Finite-lived intangible assets, accumulated amortization Intangible liabilities, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Schedule of short-term borrowings and weighted-average interest rates Schedule of Short-Term Debt [Table Text Block] Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Award Timing Predetermined Award Timing Predetermined [Flag] Indefinite-lived Intangible Assets [Axis] Indefinite-Lived Intangible Assets [Axis] Entity File Number Entity File Number Additional paid in capital Additional Paid-in Capital [Member] Number of intervenors that filed for rehearing Number of intervenors that filed for rehearing Number of intervenors that filed for rehearing Tabular List, Table Tabular List [Table Text Block] Income Taxes [Table] Income Taxes [Table] Detailed information about the entity's income taxes. Schedule of significant related party transactions with ATC Schedule of Related Party Transactions [Table Text Block] Schedule of carrying value and fair value of financial instruments not recorded at fair value Fair Value, by Balance Sheet Grouping [Table Text Block] Energy Related Inventory Energy Related Inventory [Abstract] Total guarantees Guarantor Obligations, Maximum Exposure, Undiscounted Goodwill Goodwill [Line Items] Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Measurement Basis [Axis] Adjustment to Compensation: Adjustment to Compensation [Axis] First and Refunding Mortgage Bonds, Series ZZ PGL First and Refunding Mortgage Bonds, Series ZZ [Member] PGL First and Refunding Mortgage Bonds, Series ZZ Forward Contract Indexed to Issuer's Equity, Type [Domain] Forward Contract Indexed to Issuer's Equity, Type [Domain] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] REGULATORY ENVIRONMENT Public Utilities Disclosure [Text Block] OPERATING REVENUES Revenue from Contract with Customer [Text Block] Percentage of additional earnings between 15 and 75 basis points refunded to customers Percentage of additional earnings between 15 and 75 basis points refunded to customers Percentage of utility earnings in excess of 15 basis points above the utility’s authorized return on equity (ROE), but not exceeding 75 basis points above the authorized ROE, that will be refunded to customers. Schedule of Indefinite-Lived Intangible Liabilities [Table] Intangible Asset, Indefinite-Lived [Table] Cash collateral posted Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Offset Shares Issued - Stock investment plan Stock Issued During Period, Shares, Employee Stock Purchase Plans Schedule of net derivative instruments Net Derivative Instruments By Counterparty [Table Text Block] Tabular disclosure of derivative assets and liabilities if derivative instruments by counterparty were presented net on the balance sheets. Percentage of additional earnings between 15 and 40 basis points refunded to customers Percentage of additional earnings between 15 and 40 basis points refunded to customers Percentage of utility earnings in excess of 15 basis points above the utility’s authorized return on equity (ROE), but not exceeding 60 basis points above the authorized ROE, that will be refunded to customers. Contributions and payments related to pension and OPEB plans Contributions and payments related to pension and OPEB plans Payment for Pension and Other Postretirement Benefits Adjustment to Compensation, Amount Adjustment to Compensation Amount Pension Benefits Pension Plan [Member] Change in commercial paper Proceeds from (Repayments of) Short-Term Debt, Maturing in Three Months or Less Collateralized First Mortgage Bonds Collateralized First Mortgage Bonds [Member] Collateralized First Mortgage Bonds Weighted-average interest rate on amounts outstanding during the period Short-Term Debt, Weighted Average Interest Rate, over Time Consolidation Consolidation, Policy [Policy Text Block] Stock options Share-Based Payment Arrangement, Option [Member] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Prepaid taxes Prepaid Taxes Statutory rate reconciliation, percent Effective Income Tax Rate Reconciliation, Percent [Abstract] Members' equity Equity, Attributable to Parent Common stock dividends Dividends, Common Stock, Cash Measurement Frequency [Axis] Measurement Frequency [Axis] Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax [Abstract] Insider Trading Policies and Procedures [Line Items] May 2024 Rehearing Order May 2024 Rehearing [Member] Impacts from the rehearing order issued by the ICC in May 2024. Common stock, shares authorized Common Stock, Shares Authorized Surety bonds Surety Bond [Member] Bepoke resources current return Bepoke resources current return [Member] Revenue recognized associated with carrying costs, including financing costs, during the construction period of the bespoke resource Stock Issued During Period, Shares, New Issues Stock Issued During Period, Shares, New Issues Other current liabilities Increase (Decrease) in Other Current Liabilities Fair value measurements on a recurring basis Fair Value, Recurring [Member] Liabilities and Equity Liabilities and Equity [Abstract] Blooming Grove, Tatanka Ridge, Jayhawk, Thunderhead, Samson I, Sapphire Sky, Delilah I, and Hardin III Blooming Grove Wind Energy Center LLC, Tatanka Ridge Wind, LLC, Jayhawk Renewables, LLC, Thunderhead Wind LLC, Samson I Solar Energy Center LLC, Sapphire Sky Wind Energy LLCSky [Member] This element represents details pertaining to Blooming Grove Wind Energy Center LLC, Tatanka Ridge Wind, LLC, Jayhawk Renewables, LLC, Thunderhead Wind LLC, Samson I Solar Energy Center LLC, and Sapphire Sky Wind Energy LLC Types of Other Operating Revenues [Domain] Types of Other Operating Revenues [Domain] Types of Other Operating Revenues [Domain] Cover [Abstract] Cover [Abstract] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] DISPOSITION Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Maximum Maximum [Member] Length of proxy revenue contract, in years Finite-Lived Intangible Asset, Useful Life Fossil fuel Energy Related Inventory, Other Fossil Fuel Long-term Debt, Unclassified [Abstract] Long-Term Debt, Unclassified [Abstract] Net (income) loss attributed to noncontrolling interests Net income attributed to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Finite-lived intangible assets, net Finite-Lived Intangible Assets, Net Restricted shares Restricted Stock [Member] Whitetail Wind Energy Generating Facility Whitetail Wind Energy Generating Facility [Member] Whitetail Wind Energy Generating Facility Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Debt Instrument [Line Items] Debt Instrument [Line Items] Settlement related to QIP and UEA riders Settlement QIP UEA Riders [Member] Rate action of a regulator resulting in the capitalization or accrual of amounts that have to be returned to customers due to a settlement related to the qualifying infrastructure plant and uncollectible expense adjustment riders at The Peoples Gas Light and Coke Company and North Shore Gas Company. Reimbursement for ATC's transmission infrastructure upgrades Proceeds from Collection of Advance to Affiliate Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Retirement Benefits [Abstract] Retirement Benefits [Abstract] Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Income before income taxes Income before income taxes Pre-tax charge to income Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Proceeds from issuance of debt Proceeds from Issuance of Debt Regulatory assets Regulatory Asset [Line Items] Term of service agreements for wind and solar resources Term of service agreements for wind and solar resources Term of service agreements for wind and solar Bespoke Resources Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Operating Segments Operating Segments [Member] Schedule of additional information regarding the statements of cash flows Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Comprehensive (income) loss attributed to noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Line of Credit Facility [Table] Line of Credit Facility [Table] Short-term Debt [Abstract] Short-Term Debt [Abstract] Time period for PSCW to take action Time period for PSCW to take action Time period for PSCW to take action before a petition is deemed denied by operation of law. Letter of credit Letter of Credit [Member] Average amount of commercial paper outstanding during the period Short-Term Debt, Average Outstanding Amount Level 3 rollforward Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract] Schedule of Regulatory Liabilities [Table] Regulated Operation, Regulatory Liability [Table] Nontaxable or nondeductible items, percent Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent [Abstract] Document fiscal period focus Document Fiscal Period Focus Mercury and Air Toxics Standards Mercury and Air Toxics Standards [Member] Represents information related to the mercury and air toxics standards [Member] Amount to be refunded to customers each year Amount to be refunded to customers Amount of refunds that will be credited to customers in a given year. Award Timing Method Award Timing Method [Text Block] Basic (in dollars per share) Basic EPS Income (Loss) from Continuing Operations, Per Basic Share Award Type [Axis] Award Type [Axis] WEC Energy Group Parent Company [Member] Utility Plant [Domain] Utility Plant [Domain] Investment, Name [Domain] Investment, Name [Domain] Trading Symbol Trading Symbol Shares Issued - Stock-based compensation Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture Manufactured gas plant remediation Environmental Remediation Obligations [Abstract] Entity Address, City or Town Entity Address, City or Town Short-term Debt, Type [Domain] Short-Term Debt, Type [Domain] Weighted average discount rate Finance Lease, Weighted Average Discount Rate, Percent Forward Contract Indexed to Issuer's Equity [Table] Forward Contract Indexed to Issuer's Equity [Table] Transmission Affiliates Transmission Affiliates [Member] Represents American Transmission Company, LLC (ATC) and ATC Holdco, LLC. ATC is a for-profit, transmission only company that owns, maintains, monitors, and operates electric transmission assets. ATC Holdco, LLC is a separate entity formed to invest in transmission-related projects outside of ATC's traditional footprint. Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Income Statement Location [Domain] Statement of Income Location, Balance [Domain] Credit Losses Credit Loss, Financial Instrument [Policy Text Block] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Regulatory Agency [Axis] Regulatory Agency [Axis] CREDIT LOSSES Credit Loss, Financial Instrument [Text Block] Emerging growth company Entity Emerging Growth Company Other adjustments, amount Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount [Abstract] Amortization to be recorded as a decrease to other operation and maintenance Operating Expense [Member] Weighted average remaining lease term Finance Lease, Weighted Average Remaining Lease Term Cash collateral posted Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Not Offset 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] Gains (losses) Derivative, Gain (Loss) on Derivative, Net Add: Other Equity Method Investment Other Other items not separately disclosed that impact investments accounted for under the equity method of accounting. Indefinite-lived intangible asset Indefinite-Lived Intangible Assets (Excluding Goodwill) Rate Case Year [Axis] Rate Case Year [Axis] The year for which a rate case is filed. Less: Interest Finance Lease, Liability, Undiscounted Excess Amount Common stock, shares outstanding Common Stock, Shares, Outstanding, Beginning Balance Common Stock, Shares, Outstanding, Ending Balance Common Stock, Shares, Outstanding Provision for credit losses Accounts Receivable, Credit Loss Expense (Reversal) Very Large Customer and Bespoke Resources Tariffs Very Large Customer and Bespoke Resources Tariffs [Member] Application filed with the PSCW for the Very Large Customer Tariff and Bespoke Resources Tariff Operating revenues disaggregated by revenue source Disaggregation of Revenue [Table Text Block] Schedule of Common Stock Outstanding Roll Forward Schedule of Common Stock Outstanding Roll Forward [Table Text Block] We Power revenues We Power revenues [Member] Represents revenues consisting of the amortization of carrying costs recorded in deferred revenue and resulted from the previous construction of the We Power electric generating units. Pension and OPEB assets Assets for Plan Benefits, Defined Benefit Plan Income taxes paid (received) by jurisdiction, net Income Taxes [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Derivatives Deferred Derivative Gain (Loss) [Member] MPSC MichiganPublicServiceCommissionMPSC [Member] Represents the Michigan Public Service Commission (MPSC), which regulates the operations of Upper Michigan Energy Resources Corporation (UMERC) and Michigan Gas Utilities Corporation (MGU). Exercise of stock options Stock Issued During Period, Value, Stock Options Exercised 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] Schedule of Product Information [Table] Nature of Operation, Product Information, Concentration of Risk [Table] Schedule of amortization over the next five years Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Climate Change Climate Change [Member] Represents information related to climate change as defined by the EPA's Clean Power Plan. 2027 and 2028 Rates 2027 and 2028 Rate Case [Member] 2027 and 2028 Rate Case Guarantees expiring within 1 to 3 years Guarantee Obligations Maximum Exposure Expire Within One To Three Years Represents the maximum potential payments with respect to the entity's guarantees that expire within one to three years. Charges to ATC for services and construction Related Party Transaction, Charges To Related Party Charges to related parties for services, construction, and/or operations (excluding transactions that are eliminated in consolidated or combined financial statements) during the period. Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Income tax expense Total income tax expense, amount Income tax expense (benefit) Income Tax Expense (Benefit) PGL The Peoples Gas Light And Coke Company [Member] This element represents details pertaining to The Peoples Gas Light & Coke Company (PGL). Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Designated as hedging instrument Designated as Hedging Instrument [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Regulatory Assets and Liabilities Disclosure [Abstract] Regulatory Assets and Liabilities Disclosure [Abstract] Public Service Commission of Wisconsin (PSCW) Public Service Commission Of Wisconsin PSCW [Member] Represents the Public Service Commission of Wisconsin (PSCW), which regulates the operations of Wisconsin Public Service Corporation (WPS), Wisconsin Electric Power Company (WE), and Wisconsin Gas LLC (WG). Discontinued Operations and Disposal Groups [Abstract] Charge to income recorded in prior years Charge to income recorded in prior years Pre-tax charge to income recorded in prior years Other current assets Increase (Decrease) in Other Current Assets Schedule of Guarantor Obligations [Table] Guarantor Obligation [Table] Other Income and Expenses [Abstract] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Exercise of stock options Proceeds from Stock Options Exercised Other, net Other Nonoperating Income Federal Income Tax Paid, Federal, after Refund Received Pension and OPEB costs Pension and OPEB benefits Pension and Other Postretirement Plans Costs [Member] All Trading Arrangements All Trading Arrangements [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] MERC property tax tracker Property Tax [Member] Rate action of a regulatory resulting in capitalization or accrual of the difference between actual property tax expense and the amount included in rate. Preferred stock dividends of subsidiary Preferred Stock Dividends, Income Statement Impact Other, net, amount Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Requested Rate Increase (Decrease), Amount Public Utilities, Requested Rate Increase (Decrease), Amount Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Changes in unrecognized tax benefits, percent Effective Income Tax Rate Reconciliation, Tax Contingency, Percent [Abstract] Schedule of changes to our investments in transmission affiliates Schedule Of Changes To Equity Method Investments [Table Text Block] Tabular reconciliation of beginning and ending balances of investments accounted for under the equity method of accounting. Uncollectible expense Uncollectible Expense [Member] Rate action of a regulator resulting in capitalization or accrual of the difference between uncollectible expense recovered in rates and the actual uncollectible write-offs. Number of New Tariffs Number of New Tariffs Number of New Tariffs Net cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Total Utility Operations Public Utility [Member] Public utility operations Changes to the carrying amount of goodwill Goodwill, Period Increase (Decrease) Income Taxes Effective Income Tax Rate Reconciliation [Table] Equity Method Investments and Joint Ventures [Abstract] Equity Method Investments and Joint Ventures [Abstract] Subsequent event Subsequent Event [Member] Investment in transmission affiliates Other Income, Net [Line Items] Schedule of Equity Method Investments [Line Items] Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] PEO Total Compensation Amount PEO Total Compensation Amount Long-Term Debt, Type [Axis] Long-Term Debt, Type [Axis] Bluewater Bluewater [Member] Rate action of a regulator resulting in capitalization or accrual of the difference between actual storage costs and those included in rates. Wisconsin Wisconsin [Member] The Wisconsin segment includes the operations of Wisconsin Electric Power Company, Wisconsin Public Service Corporation, Wisconsin Gas LLC, and Upper Michigan Energy Resources Corporation. 2030 Finance Lease, Liability, to be Paid, Year Four Proxy revenue swap Swap [Member] Equity Components [Axis] Equity Components [Axis] Property, plant, and equipment Property, Plant and Equipment [Line Items] Standby letters of credit Standby Letters of Credit [Member] Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Number of reportable segments Number of Reportable Segments Amortization to be recorded as a decrease to operating revenues Amortization to be recorded as an increase to operating revenues Sales [Member] Schedule of summarized income statement data for ATC Schedule Of Equity Method Investments Summarized Income Statement Data [Table Text Block] Tabular disclosure of summarized income statement data related to significant equity method investments. Schedule of receivables and payables with ATC Schedule Of Related Party Transactions Balance Sheet Information [Table Text Block] Tabular disclosure of balance sheet information related to transactions entered into with related parties. VARIABLE INTEREST ENTITIES Variable Interest Entity Disclosure [Text Block] Regulatory liabilities Regulatory liabilities Regulatory Liability, Noncurrent Entity Address, State or Province Entity Address, State or Province Current liabilities Current liabilities Liabilities, Current QIP Settlement QIP Settlement Terms [Member] Settlement terms related to the open proceedings for the QIP rider. Individual: Individual [Axis] Approved return on equity (as a percent) Public Utilities, Approved Return on Equity, Percentage Income Tax Authority [Domain] Income Tax Jurisdiction [Domain] Right of use assets obtained in exchange for finance lease liabilities Right-of-Use Asset Obtained in Exchange for Finance Lease Liability Accounting Changes and Error Corrections [Abstract] Dividends paid on common stock Payments of Ordinary Dividends, Common Stock Minimum diameter of pipe that does not require replacement Minimum diameter of pipe that does not require replacement All cast and ductile iron pipe with a diameter under this amount requires replacement. Amortization Amortization Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Natural gas Natural Gas, US Regulated [Member] Retirement of long-term debt Repayments of Long-term Debt Repayments of Long-Term Debt Percentage of first 15 basis points of additional earnings retained by the utility Percentage of first 15 basis points of additional earnings retained by the utility Percentage of first 15 basis points of additional earnings retained by the utility Entity Interactive Data Current Entity Interactive Data Current Cash collateral Derivative, Collateral [Abstract] Upstream Upstream Wind Energy LLC [Member] Upstream Wind Energy LLC is a commercially operational wind generating facility located in Antelope County, Nebraska that supplies energy to the Southwest Power Pool. WEC 3.375% Convertible Notes due June 1, 2028 WEC 3.375% Convertible Notes due June 1, 2028 [Member] WEC 3.375% Convertible Notes due June 1, 2028 Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Pre-tax gain on sale of real estate Gains (Losses) on Sales of Other Real Estate Schedule of convertible debt interest expense Convertible Debt Interest Expense [Table Text Block] Convertible Debt Interest Expense Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Percentage of earnings in excess of 75 basis points refunded to customers Percentage of earnings in excess of 75 basis points refunded to customers Percentage of utility earnings in excess of 75 basis points above the utility’s authorized return on equity (ROE) that will be refunded to customers. New primary annual PM2.5 level New Primary Annual PM2.5 Level Represents the new primary annual PM2.5 level that the EPA finalized. Long-Lived Tangible Asset [Axis] Long-Lived Tangible Asset [Axis] 2027 Rates 2027 2027 Rates [Member] 2027 Rates Duration of offtake agreement for the sale of energy produced Duration of offtake agreement for the sale of energy produced Duration of offtake agreement for the sale of energy produced 2028 Finance Lease, Liability, to be Paid, Year Two Q2 2026 Forward Sales Contracts Q2 2026 Forward Sales Contracts [Member] Forward sales contracts that became effective during Q2 2026. Commercial paper outstanding Commercial Paper Other Other Assets, Noncurrent Other current liabilities (accrued interest) Interest Payable, Current Customer [Domain] Customer [Domain] Entity central index key Entity Central Index Key Other Other retail customer [Member] Represents customers in a sector of the economy consisting of companies engaged in other business activities PEO Name PEO Name AROs Asset Retirement Obligation Operating revenues Total operating revenues Reduction in revenues Revenues Option to purchase land Purchase Options, Land 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] Fair value measurements Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Removal costs Removal Costs [Member] Regulatory liabilities Regulatory Liability [Line Items] Capital contributions to transmission affiliates Add: Capital contributions Payments to Acquire Interest in Subsidiaries and Affiliates Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Period of