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Amortization of regulatory assets, net Amortization (Deferral) Of Regulatory Asset, Net Amortization (Deferral) Of Regulatory Asset, Net Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] COMMITMENTS, GUARANTEES AND CONTINGENCIES (NOTE 7.) Commitments and Contingencies Total revenues Total revenues Revenues Revenues Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Counterparty Name [Axis] Counterparty Name [Axis] LIABILITIES AND EQUITY Liabilities and Equity [Abstract] All Award Types Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount FAIR VALUE MEASUREMENTS Fair Value Disclosures [Text Block] SUPPLEMENTAL CASH FLOW INFORMATION: Supplemental Cash Flow Information [Abstract] Property taxes Property Taxes Receivable, Noncurrent Property Taxes, NonCurrent Assets PEO Name PEO Name PATH-WV liquidation distribution (Note 1.) Proceeds from divestiture of interest in joint venture Proceeds from Divestiture of Interest in Joint Venture Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Legal Entity [Axis] Legal Entity [Axis] Equity ratio, percentage Public Utilities, Requested Equity Capital Structure, Percentage Cash and cash equivalents, at beginning of period Cash and cash equivalents, at end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code 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 Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Debt Instrument [Axis] Debt Instrument [Axis] Equity method investment, ownership percentage Equity Method Investment, Ownership Percentage General taxes Utilities Operating Expense, Taxes Capped portion of surety bond obligations Guarantor Obligations, Capped Portion of Surety Bond Obligations Guarantor Obligations, Capped Portion of Surety Bond Obligations Grid Growth EHV Holdings, LLC Grid Growth EHV Holdings, LLC [Member] Grid Growth EHV Holdings, LLC Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Axis] Customer [Domain] Customer [Domain] Investment, Name [Domain] Investment, Name [Domain] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Other Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount Assets, Current, Total Assets, Current Insider Trading Arrangements [Line Items] Award Type Award Type [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Affiliated companies Accounts receivable Accounts Receivable, after Allowance for Credit Loss, Current Retained earnings Retained Earnings (Accumulated Deficit) Depreciation and amortization Depreciation, Depletion, Amortization And Impairments Depreciation, Depletion, Amortization And Impairments Product and Service [Axis] Product and Service [Axis] Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Cover [Abstract] Remeasurement of excess deferred income taxes Effective Income Tax Rate Reconciliation, Remeasurement Of Excess Deferred Income Taxes, Amount Effective Income Tax Rate Reconciliation, Remeasurement Of Excess Deferred Income Taxes, Amount Reclassifications Reclassification, Comparability Adjustment [Policy Text Block] Noncontrolling interest Members' Equity Attributable to Noncontrolling Interest Equity Awards Adjustments Equity Awards Adjustments [Member] TOTAL LIABILITIES AND EQUITY Liabilities and Equity PJM 2025 RTEP Window 1 PJM 2025 RTEP Window 1 [Member] PJM 2025 RTEP Window 1 Employee Stock Option Share-Based Payment Arrangement, Option [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Construction work in progress Public Utilities, Property, Plant and Equipment, Construction Work in Progress Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Related Party [Domain] Related and Nonrelated Parties [Domain] Tabular List, Table Tabular List [Table Text Block] INVESTMENTS AND OTHER NONCURRENT ASSETS: Deferred Charges And Other Assets [Abstract] Deferred Charges And Other Assets Abstract. Miscellaneous income (expense), net Other Nonoperating Income (Expense) Total Members' Equity Parent [Member] 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] Equity contribution from FE First Energy (FE) [Member] First Energy (FE) PROPERTY, PLANT AND EQUIPMENT: Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization [Abstract] 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 Adjustment to Compensation: Adjustment to Compensation [Axis] Class of Stock [Domain] Class of Stock [Domain] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Capital investments Payments to Acquire Productive Assets Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Long-term debt and other long-term obligations Long-Term Debt and Lease Obligation Accounts payable - Affiliated companies Accounts payable Accounts Payable Name Measure Name INCOME TAXES Income Tax Disclosure [Text Block] Pay vs Performance Disclosure [Line Items] Debt Instrument [Line Items] Debt Instrument [Line Items] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Entity Filer Category Entity Filer Category Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Impairment of goodwill Goodwill, Impairment Loss Short-term borrowings Repayments of Short-Term Debt Other revenue unrelated to contracts with customers Revenue Not from Contract with Customer Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and Cash Equivalent Company Selected Measure Amount Company Selected Measure Amount TrAIL Trail [Member] TRAIL. NET INCOME Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Other Effective Income Tax Rate Reconciliation, Other Reconciling Items, Percent Valley Link Valley Link [Member] Valley Link CURRENT ASSETS: Assets, Current [Abstract] Non-PEO NEO Non-PEO NEO [Member] Entity Address, Address Line One Entity Address, Address Line One Regulatory Matters [Table] Regulatory Matters [Table] Regulatory matters. INCOME TAXES (BENEFITS) Total income taxes (benefits) Income Tax Expense (Benefit) Award Timing Method Award Timing Method [Text Block] Consolidation Consolidation, Policy [Policy Text Block] Net change in cash and cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Redemptions and repayments- Redemptions And Repayments [Abstract] Redemptions And Repayments Abstract. Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] 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. Variable Interest Entity, Primary Beneficiary Variable Interest Entity, Primary Beneficiary [Member] Members' equity Members' Capital EARNINGS ATTRIBUTABLE TO FIRSTENERGY TRANSMISSION, LLC Net Income (Loss) Attributable to Parent Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Senior Unsecured Notes Maturing 2033 At 5.19% Senior Unsecured Notes Maturing 2033 At 5.19% [Member] Senior Unsecured Notes Maturing 2033 At 5.19% Statement [Table] Statement [Table] Approved ROE Public Utilities, Approved Return on Equity, Percentage Restatement Determination Date: Restatement Determination Date [Axis] 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 Senior Unsecured Notes Maturing 2026 At 4.00% Senior Unsecured Notes Maturing 2026 At 4.00% [Member] Senior Unsecured Notes Maturing 2026 At 4.00% Receivables- Receivables, Net, Current [Abstract] 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. Short-term borrowings Proceeds from Short-Term Debt REVENUES: Revenues [Abstract] ORGANIZATION AND BASIS OF PRESENTATION Basis of Presentation and Significant Accounting Policies [Text Block] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] UNITED STATES