Guarantees Guarantor Obligations [Line Items] Statistical Measurement [Domain] Statistical Measurement [Domain] 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] Related Party Transaction [Axis] Related Party Transaction [Axis] 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] Earnings from equity method investments Income (Loss) from Equity Method Investments Tabular List, Table Tabular List [Table Text Block] Leases [Abstract] Leases [Abstract] Income Taxes [Table] Income Taxes [Table] Detailed information about the entity's income taxes. Other prepayments Increase (Decrease) in Prepaid Expenses, Other Fuel and purchased power Fuel And Purchased Power Costs Fuel and purchased power costs incurred that are directly related to goods produced and sold and services rendered during the reporting period. Accounts payable Increase (Decrease) in Accounts Payable Schedule of carrying value and fair value of financial instruments not recorded at fair value Fair Value, by Balance Sheet Grouping [Table Text Block] Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Capacity of coal-fired generation retired, in megawatts Coal Generation Capacity Retired The capacity, in megawatts, of coal generation retired since the beginning of 2018 Measurement Basis [Axis] Measurement Basis [Axis] Adjustment to Compensation: Adjustment to Compensation [Axis] Schedule of revolving credit facility and remaining available capacity Schedule of Line of Credit Facilities [Table Text Block] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Commercial paper Commercial Paper [Member] 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 information related to reportable segments Schedule of Segment Reporting Information, by Segment [Table Text Block] Inventory Disclosure [Abstract] Inventory Disclosure [Abstract] Cash collateral posted Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Offset 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. 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 short-term debt Proceeds from (Repayments of) Short-Term Debt, Maturing in Three Months or Less Weighted-average interest rate during the period Short-Term Debt, Weighted Average Interest Rate, over Time 2029 Finance Lease, Liability, to be Paid, Year Three Rental revenues Leases [Member] Represents revenues from leases. Employee Stock Option Share-Based Payment Arrangement, Option [Member] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Prepaid taxes Prepaid Taxes Statutory rate reconciliation, percent Effective Income Tax Rate Reconciliation, Percent [Abstract] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Accounts and Financing Receivables [Table] Balance Balance Equity, Attributable to Parent Measurement Frequency [Axis] Measurement Frequency [Axis] Insider Trading Policies and Procedures [Line Items] Public Utilities, Regulatory Proceeding [Domain] Public Utilities, Regulatory Proceeding [Domain] Common stock, shares authorized Common Stock, Shares Authorized Hedging Designation [Domain] Hedging Designation [Domain] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Current assets Assets, Current [Abstract] Total liabilities and equity Liabilities and Equity Other current liabilities Increase (Decrease) in Other Current Liabilities Fair value measurements on a recurring basis Fair Value, Recurring [Member] 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 Liabilities and Shareholders' Equity Liabilities and Equity [Abstract] Cover [Abstract] Cover [Abstract] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Maximum Maximum [Member] Offsetting derivative assets Offsetting Derivative Assets [Abstract] Long-term derivative assets balance sheet location Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration] Fossil fuel Energy Related Inventory, Other Fossil Fuel Electric transmission costs Electric Transmission Costs [Member] Rate action of a regulator resulting in capitalization or accrual of electric transmission costs. Long-term Debt, Unclassified [Abstract] Long-Term Debt, Unclassified [Abstract] Capital expenditures Segment, Expenditure, Addition to Long-Lived Assets Accounting policies Accounting Policies [Abstract] Guarantees [Abstract] Guarantees [Abstract] Asset Acquisition [Text Block] Asset Acquisition [Text Block] Long-term derivative liabilities balance sheet location Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] 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] Reimbursement for ATC's transmission infrastructure upgrades Proceeds from Collection of Advance to Affiliate Non-service components of net periodic benefit costs Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component Realized gains (losses) Derivative, Gain (Loss) on Derivative, Net [Abstract] Cost of natural gas sold Fuel Costs Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Pay vs Performance Disclosure [Line Items] Retirement Benefits [Abstract] Retirement Benefits [Abstract] Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Liabilities Liabilities [Abstract] Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Income before income taxes Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Other Other Liabilities, Noncurrent 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] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Schedule of additional information regarding the statements of cash flows Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Company Selected Measure Amount Company Selected Measure Amount 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] Name Measure Name Letter of credit Letter of Credit [Member] Average amount outstanding during the period Short-Term Debt, Average Outstanding Amount Number Of Customers Number Of Customers The number of customers served by the entity. 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] Sales Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Sales Deferred income taxes Deferred Income Tax Liabilities, Net Document fiscal period focus Document Fiscal Period Focus Derivative instruments Derivatives, Fair Value [Line Items] Mercury and Air Toxics Standards Mercury and Air Toxics Standards [Member] Represents information related to the mercury and air toxics standards [Member] Award Timing Method Award Timing Method [Text Block] Award Type Award Type [Axis] Gross amount not offset on balance sheet Derivative Liability, Subject to Master Netting Arrangement, Gross Asset and Collateral, Right to Reclaim Cash, Offset Long-term debt Long-Term Debt Total assets Total assets Assets Income tax related items Deferred Income Tax Charge [Member] 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] 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] AROs Asset Retirement Obligation Costs [Member] Operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Weighted-average discount rate finance lease Finance Lease, Weighted Average Discount Rate, Percent MATERIALS, SUPPLIES, AND INVENTORIES Inventory Disclosure [Text Block] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Credit losses Credit Loss, Financial Instrument [Policy Text Block] Other utility Other utility [Member] Represents a customer whose revenues are a part of multiple customer classes combined or not specifically identifiable to any one customer. 