time that the EPA may take to issue attainment designations Period of Time that the EPA May Take to Issue Attainment Designations Represents the period of time that the EPA may take to issue attainment designations Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan [Table] Schedule Of Segment Reporting Information By Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Gross amount not offset on the balance sheet Derivative Asset, Subject to Master Netting Arrangement, Gross Liability and Collateral, Obligation to Return Cash, Offset Nontaxable or nondeductible items, amount Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount [Abstract] Schedule of derivative assets and liabilities Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Exercise Price Award Exercise Price Entity filer category Entity Filer Category Notional volumes Derivative, Nonmonetary Notional Amount, Energy Measure United States federal statutory income tax rate, percent Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Subsequent Event Type [Axis] Subsequent Event Type [Axis] Long-term debt (June 30, 2026 and December 31, 2025 include $62.8 and $67.4, respectively, related to WEPCo Environmental Trust) Long-term debt Long-Term Debt, Excluding Current Maturities 2028 Finite-Lived Intangible Asset, Expected Amortization, Year Three Gross carrying amount Finite-Lived Intangible Assets, Gross 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] Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Accumulated other comprehensive loss AOCI Attributable to Parent [Member] Accounts receivable and unbilled revenues, reserves Accounts Receivable, Allowance for Credit Loss, Current Amended Renewable Energy Plan Amended Renewable Energy Plan [Member] Amended Renewable Energy Plan required to be filed in Michigan under Public Act 235. Common stock issued for stock-based compensation plans Stock Issued Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract] Manufactured Gas Plant Remediation Manufactured Gas Plant Remediation [Member] Represents remediation related to manufacturing gas and storing manufactured gas. DERIVATIVE INSTRUMENTS Derivative Instruments and Hedging Activities Disclosure [Text Block] Amortization of prior service credit Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Changes in unrecognized tax benefits, amount Effective Income Tax Rate Reconciliation, Tax Contingency, Amount [Abstract] DISPOSITION Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Fair Value as of Grant Date Award Grant Date Fair Value FTRs FTRs and TCRs Commodity Contract Transmission Congestion Rights [Member] Derivative instrument used to manage electric transmission congestion costs. Schedule of other income, net Schedule of Other Nonoperating Income (Expense) [Table Text Block] Changes in unrecognized tax benefits, amount Effective Income Tax Rate Reconciliation, Tax Contingency, Amount WG Wisconsin Gas LLC [Member] This element represents details pertaining to Wisconsin Gas LLC (WG). Minimum future commitments for purchase obligations Unconditional Purchase Obligations (Excluding Capital Stock Redemptions) [Abstract] Dilutive effect of stock-based compensation awards Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Net Share Settlement Net Share Settlement [Member] Awards granted Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Refunds required to customers Refunds required to customers The total amount required to be refunded to customers as a result of a legal settlement or order. Total operating expenses Operating expenses Costs and Expenses Document Quarterly Report Document Quarterly Report Deferred income taxes and ITCs, net Deferred Income Taxes and Tax Credits Fair value amount Long-Term Debt, Fair Value Finance and operating leases Finance Operating Leases [Member] Rate action of a regulator resulting in capitalization or accrual of the difference between lease expense recovered in rates and lease expense calculated under Accounting Standards Codification 842. Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Previous limit of particulate matter, in pounds per million british thermal unit Previous Level of Particulate Matter in Pounds per Million British Thermal Unit Previous Level of Particulate Matter in Pounds per Million British Thermal Unit prior to the EPA's final rule published in the Federal Register in May 2024. Lease [Domain] Counterparty Name [Domain] GUARANTEES Guarantees [Text Block] Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Requested return on equity (as a percent) Public Utilities, Requested Return on Equity, Percentage Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Residential Residential customer [Member] Represents customers of a sector of the economy consisting of residential dwellings. Non-PEO NEO Non-PEO NEO [Member] Letters of credit issued inside credit facilities Letters of Credit Outstanding, Amount Forward Contract Indexed to Equity, Settlement, Number of Shares Forward Contract Indexed to Equity, Settlement, Number of Shares Shares issued - At-the-market offering program Shares issued - At-the-market offering program Number of shares issued during the period as a result of an at-the-market offering program. Number of applicable GHG performance standards for coal plants Number of Applicable GHG Performance Standards for Coal Plants Represents the number of applicable GHG performance standards applicable to Coal Plants until 2032. Sale of Stock [Axis] Sale of Stock [Axis] Schedule of regulatory liabilities Schedule of Regulatory Liabilities [Table Text Block] Award Type [Domain] Award Type [Domain] Statement of Other Comprehensive Income [Abstract] Statement of Other Comprehensive Income [Abstract] Equity Awards Adjustments Equity Awards Adjustments [Member] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] 4.65% $400M WE Debentures due 06/15/2031 4.65% $400M WE Debentures due 06/15/2031 [Member] 4.65% $400M WE Debentures due 06/15/2031 Disaggregation of Operating Revenues Disaggregation of Revenue [Line Items] Employee Benefit Plans Defined Benefit Plan Disclosure [Line Items] Accounts receivable and unbilled revenues, net Increase (Decrease) in Accounts and Other Receivables Compensation Amount Outstanding Recovery Compensation Amount Other, percent Effective Income Tax Rate Reconciliation, Other Reconciling Items, Percent Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Fair value Estimate of Fair Value Measurement [Member] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Level of particulate matter in pounds per million british thermal unit that the EPA reverted back to with the repeal of the 2024 amendments New Level of Particulate Matter in Pounds per Million British Thermal Units Represents the level of particulate matter in pounds per million british thermal units that the EPA reverted back to with a final rule repealing the 2024 Amendments in February 2026. Schedule of Investments [Line Items] Schedule of Investments [Line Items] Rollforward of the allowances for credit losses by reportable segment Accounts Receivable, Allowance for Credit Loss [Table Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Six Months Ended December 31, 2026 Finance Lease, Liability, to be Paid, Remainder of Fiscal Year Tax credits, amount Effective Income Tax Rate Reconciliation, Tax Credit, Amount [Abstract] Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Air quality Environmental Compliance Obligations Air Quality [Abstract] -- None. No documentation exists for this element. -- Performance units Performance Shares [Member] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Reclassification of realized derivative gains to net income, net of tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Finite-Lived Intangible Asset by Major Class [Axis] Finite-Lived Intangible Liabilities by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Other adjustments, percent Effective Income Tax Rate Reconciliation, Other Reconciling Items, Percent [Abstract] Total balance sheet impact recorded Total balance sheet impact recorded Total balance sheet impact recorded for the rate base reduction and the obligation to refund amounts to customers through bill credits. Minimum Minimum [Member] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Company Selected Measure Name Company Selected Measure Name Reserves for future environmental remediation Accrual for Environmental Loss Contingencies Fair Value Measurement [Domain] Fair Value Measurement [Domain] Changes to investments in transmission affiliates Equity Method Investments [Roll Forward] A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Accounts payable Accounts payable for services received from ATC Accounts Payable, Current Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] WEC 4.375% Convertible Notes due June 1, 2027 WEC 4.375% Convertible Notes due June 1, 2027 [Member] WEC 2027 Convertible Notes Goodwill balance by segment Goodwill [Roll Forward] Amortization to be recorded in the next five years Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract] COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Current derivative liabilities balance sheet location Derivative Liability, Current, Statement of Financial Position [Extensible Enumeration] Schedule of Regulatory Assets [Table] Regulated Operation, Regulatory Asset [Table] Diluted (in shares) Weighted average diluted shares Weighted Average Number of Shares Outstanding, Diluted Weighted average interest rate on amounts outstanding Short-Term Debt, Weighted Average Interest Rate, at Point in Time Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Derivative [Table] Derivative [Table] Other prepayments Other Prepaid Expense, Current Smaller reporting company Entity Small Business Alternative revenues Alternative revenues utility [Member] Represents revenues that are created from programs authorized by regulators that allow utilities to record additional revenues by adjusting rates in the future. Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Other operation and maintenance Other Cost and Expense, Operating LONG-TERM DEBT Long-Term Debt [Text Block] Document Transition Report Document Transition Report Reconciliation of changes in fair value of items categorized as level 3 measurements Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Total minimum lease payments Finance Lease, Liability, to be Paid Underlying Securities Award Underlying Securities Amount Late payment charges Late payment charges [Member] Represents revenues from late payment charges Equity Component [Domain] Equity Component [Domain] Document period end date Document Period End Date Additional capital spend approved us-gaap_PublicUtilitiesApprovedAdditionalCapitalSpend Amount of additional capital spend approved by the state regulatory commission. INCOME TAXES Income Tax Disclosure [Text Block] Period of amortization Period of amortization Period of amortization over a future period of time Allowance for credit losses Balance at beginning of period Balance at end of period Accounts Receivable, Allowance for Credit Loss Tax Cuts And Jobs Act Of 2017 Tax Cuts And Jobs Act Of 2017 [Member] Information related to the Tax Cuts and Jobs Act of 2017. This act was signed into law on December 22, 2017. Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Schedule of Investments [Table] Schedule of Investments [Table] Net amount Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction OCPP OCPP [Member] Oak Creek Power Plant (OCPP), which is owned by WE. Balance Balance Equity, Including Portion Attributable to Noncontrolling Interest Estimated cost of project Estimated cost of project Total estimated cost of project Refund Year [Domain] Refund Year [Domain] Refund Year Forward Contract Indexed to Issuer's Equity [Line Items] Forward Contract Indexed to Issuer's Equity [Line Items] Document type Document Type Level 3 Fair Value, Inputs, Level 3 [Member] Name Outstanding Recovery, Individual Name Loss Contingencies [Table] Loss Contingencies [Table] Accounts receivable for services provided to ATC Accounts and Other Receivables, Net, Current Product and Service [Axis] Product and Service [Axis] Asset Acquisition [Domain] Asset Acquisition [Domain] Appliance service revenues 811412 Appliance Repair and Maintenance [Member] Revenues from contracts with customers Revenue from Contract with Customer Benchmark [Member] Revenues from contracts with customers Revenue from Contract with Customer, Excluding Assessed Tax Requested Rate Increase (Decrease), Amended, Percentage Public Utilities, Requested Rate Increase (Decrease), Amended, Percentage UMERC UMERC [Member] This element represents details pertaining to Upper Michigan Energy Resources Corporation (UMERC). Acquisition purchase price Asset Acquisition, Consideration Transferred Current assets Current assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] Electric Electricity, US Regulated [Member] Amounts due from ATC for transmission infrastructure upgrades Other Receivables, Net, Current Regulatory Asset [Domain] Regulatory Asset [Domain] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Net income attributed to common shareholders Net income attributed to common shareholders Net income (loss) attributed to common shareholders Net Income (Loss) Available to Common Stockholders, Basic Other current assets Regulatory Asset, Current Insurance receivable Insurance Settlements Receivable Current liabilities Liabilities, Current [Abstract] Proceeds from sale of real estate Proceeds from Sale of Real Estate Impairments related to Illinois segment Impairments Related to Illinois Segment The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale) in our Illinois segment Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Charges from ATC for network transmission services Operating Expenses PTCs, net, amount Effective Income Tax Rate Reconciliation, Tax Credit, Energy-Related, Amount Level 1 Fair Value, Inputs, Level 1 [Member] Other, amount Effective Income Tax Rate Reconciliation, Tax Credit, Other, Amount Accounts receivable and unbilled revenues, net of reserves of $148.9 and $148.7, respectively Accounts Receivable, after Allowance for Credit Loss, Current Forward Contract Indexed to Issuer's Equity, Initial Forward Price Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share Pension and Other Postretirement Plans Cost Pension and Other Postretirement Plans Cost [Member] Rate action of regulatory resulting in escrow accounting of pension/OPEB costs Dividends [Axis] Dividends [Axis] State Income Tax Paid, State and Local, after Refund Received Consolidation Items [Domain] Consolidation Items [Domain] INVESTMENT IN TRANSMISSION AFFILIATES Equity Method Investments and Joint Ventures Disclosure [Text Block] Asset Acquisition [Table] Asset Acquisition [Table] Resale Resale Customers [Member] Represents customers of a sector of the economy who purchase energy from an energy market operated by MISO at market rates based on availability of the utilities' generation and market demand. Public Utilities General Disclosures [Table] Public Utilities General Disclosures [Table] Schedule of income taxes paid (received) by jurisdiction Schedule of cash paid (received) for income taxes [Table Text Block] Schedule of income taxes paid (received) by jurisdiction Rate Case Year [Domain] Rate Case Year [Domain] Rate Case Year [Domain] Rate2018And2019 Rate2018And2019 [Member] Settlement agreement filed by Wisconsin Electric Power Company, Wisconsin Gas LLC, and Wisconsin Public Service Corporation for their 2018 and 2019 rates. Regulatory Liability [Domain] Regulatory Liability [Domain] Stock-based compensation and other Stockholders' Equity, Other LIFO Method Related Items LIFO Method Related Items [Abstract] Net realized and unrealized gains included in earnings Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings Total income taxes received, net Income Taxes Paid, Net Illinois Commerce Commission (ICC) Illinois Commerce Commission ICC [Member] Represents the Illinois Commerce Commission (ICC), which regulates the operations of The Peoples Gas Light and Coke Company (PGL) and the operations of North Shore Gas Company (NSG). Qualified infrastructure investment costs to be removed from rate base Public Utilities, Property, Plant and Equipment, Amount of Indirect Disallowance of Costs of Recently Completed Plants 2027 Finite-Lived Intangible Asset, Expected Amortization, Year Two Past due greater than 90 days - collection risk mitigated by regulatory mechanisms Percent of accounts receivable past due greater than 90 days, with regulatory mechanisms to collect Percent of accounts receivable past due greater than 90 days with regulatory mechanisms to mitigate collection risk Stock options granted, weighted average exercise price Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price PROPERTY, PLANT, AND EQUIPMENT Property, Plant and Equipment Disclosure [Text Block] WE Wisconsin Electric Power Company [Member] This element represents details pertaining to Wisconsin Electric Power Company (WE). Distributions to noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders UEA Rider Settlement Terms UEA Rider Settlement Terms [Member] Settlement terms approved by the ICC related to the open proceedings for the UEA rider. Dividends [Domain] Dividends [Domain] Reconciling eliminations Intersegment Eliminations [Member] Expiration Date Trading Arrangement Expiration Date 2030 Finite-Lived Intangible Asset, Expected Amortization, Year Five Product information [Line Items] Product Information [Line Items] Requested common equity component average (as a percent) Public Utilities, Requested Equity Capital Structure, Percentage Settlement alternatives [Axis] Settlement alternatives [Axis] Settlement alternatives Property, plant, and equipment, net of accumulated depreciation and amortization of $12,783.3 and $12,411.5, respectively Property, Plant and Equipment, Net Hardin Solar Energy III Center Hardin Solar III Energy Center [Member] Hardin Solar III Energy Center is a solar generating facility located in Hardin County, Ohio. Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Entity Current Reporting Status Entity Current Reporting Status Energy efficiency programs Energy Efficiency Programs [Member] Rate action of a regulator resulting in capitalization or accrual of costs related to energy efficiency programs. Derivative instruments Derivative [Line Items] Impairment due to storm damage Impairment of Ongoing Project Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Consolidated Entities [Domain] Consolidated Entities [Domain] Schedule of future minimum lease payments Finance And Operating Lease Liability Maturity [Table Text Block] Tabular disclosure of undiscounted cash flows for finance and operating lease liabilities. Includes, but is not limited to, reconciliation of undiscounted cash flows to finance and operating lease liabilities recognized in the statement of financial position. United States federal statutory income tax rate, amount Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Gross amount recognized on the balance sheet Derivative Liability, Gross Liability Including Not Subject to Master Netting Arrangement AFUDC-Equity, percent Effective Income Tax Reconciliation Allowance For Funds Used During Construction Capitalized Cost Of Equity Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to the equity portion of allowance for funds used during construction. WEC 4.75% Senior Notes $1000M due January 9, 2026 WEC 4.75% Senior Notes $1000M due January 9, 2026 [Member] WEC 4.75% Senior Notes $1000M due January 9, 2026 Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Executive Category: Executive Category [Axis] Q4 2025 Forward Sales Contract Q4 2025 Forward Sales Contract [Member] Q4 2025 Forward Sales Contract State and local income taxes net of federal tax effect, percent Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Less: short-term lease liabilities Finance Lease, Liability, Current Interest expense Interest Expense, Operating and Nonoperating Issuance of long-term debt Proceeds from Issuance of Long-Term Debt Current fiscal year end date Current Fiscal Year End Date Interconnection agreements Service Agreements [Member] Finite-Lived Intangible Asset, Major Class Name [Domain] Finite-Lived Intangible Liabilities, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Schedule of gross receivables and related allowances for credit losses Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Schedule of outstanding guarantees Schedule of Guarantor Obligations [Table Text Block] Noncontrolling interests Other Noncontrolling Interests Derivative liabilities Total derivative liabilities Derivative Liability Stock options granted, weighted-average grant date fair value Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Natural gas storage needs provided to Wisconsin utilities PercentageOfStorageNeedsProvidedByStorageFacility Percentage of the company's Wisconsin natural gas storage needs provided by the natural gas storage facility. LIFO liquidation credit Excess of Replacement or Current Costs over Stated LIFO Value Less: Distributions Proceeds from Equity Method Investment, Distribution Schedule of fair value of assets and liabilities measured on a recurring basis categorized by level within the fair value hierarchy Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] System support resource SystemSupportResource [Member] Rate action of a regulator resulting in capitalization or accrual of the difference between the amount of system support resource payments from the Midcontinent Independent System Operator (MISO) authorized for recovery and the amount actually received. Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Forward Contract Indexed to Equity, Settlement, Cash, Amount Forward Contract Indexed to Equity, Settlement, Cash, Amount Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Net cash provided by (used in) financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Measure: Measure [Axis] Defined benefit plans Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax [Abstract] ATC Holdco ATC Holdco LLC ATC Holdco LLC [Member] Information related to ATC Holdco, LLC, a separate entity formed in December 2016 to invest in transmission-related projects outside of ATC's traditional footprint. Previous level of micrograms per cubic meter under 24-hour standard that particulate matter needed to be below Previous Level of Micrograms per Cubic Meter Under 24-Hour Standard that Particulate Matter Needed to be Below Previous Level of Micrograms per Cubic Meter Under 24-Hour Standard that Particulate Matter Needed to be Below Long-Lived Tangible Asset [Domain] Long-Lived Tangible Asset [Domain] Cost of sales Cost of Product and Service Sold Forward Contract Indexed to Issuer's Equity, Shares Forward Contract Indexed to Issuer's Equity, Shares Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Other, net Other Regulatory Assets (Liabilities) [Member] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Amortization of debt issuance costs Amortization of Debt Issuance Costs Public Utilities, General Disclosures [Line Items] Public Utilities, General Disclosures [Line Items] Entity Tax Identification Number Entity Tax Identification Number Change in allowance for credit losses Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease) Net unrealized gains included in earnings related to investments held at end of period Equity Securities, FV-NI, Unrealized Gain Asset Acquisition [Axis] Asset Acquisition [Axis] Schedule of balance sheet impact of WEPCo Environmental Trust Finance I, LLC Schedule of Variable Interest Entities [Table Text Block] Common Stock, Shares, Issued Common Stock, Shares, Issued Total regulatory liabilities Regulatory liabilities Regulatory Liability Types of Operating Revenues [Domain] Types of Operating Revenues [Domain] Types of Operating Revenues [Domain] GOODWILL AND INTANGIBLES Goodwill and Intangible Assets Disclosure [Text Block] Schedule of goodwill balance by segment Schedule of Goodwill [Table Text Block] Trading Arrangement: Trading Arrangement [Axis] Current derivative assets Derivative Asset, Current Total Shareholder Return Amount Total Shareholder Return Amount Types of Operating Revenues [Axis] Types of Operating Revenues [Axis] The disaggregating of operating revenues into different types. Environmental matters Loss Contingencies [Line Items] Security Exchange Name Security Exchange Name Acquisition purchase price, expected Asset Acquisition, Price of Acquisition, Expected Reconciliation of cash, cash equivalents, and restricted cash Reconciliation Of Cash And Restricted Cash [Table Text Block] Tabular reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets to the amounts shown in the statements of cash flows. Long-term liabilities Liabilities, Noncurrent Accounts payable related to construction costs Capital Expenditures Incurred but Not yet Paid Short-term credit capacity Line of Credit Facility, Maximum Borrowing Capacity Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-Lived Intangible Assets, Major Class Name [Domain] Operating expenses Operating Expenses [Abstract] Samson I Solar Energy Center Samson I Solar Energy Center LLC [Member] Samson I Solar Energy Center LLC is a commercially operational solar generating facility located in Lamar County, Texas. Other Other Liabilities, Current Condensed consolidated financial statements Statement [Line Items] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Cash and cash equivalents Cash and Cash Equivalent Common stock Common Stock [Member] Finance leases Finance Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract] Operating expense loan outstanding Other Short-Term Borrowings 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 Guarantees Guarantor Obligations [Line Items] Statistical Measurement [Domain] Statistical Measurement [Domain] Amortization of pension and OPEB costs included in net periodic benefit cost, net of tax Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax Other current assets (restricted cash) Restricted cash included in other current assets Restricted Cash, Current Equity in earnings of transmission affiliates Earnings (losses) from equity method investments Income (Loss) from Equity Method Investments Leases [Abstract] Leases [Abstract] EPS Earnings Per Share, Basic [Abstract] Other non-utility revenues Other non-utility revenues [Member] Represents revenues not regulated under public utility regulations. These revenues include revenues from We Power, appliance service revenues, and distributed renewable solar project revenues. Fuel and purchased power costs Fuel and purchased power costs Fuel and purchased power costs Net refund (payment) from (to) ATC related to FERC ROE orders ATC Net Refunds For FERC ROE Orders Net refunds of transmission charges received from American Transmission Company LLC as a result of return on equity orders issued by the Federal Energy Regulatory Commission. Accounts payable Increase (Decrease) in Accounts Payable Deferred revenue, net Deferred Revenue, Noncurrent Weighted average common shares outstanding Weighted Average Common Shares Outstanding Millions [Abstract] Weighted Average Common Shares Outstanding (Millions). Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Capacity of fossil-fueled generation retired, in megawatts Coal Generation Capacity Retired The capacity, in megawatts, of coal generation retired since the beginning of 2018 Schedule of credit agreements and remaining available capacity Schedule of Line of Credit Facilities [Table Text Block] Commercial paper Commercial Paper [Member] Renewable generation revenues Alternative Energy [Member] Changes in unrecognized tax benefits, percent Effective Income Tax Rate Reconciliation, Tax Contingency, Percent Other comprehensive income (loss), net of tax Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Schedule of financial information related to our reportable segments Schedule of Segment Reporting Information, by Segment [Table Text Block] Inventory Disclosure [Abstract] Inventory Disclosure [Abstract] Short-term debt Short-Term Debt Requested Rate Increase (Decrease), Amended, Amount Public Utilities, Requested Rate Increase (Decrease), Amended, Amount 2029 Finance Lease, Liability, to be Paid, Year Three Indefinite-lived Intangible Assets Indefinite-Lived Intangible Assets [Line Items] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Proceeds from the sale of assets Proceeds from Sale of Productive Assets WEPCo Environmental Trust WEPCo Environmental Trust Finance I, LLC Variable Interest Entity, Primary Beneficiary [Member] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Accounts and Financing Receivables [Table] Public Utilities, Regulatory Proceeding [Domain] Public Utilities, Regulatory Proceeding [Domain] Utility operations Public Utilities Public Utilities [Member] Hedging Designation [Domain] Hedging Designation [Domain] Shares Issued - 401(k) Stock Issued During Period, Shares, Employee Benefit Plan Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Secured Debt Secured Debt Current assets Assets, Current [Abstract] Total liabilities and equity Total liabilities and members' equity Liabilities and Equity Total accounts receivable, net - past due greater than 90 days Accounts Receivable, Past Due Greater than 90 Days Amount of accounts receivable past due greater than 90 days Offsetting derivative assets Offsetting Derivative Assets [Abstract] Long-term derivative assets balance sheet location Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration] Electric transmission costs Electric Transmission Costs [Member] Rate action of a regulator resulting in capitalization or accrual of electric transmission costs. Schedule of Equity Method Investments [Table] Equity Method Investment [Table] Capital expenditures and asset acquisitions Segment, Expenditure, Addition to Long-Lived Assets Accounting Policies [Abstract] Accounting Policies [Abstract] Guarantees [Abstract] Guarantees [Abstract] Public Utility [Axis] Public Utility [Axis] ACQUISITIONS Asset Acquisition [Text Block] Long-term derivative liabilities balance sheet location Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Realized gains and losses Derivative, Gain (Loss) on Derivative, Net [Abstract] Dividends payable Dividends Payable [Line Items] Pay vs Performance Disclosure [Line Items] SMP Proceedings SMP Proceedings [Member] Proceeding held by the ICC to determine the optimal method for replacing aging natural gas infrastructure and a prudent investment level. Liabilities Liabilities [Abstract] Acquisition of noncontrolling interests Noncontrolling Interest, Increase from Business Combination Other Other noncurrent liabilities Other Liabilities, Noncurrent Schedule of Variable Interest Entities [Table] Variable Interest Entity [Table] Asset Acquisition [Line Items] Statement of Cash Flows [Abstract] Current portion of long-term debt (June 30, 2026 and December 31, 2025 include $9.4 and $9.3, respectively, related to WEPCo Environmental Trust) Current portion of long-term debt Long-Term Debt, Current Maturities Company Selected Measure Amount Company Selected Measure Amount Derivatives accounted for as cash flow hedges Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract] Comprehensive income attributed to common shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Name Measure Name Number Of Customers Number Of Customers The number of customers served by the entity. Sales Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Sales Deferred income taxes Deferred Income Tax Liabilities, Net Gross amount not offset on the balance sheet Derivative Liability, Subject to Master Netting Arrangement, Gross Asset and Collateral, Right to Reclaim Cash, Offset Net carrying amount Long-term debt, including current portion Long-Term Debt Legal Entity [Axis] Legal Entity [Axis] Total assets Total assets Assets Income tax related items Deferred Income Tax Charge [Member] 2026 Finite-Lived Intangible Asset, Expected Amortization, Year One Other Other Operating Revenues-Other [Member] Represents other operating revenues that are not significant. Small commercial and industrial Small commercial and industrial [Member] Represents customers in a sector of the economy consisting of companies engaged in small commercial and industrial activities. Regulatory Liability [Axis] Regulatory Liability [Axis] Income taxes Income Tax, Policy [Policy Text Block] AROs Asset Retirement Obligation Costs [Member] Operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract] Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract] Number of years between evaluation of attainment status Number of Years Between Evaluation of Attainment Status Number of years between evaluation of attainment status until attainment is achieved. Weighted average remaining useful life Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life MATERIALS, SUPPLIES, AND INVENTORIES Inventory Disclosure [Text Block] Disallowed capital costs Public Utilities, Property, Plant and Equipment, Amount of Disallowed Costs for Recently Completed Plant Delilah Solar Energy LLC Delilah Solar Energy LLC [Member] Delilah Solar Energy LLC Other States Other States [Member] The other states segment includes the natural gas utility and non-utility operations of Minnesota Energy Resources Corporation and Michigan Gas Utilities Corporation. Other utility revenues Other utility [Member] Represents a customer whose revenues are a part of multiple customer classes combined or not specifically identifiable to any one customer. Variable interest entities Variable Interest Entity [Line Items] 2029 Finite-Lived Intangible Asset, Expected Amortization, Year Four 2027 Finance Lease, Liability, to be Paid, Year One Common stock dividend declared (in dollars per share) Common Stock, Dividends, Per Share, Declared Entity common stock, shares outstanding Entity Common Stock, Shares Outstanding Level 2 Fair Value, Inputs, Level 2 [Member] National Ambient Air Quality Standards National Ambient Air Quality Standards [Member] Represents information related to the National Ambient Air Quality Standards State and local income taxes net of federal tax effect, amount Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Schedule of regulatory assets Schedule of Regulatory Assets [Table Text Block] SHORT-TERM DEBT AND LINES OF CREDIT Short-Term Debt [Text Block] Investment in transmission affiliates, balance at beginning of period Investment in transmission affiliates, balance at end of period Equity method investments Equity method investment Equity Method Investments Steam Downtown Milwaukee Steam Customers [Member] Represents the Downtown Milwaukee (Valley) steam utility customers served by Wisconsin Electric Power Company. Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Schedule of regulatory requests Public Utilities General Disclosures [Table Text Block] REGULATORY ASSETS AND LIABILITIES Schedule of Regulatory Assets and Liabilities [Text Block] PEO PEO [Member] Interest income Investment Income, Interest Significant non-cash investing and financing transactions Noncash Investing and Financing Items [Abstract] Corporate and Other Corporate Segment and Other Operating Segment [Member] Change in – Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] WPS 4.25% $300M Senior Notes due January 15, 2031 WPS 4.25% $300M Senior Notes due January 15, 2031 [Member] WPS 4.25% $300M Senior Notes due January 15, 2031 Retained earnings Retained Earnings [Member] Income Tax Authority [Axis] Income Tax Jurisdiction [Axis] Cash, cash equivalents, and restricted cash at beginning of period Cash, cash equivalents, and restricted cash at end of period Cash, cash equivalents, and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement [Abstract] Income Statement [Abstract] Derivative assets Total derivative assets Derivative Asset Refund Year [Axis] Refund Year [Axis] Refund Year At-the-market program offering At-the-market program offering [Member] Information about shares issued through an at-the-market program offering. Sale of Stock [Domain] Sale of Stock [Domain] Long-term derivative liabilities Derivative Liability, Noncurrent Federal excess deferred tax amortization, amount Income Tax Reconciliation Federal Excess Amortization Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to federal excess deferred tax amortization. Leases acquired during Q2 2026 Leases acquired during Q2 2026 [Member] Leases acquired during Q2 2026 Ownership interest of solar generating facility acquired Ownership interest of solar generating facility acquired Ownership interest of solar generating facility acquired Product and Service [Domain] Product and Service [Domain] Contractual interest expense Interest Expense, Debt, Excluding Amortization Diluted (in dollars per share) Diluted EPS Income (Loss) from Continuing Operations, Per Diluted Share Total common shareholders' equity Parent [Member] Net income Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] AFUDC-Equity AFUDC - Equity Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity City Area Code City Area Code Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Decoupling Decoupling [Member] Rate action of a regulator resulting in capitalization or accrual of the differences between actual and authorized margins for certain customer classes. WEC 4.375% Convertible Notes due June 1, 2029 WEC 4.375% Convertible Notes due June 1, 2029 [Member] WEC 2029 Convertible Notes Schedule of stock-based compensation awards granted ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantedinPeriod [Table Text Block] Tabular disclosure of the number of equity awards granted during the period, including the weighted-average grant-date fair value and the weighted-average exercise price per award. Investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] PTCs sold to third parties Sale of production tax credit cash received Cash received during the period from the sale of production tax credits to third parties. Amortization of net actuarial (gain) loss Defined Benefit Plan, Amortization of Gain (Loss) Income Taxes Effective Income Tax Rate Reconciliation [Line Items] Investments held in rabbi trust Equity Securities, FV-NI Goodwill Goodwill Goodwill Approved rate increase (as a percent) Public Utilities, Approved Rate Increase (Decrease), Percentage Gains from investments held in rabbi trust Gain (Loss) on Investments Wholesale Wholesale customer [Member] Represents a customer in a sector of the economy consisting of companies engaged in purchasing electric service from the utility and then reselling this electric service to their customers. First and Refunding Mortgage Bonds, Series VV PGL First and Refunding Mortgage Bonds, Series VV [Member] PGL First and Refunding Mortgage Bonds, Series VV Asset Acquisition [Abstract] Supplemental cash flow information Supplemental Cash Flow Information [Abstract] Balance at the beginning of the period Balance at the end of the period Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs Tatanka Ridge and Bishop Hill III Tatanka Ridge Wind LLC and Bishop Hill Energy III LLC [Member] This element represents details pertaining to Tatanka Ridge Wind LLC and Bishop Hill Energy III LLC Total retail revenues Total Retail Customers [Member] Represents a sector of the economy consisting of companies engaged in residential, commercial and industrial and other retail revenues. Accumulated impairment losses Goodwill, Impaired, Accumulated Impairment Loss WECI WEC Infrastructure LLC [Member] This element represents details pertaining to WEC Infrastructure LLC (WECI), a subsidiary of WEC Energy Group, Inc. Other Performance Measure, Amount Other Performance Measure, Amount Number of factors the decision to postpone the retirement date was based on Number of Factors The Decision to Postpone the Retirement Date Was Based On Represents the number of factors the decision to postpone the retirement date of the OCPP units 7 and 8 was based on Fair value measurements Fair Value Measurement, Policy [Policy Text Block] Statutory rate reconciliation, amount Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract] Derivative Instrument [Axis] Derivative Instrument [Axis] Financial instruments Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Types of Non-Utility Operating Revenues [Domain] Types of Non-Utility Operating Revenues [Domain] [Domain] for Disaggregates non-utility operating revenues. Other Other Assets, Current Additional paid in capital Additional Paid in Capital, Common Stock Entity [Domain] Entity [Domain] Net cash used in investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity investment in transmission affiliates Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures 2016 Annual QIP Rider Reconciliation 2016 Annual QIP Rider Reconciliation [Member] 2016 Annual QIP Rider Reconciliation Securitization Securitization Costs [Member] Rate action of a regulator resulting in capitalization or accrual of costs securitized (financed with debt) and recoverable through an approved charge. 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] Acquisition of Hardin III, net of cash acquired of $— and $0.2, respectively Payments to Acquire Assets, Investing Activities Long-term derivative assets Derivative Asset, Noncurrent Percentage to be refunded to customers each year Percentage to be refunded to customers Percentage of refunds that will be credited to customers in a given year. Cash paid for interest, net of amount capitalized Interest Paid, Excluding Capitalized Interest, Operating Activity Other Operating Revenues [Abstract] Other Operating Revenues [Abstract] Other Operating Revenues [Abstract] Document fiscal year focus Document Fiscal Year Focus Basis of accounting Basis of Accounting, Policy [Policy Text Block] COMMON EQUITY Shareholders' Equity and Share-Based Payments [Text Block] Total income tax expense, percent Effective Income Tax Rate Reconciliation, Percent Summarized financial data Equity Method Investment, Summarized Financial Information [Abstract] Equity Method Investment, Nonconsolidated Investee [Axis] Equity Method Investment, Nonconsolidated Investee [Axis] Carrying amount Reported Value Measurement [Member] Property and revenue taxes Taxes, Miscellaneous Common shareholders' equity Equity [Abstract] Senior Notes Senior Notes Purchase obligations Purchase Obligation Derivative instruments Derivatives, Policy [Policy Text Block] SEGMENT INFORMATION Segment Reporting Disclosure [Text Block] MGU MGU [Member] Represents details pertaining to Michigan Gas Utilities Corporation, which is also referred to as MGU. Schedule of Goodwill [Table] Goodwill [Table] Fair value measurements Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Statements of equity Roll Forward of Common Stock Outstanding Increase (Decrease) in Stockholders' Equity [Roll Forward] Approved rate increase Public Utilities, Approved Rate Increase (Decrease), Amount Finite-Lived Intangible Assets Finite-Lived Intangible Liabilities Finite-Lived Intangible Assets [Line Items] Purchases Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Purchases Schedule of regulatory assets and reserves for manufactured gas plant sites Other Commitments [Table Text Block] Schedule of net benefit cost (credit) Schedule of Net Benefit Costs [Table Text Block] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Fair Value, Assets and Liabilities Measured on Recurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Net income attributed to common shareholders Net Income (Loss) from Continuing Operations Available to Common Shareholders, Basic Depreciation and amortization Depreciation, Depletion and Amortization 5.65% $300M WE Debentures due 03/15/2056 5.65% $300M WE Debentures due 03/15/2056 [Member] 5.65% $300M WE Debentures due 03/15/2056 Transportation Transportation customers [Member] Represents customers from a sector of the economy consisting of companies who purchase natural gas from a third party, but still transport the natural gas through our distribution systems. Forward Contract Indexed to Equity, Net Settlement, Cash Forward Contract Indexed to Equity, Net Settlement, Cash Amount of cash that would be paid (received) upon net settlement of a forward contract. Materials, supplies, and inventories Total Energy Related Inventory Guarantees with expiration over 3 years Guarantee Obligations Maximum Exposure Expire Over Three Years Represents the maximum potential payments with respect to the entity's guarantees that expire after three years. NumberofAcresSold NumberofAcresSold Number of Acres of real estate sold Dilutive effect of convertible senior notes Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities Credit facility maturing August 2030 Revolving Credit Facility [Member] Present value of minimum lease payments Finance Lease, Liability Arrangement Duration Trading Arrangement Duration Realized gains and losses on derivatives income statement location Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Segments [Axis] Segments [Axis] Other operating revenues Other operating revenues [Member] Represents revenues of the company that have been evaluated under Accounting Standard Update 2014-09 and are not considered revenues from contracts with customers. Such operating revenues include alternative revenues, late payment charges, and lease revenue. Electric - generation Electric Generation Equipment [Member] Local Phone Number Local Phone Number Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Other, net Payment for (Proceeds from) Other Investing Activity Other, net Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Other Item Intangible liabilities Net carrying amount Intangible liabilities Intangible liabilities Forward Contract Indexed to Issuer's Equity, Type [Axis] Forward Contract Indexed to Issuer's Equity, Type [Axis] Assets Assets Assets [Abstract] Credit Facility [Axis] Credit Facility [Axis] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Components of net periodic benefit cost (credit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Debt Instrument [Axis] Debt Instrument [Axis] EMPLOYEE BENEFITS Retirement Benefits [Text Block] FAIR VALUE MEASUREMENTS Fair Value Disclosures [Text Block] Credit Facility [Domain] Credit Facility [Domain] Current derivative liabilities Derivative Liability, Current Percentage of earnings in excess of 40 basis points refunded to customers Percentage of earnings in excess of 40 basis points refunded to customers Percentage of utility earnings in excess of 40 basis points above the utility’s authorized return on equity (ROE) that will be refunded to customers. Interest rate on long-term debt Debt Instrument, Interest Rate, Stated Percentage Investment, Name [Axis] Investment, Name [Axis] Federal excess deferred tax amortization, percent Effective Income Tax Reconciliation Federal Excess Amortization Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to federal excess deferred tax amortization. Steam Steam Rate Request [Member] Represents information relating to steam rates. Land quality Environmental Compliance Obligations Land Quality [Abstract] Environmental Compliance Obligations Land Quality WPS Wisconsin Public Service Corporation [Member] This element represents details pertaining to Wisconsin Public Service Corporation (WPS). Accounts receivable and unbilled revenues, net Accounts Receivable, after Allowance for Credit Loss Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Abstract] Entity registrant name Entity Registrant Name Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Net periodic benefit (credit) cost Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Minimum Megawatts Required for VLCs Minimum Megawatts Required for VLCs Minimum number of megawatts that a customer needs to use to qualify for the Very Large Customer (VLC) tariff. 2023 Rate Order 2023 Rate Order [Member] Impacts from PGL's and NSG's rate orders issued by the ICC in November 2023. Interest expense Interest Expense, Other Illinois Illinois [Member] The Illinois segment includes the natural gas utility operations of North Shore Gas Company and The Peoples Gas Light and Coke Company. Forward equity sale contracts Forward equity sale contracts [Member] Forward equity sale contracts Regulated Operations [Abstract] Regulated Operations [Abstract] Earnings sharing mechanisms Earnings Sharing Mechanisms [Member] Rate action of a regulator resulting in the capitalization or accrual of earnings that have to be returned to customers due to the company's earnings sharing mechanisms. New limit for particulate matter published in the EPA's 2024 Amendments, in pounds per million british thermal unit New Limit for Particulate Matter Published in the EPA's Final Rule New Limit for Particulate Matter Published in the EPA's Final Rule 5.10% $400M WE Debentures due 06/15/2036 5.10% $400M WE Debentures due 06/15/2036 [Member] 5.10% $400M WE Debentures due 06/15/2036 Interest cost Defined Benefit Plan, Interest Cost Restricted shares granted, weighted-average grant date fair value Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Tax credits, percent Effective Income Tax Rate Reconciliation, Tax Credit, Percent [Abstract] Schedule of intangible liabilities obtained through acquisitions by WECI Schedule of Finite-Lived Intangible Assets [Table Text Block] Restatement Determination Date: Restatement Determination Date [Axis] Requested Rate Increase (Decrease), Percentage Public Utilities, Requested Rate Increase (Decrease), Percentage Amortization of revenue intangibles Amortization of revenue intangibles [Member] Revenues associated with the amortization of intangible assets and liabilities, which relate to PPAs and a proxy revenue swap. Non-Utility Energy Infrastructure Non-Utility Energy Infrastructure [Member] The non-utility energy infrastructure segment includes We Power, which owns and leases generating facilities to WE, and Bluewater, which owns underground natural gas storage facilities in Michigan. It also includes WEC Infrastructure LLC, which holds our ownership interest in renewable generating facilities. Cost of natural gas sold Cost of natural gas sold Cost of natural gas sold Capital contributions from noncontrolling interest Noncontrolling Interest, Increase from Subsidiary Equity Issuance Other, net Proceeds from (Payment for) Other Financing Activity Equity method investments excluding transmission affiliates Nonconsolidated Investees, Other [Member] Samson I Solar Energy Center and Delilah Solar Energy Samson I Solar Energy Center LLC and Delilah Solar Energy LLC [Member] Samson I Solar Energy Center LLC and Delilah Solar Energy LLC are commercially operational solar generating facilities located in Lamar County, Texas. Regulatory Asset [Axis] Regulatory Asset [Axis] Name Trading Arrangement, Individual Name Number of option payments Number of option payments Number of option payments made for exclusive rights to purchase Schedule of Short-term Debt [Table] Short-Term Debt [Table] Schedule of Forward Contracts Indexed to Issuer's Equity Schedule of Forward Contracts Indexed to Issuer's Equity [Table Text Block] WEC 4.75% Senior Notes $400M due January 15, 2028 WEC 4.75% Senior Notes $400M due January 15, 2028 [Member] WEC 4.75% Senior Notes $400M due January 15, 2028 Notional volumes Notional Disclosures [Abstract] Preferred stock of subsidiary Preferred Stock [Member] Decrease to prior rate request Increase (decrease) to prior rate request Amount of increase (decrease) to public utility's previously requested rate increase (decrease) with a regulatory agency. Name Awards Close in Time to MNPI Disclosures, Individual Name Other long-term assets (restricted cash) Restricted cash included in other long-term assets Restricted Cash, Noncurrent 2026 2026 [Member] 2026 Physical Settlement Physical Settlement [Member] Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Regulatory assets (June 30, 2026 and December 31, 2025 include $63.6 and $67.5, respectively, related to WEPCo Environmental Trust) Regulatory assets Regulatory Asset, Noncurrent Schedule of estimated notional volumes and realized gains and losses Derivative Instruments, Realized Gain (Loss) and Notional Volumes [Table Text Block] Tabular disclosure of the amount of the realized gain (loss) and notional volumes for derivative instruments not designated as hedging instruments. Acquisitions Asset Acquisition [Line Items] Asset Acquisition [Line Items] Credit Loss [Abstract] Credit Loss [Abstract] Securitization of environmental control costs related to Pleasant Prairie power plant Securitized Regulatory Asset Carrying value of the regulatory asset that represents capitalized costs that have been or will be securitized (financed with debt) and are expected to be recoverable through a charge approved by a regulator. Types of Other Operating Revenues [Axis] Types of Other Operating Revenues [Axis] Represents different types of other operating revenues Segments [Domain] Segments [Domain] Income Statement Location [Axis] Statement of Income Location, Balance [Axis] Long-term assets Noncurrent assets Assets, Noncurrent Available capacity under existing credit facility Line of Credit Facility, Remaining Borrowing Capacity Schedule of summarized balance sheet data for ATC Schedule Of Equity Method Investments Summarized Balance Sheet Data [Table Text Block] Tabular disclosure of summarized balance sheet data related to significant equity method investments. Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Materials, supplies, and inventories Increase (Decrease) in Inventories Maple Flats Maple Flats [Member] Maple Flats Solar LLC Derivative assets Derivative Asset [Abstract] Long-term assets Assets, Noncurrent [Abstract] Return on equity in excess of first 15 basis points above authorized amount (as a percent) Return on equity in excess of first 15 basis points above authorized amount (as a percent) Return on equity (ROE) in excess of the first 15 basis points above the authorized amount, for which a percentage will be returned to customers. Cash collateral received Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash Not Offset Other, percent Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent Property, plant, and equipment, accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment ATC American Transmission Company LLC American Transmission Company LLC [Member] Information related to American Transmission Company, LLC (ATC), a for-profit, transmission only company. ATC owns, maintains, monitors, and operates electric transmission assets. Preferred stock of subsidiary Preferred Stock, Value, Issued Amount of net accounts receivable with regulatory protections Amount of net accounts receivable with regulatory protections Amount of net accounts receivable and unbilled revenues with regulatory protections in place to mitigate the exposure to credit losses AFUDC-Equity, amount Income Tax Reconciliation Allowance For Funds Used During Construction Capitalized Cost Of Equity Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to the equity portion of allowance for funds used during construction. All Executive Categories All Executive Categories [Member] Common stock – $0.01 par value; 650,000,000 shares authorized; 325,849,383 and $325,461,519 shares outstanding, respectively Common Stock, Value, Issued Finance lease right of use asset Finance Lease, Right-of-Use Asset, after Accumulated Amortization Schedule of convertible debt Convertible Debt [Table Text Block] Equity income in transmission affiliates, net of distributions Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Commitments and contingencies (Note 22) Commitments and Contingencies Minimum number of Bespoke Resources Minimum number of Bespoke Resources Minimum number of Bespoke Resources (e.g. renewable generating facility, battery storage, or natural gas unit) that a customer is required to subscribe to. Cash acquired Cash Acquired from Acquisition Materials and supplies Inventory, Raw Materials and Supplies, Net of Reserves Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Operating expense loans Loans Payable [Member] Income statement impact of amortizing deferred tax benefits Income Statement Impact Of Amortizing Protected Tax Benefits The income statement impact of amortizing protected deferred tax benefits and returning them to customers in compliance with normalization requirements. Plant retirement related items Stranded Costs [Member] Noncontrolling interests Noncontrolling Interest [Member] Equity method investments Equity Method Investments [Policy Text Block] Equity method investment, ownership interest (as a percent) Ownership interest (as a percent) Equity Method Investment, Ownership Percentage NEW ACCOUNTING PRONOUNCEMENTS Accounting Standards Update and Change in Accounting Principle [Text Block] Short-term borrowings Short-Term Debt [Line Items] Current derivative assets balance sheet location Derivative Asset, Current, Statement of Financial Position [Extensible Enumeration] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Dilutive effect of forward equity sales contracts Incremental Common Shares Attributable to Dilutive Effect of Equity Forward Agreements Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Hedging Designation [Axis] Hedging Designation [Axis] Spectrum frequencies Operating and Broadcast Rights [Member] Energy costs recoverable through rate adjustments Energy Costs Recoverable Through Rate Adjustments [Member] Rate action of a regulatory resulting in capitalization or accrual of the under-collection of energy costs that will be collected from customers in the future. OTHER INCOME, NET Other Nonoperating Income and Expense [Text Block] Guarantees expiring in less than 1 year Guarantee Obligations Maximum Exposure Expire Less Than One Year Represents the maximum potential payments with respect to the entity's guarantees that expire in less than a year. Electric Transmission Electric Transmission Segment [Member] The electric transmission segment includes our approximate 60% ownership interest in American Transmission Company, LLC (ATC) and our approximate 75% ownership interest in ATC Holdco LLC (ATC Holdco). Net amount Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Number of derivative instruments Derivative, Number of Instruments Held Derivative Contract [Domain] Derivative Contract [Domain] Issuance of common stock, net Proceeds from Issuance of Common Stock Return on equity in excess of authorized amount (as a percent) Return on equity in excess of authorized amount (as a percent) Return on equity (ROE) in excess of authorized amount, for which the additional earnings will be retained by the utility. All Individuals All Individuals [Member] Long-Term Debt, Type [Domain] Long-Term Debt, Type [Domain] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Capital expenditures Payments to Acquire Property, Plant, and Equipment Name Forgone Recovery, Individual Name Regulatory Agency [Domain] Regulatory Agency [Domain] 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] Intersegment revenues Intersegment Transactions [Member] Transactions with other operating units of the same entity. Provision for credit losses deferred for future recovery or refund Increase (Decrease) in Regulatory Assets and Liabilities Other guarantees Guarantee Type, Other [Member] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Schedule of Finite-Lived Intangible Liabilities [Table] Intangible Asset, Finite-Lived [Table] Revolving credit facilities Line of Credit Facility [Line Items] Leases Lessee, Lease, Description [Line Items] Derivative liabilities Derivative Liability [Abstract] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Commercial and industrial Commercial and Industrial Customer [Member] Represents customers of a sector of the economy consisting of companies engaged in commercial and industrial business activities. Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Title of 12(b) Security Title of 12(b) Security Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Weston Unit 4 Weston Unit 4 [Member] Weston Unit 4 Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Estimated future employer contributions for the remainder of the year Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year Other, amount Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount Environmental remediation liabilities Accrued Environmental Loss Contingencies, Noncurrent Capacity of additional coal-fired generation to be retired by the end of 2031, in megawatts Fossil-fueled Generation Capacity To Be Retired by 2031 The capacity, in megawatts, of fossil-fueled generation capacity to be retired by the end of 2031 Other expense Other expense, net Nonoperating Income (Expense) Short-term Debt, Type [Axis] Short-Term Debt, Type [Axis] PTCs, net, percent Effective Income Tax Rate Reconciliation, Tax Credit, Energy-Related, Percent Thereafter Finance Lease, Liability, to be Paid, after Year Five 2028 Rates 2028 2028 Rates [Member] 2028 Rates Award Timing Disclosures [Line Items] Maximum aggregate sales of common stock through ATM Program Maximum aggregate sales of common stock through ATM Program Maximum aggregate sales price of common stock that can be sold through an at-the-market-offering program. Schedule of inventory Schedule of Inventory, Current [Table Text Block] Service cost Defined Benefit Plan, Service Cost Measurement Frequency [Domain] Measurement Frequency [Domain] Recoveries of amounts previously written off Accounts Receivable, Allowance for Credit Loss, Recovery Net income Net Income (Loss) Attributable to Parent Equity Method Investment, Nonconsolidated Investee [Domain] Equity Method Investment, Nonconsolidated Investee [Domain] Net book value of plant to be retired Public Utilities, Property, Plant and Equipment, Net Long-term liabilities Liabilities, Noncurrent [Abstract] Schedule of effective income tax rate reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Other, net, percent Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Segment information Segment Reporting Information [Line Items] Other operating revenues Revenue Not from Contract with Customer Adoption Date Trading Arrangement Adoption Date Balance sheet impact - forward contracts Balance sheet impact - forward contracts Balance sheet impact of forward contracts prior to settlement External revenues External Revenues [Member] External revenues represents transactions with external parties. Reconciling Eliminations Consolidation, Eliminations [Member] Wisconsin Wisconsin taxing jurisdication [Member] This represents the income tax jurisdiction representing the stare of Wisconsin. Customer [Axis] Customer [Axis] Operating income Operating Income (Loss) Retained earnings Retained Earnings (Accumulated Deficit) Energy costs refundable through rate adjustments Energy Costs Refundable Through Rate Adjustments [Member] Rate action of a regulator resulting in capitalization or accrual of the over-collection of energy costs that will be refunded to customers in the future. 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] Transferred over time Transferred over Time [Member] Natural gas contracts Commodity Contract Natural Gas [Member] Derivative instrument whose primary underlying risk is tied to the commodity price of natural gas. Subsequent Event Type [Domain] Subsequent Event Type [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] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Q1 2026 Forward Sale Contracts Q1 2026 Forward Sale Contracts [Member] Q1 2026 Forward Sale Contracts Statement [Table] Statement [Table] Other income, net Other Nonoperating Income (Expense) O2026Q3Dividends [Member] O2026Q3Dividends [Member] Q3 2026 ordinary quarterly dividend Reconciliation to cash provided by operating activities Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Public Service Commission of Wisconsin Public Service Commission of Wisconsin [Member] Represents the Public Service Commission of Wisconsin (PSCW), which regulates the operations of Wisconsin Public Service Corporation (WPS). Financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Liabilities accrued for software licensing agreements Liabilities Accrued For Software Licensing Agreements Future cash outflow to pay for software licensing agreements already signed and considered to be a noncash investing or financing activity. Settlement alternatives [Domain] Settlement alternatives [Domain] Settlement alternatives [Domain] 2027 capital investments planned under PRP 2027 capital investments planned under PRP 2027 capital investments planned under PGL's Pipe Replacement Program Finance lease obligations Long-term lease liabilities Finance Lease, Liability, Noncurrent GENERAL INFORMATION Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Repayment of long-term debt Repayments of Unsecured Debt All Adjustments to Compensation All Adjustments to Compensation [Member] Amendment flag Amendment Flag Other Postretirement Benefits Other Postretirement Benefits Plan [Member] Termination Date Trading Arrangement Termination Date Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Dividends Payable [Table] Dividends Payable [Table] Capacity of generation unit Capacity Of Generation Unit The capacity, in megawatts, of a generation unit. Basic (in shares) Weighted average basic shares outstanding Weighted Average Number of Shares Outstanding, Basic SUPPLEMENTAL CASH FLOW INFORMATION Cash Flow, Supplemental Disclosures [Text Block] Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Gross amount recognized on the balance sheet Derivative Asset, Gross Asset Including Not Subject to Master Netting Arrangement Segment Reporting [Abstract] Segment Reporting [Abstract] Amortization to be recorded in the next five years Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Percent of net accounts receivable with regulatory protections Percent of net accounts receivable with regulatory protections Percent of net accounts receivable and unbilled revenues with regulatory protections in place to mitigate the exposure to credit losses Debt Disclosure [Abstract] LEASES Lessee Finance and Operating Leases [Text Block] The entire disclosure for finance and operating leases of a lessee. Includes, but is not limited to, a description of the lessee's finance and operating leases and a maturity analysis of the lessee's finance and operating lease liabilities. Write-offs charged against the allowance Accounts Receivable, Allowance for Credit Loss, Writeoff Accounts receivable and unbilled revenues Accounts Receivable, before Allowance for Credit Loss Offsetting derivative liabilities Offsetting Derivative Liabilities [Abstract] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Approved common equity component average (as a percent) Public Utilities, Approved Equity Capital Structure, Percentage Stock-based compensation Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Consolidated Entities [Axis] Consolidated Entities [Axis] Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Axis] Stock options granted Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross 2026 Rate Application 2026 Rate Application [Member] 2026 Rate Application NSG NSG [Member] North Shore Gas Company Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Total regulatory assets Regulatory assets Regulatory Asset Types of Non-Utility Operating Revenues [Axis] Types of Non-Utility Operating Revenues [Axis] Disaggregates non-utility operating revenues. Insider Trading Arrangements [Line Items] Wisconsin WisconsinSegment [Member] The Wisconsin segment includes the electric and natural gas utility operations of Wisconsin Electric Power Company, Wisconsin Public Service Corporation, Wisconsin Gas LLC, and Upper Michigan Energy Resources Corporation. Large commercial and industrial Large commercial and industrial customers [Member] Represents customers of a sector of the economy consisting of companies engaged in large commercial and industrial activities Other current liabilities Regulatory Liability, Current Settlements Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements 2031 Finance Lease, Liability, to be Paid, Year Five Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Joint plant ownership percentage Jointly Owned Utility Plant, Proportionate Ownership Share Trade name Trademarks and Trade Names [Member] Refund period Refund period Period of time over which refunds are made Unamortized debt issuance costs Unamortized Debt Issuance Expense Consolidation Items [Axis] Consolidation Items [Axis] Natural gas in storage Energy Related Inventory, Natural Gas in Storage Decrease in receivables related to property damage insurance proceeds Receivable Increase Decrease Insurance Proceeds Property Damage Increase (decrease) in the receivables related to insurance proceeds for property damage considered to be a noncash investing or financing activity. Lease [Axis] Counterparty Name [Axis] Renegade Solar Project Renegade Solar Project [Member] Renegade solar generating facility Environmental remediation costs Environmental Restoration Costs [Member] Common shareholders' equity Total Common Shareholders' Equity Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. PPAs Customer Contracts [Member] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Non-NEOs Non-NEOs [Member]