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 2027 Finance Lease, Liability, to be Paid, Year One Entity common stock, shares outstanding Entity Common Stock, Shares Outstanding Other adjustments, amount Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount [Abstract] 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] 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 Gains (losses) Derivative, Gain (Loss) on Derivative, Net 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] Equity method investments Equity Method Investments Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Indefinite-lived intangible assets Indefinite-Lived Intangible Assets (Excluding Goodwill) Schedule of rate requests Public Utilities General Disclosures [Table Text Block] 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 Related party Related Party [Member] Payment of dividends to parent Payments of Distributions to Affiliates Common stock, shares outstanding Common Stock, Shares, Outstanding REGULATORY ASSETS AND LIABILITIES Schedule of Regulatory Assets and Liabilities [Text Block] Indefinite-Lived Intangible Assets Intangible Asset, Acquired, Indefinite-Lived [Line Items] Provision for credit losses Accounts Receivable, Credit Loss Expense (Reversal) PEO PEO [Member] Operating revenues disaggregated by revenue source Disaggregation of Revenue [Table Text Block] Interest income Investment Income, Interest Significant non-cash investing and financing transactions Noncash Investing and Financing Items [Abstract] 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] Change in – Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] 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] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [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 Total operating expenses Utilities Operating Expense Climate Change Climate Change [Member] Represents information related to climate change as defined by the EPA's Clean Power Plan. 2027 and 2028 Rate Case 2027 and 2028 Rate Case [Member] 2027 and 2028 Rate Case Retained earnings Retained Earnings [Member] Income Tax Authority [Axis] Income Tax Jurisdiction [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement [Abstract] Income Statement [Abstract] Derivative assets Total derivative assets Derivative Asset Income tax expense Total income tax expense, amount Income Tax Expense (Benefit) 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. Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Derivatives designated as hedging instruments Designated as Hedging Instrument [Member] Leases acquired during Q2 2026 Leases acquired during Q2 2026 [Member] Leases acquired during Q2 2026 Product and Service [Domain] Product and Service [Domain] 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). Total common shareholder's equity Parent [Member] 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] Other current assets Increase (Decrease) in Other Current Assets AFUDC-Equity Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity 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] City Area Code City Area Code Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Other, net - income 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] Other, net, amount Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Lessee Disclosure [Abstract] Lessee Disclosure [Abstract] Requested Rate Increase, Amount Public Utilities, Requested Rate Increase (Decrease), Amount Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] 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. 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. Net cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Changes to the carrying amount of goodwill Goodwill, Period Increase (Decrease) Income Taxes Effective Income Tax Rate Reconciliation [Table] Amortization of net actuarial loss Defined Benefit Plan, Amortization of Gain (Loss) Income taxes Effective Income Tax Rate Reconciliation [Line Items] Goodwill Goodwill Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] PEO Total Compensation Amount PEO Total Compensation Amount 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. Bluewater Natural Gas Holding, LLC Bluewater [Member] Rate action of a regulator resulting in capitalization or accrual of the difference between actual storage costs and those included in rates. 2030 Finance Lease, Liability, to be Paid, Year Four Prepaid taxes Increase (Decrease) in Prepaid Taxes Equity Components [Axis] Equity Components [Axis] 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 that the EPA Reverted Back to with the Repeal of the 2024 Amendments effective April 27, 2026 Represents the new level of particulate matter in pounds per million british thermal units that the EPA reverted back to with the repeal of the 2024 amendments effective April 27, 2026 Standby letters of credit Standby Letters of Credit [Member] Asset Acquisition [Abstract] Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Number of reportable segments Number of Reportable Segments Utility segment Utility Segment [Member] The utility segment includes activities related to regulated utility operations. Supplemental Cash Flow Information [Abstract] 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 Total retail 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 Other Performance Measure, Amount Other Performance Measure, Amount Regulatory liabilities Regulatory Liability, Noncurrent Entity Address, State or Province Entity Address, State or Province Fair value measurements Fair Value Measurement, Policy [Policy Text Block] Current liabilities Liabilities, Current Statutory rate reconciliation, amount Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract] Deferred ITCs Accumulated Deferred Investment Tax Credit Derivative Instrument [Axis] Derivative Instrument [Axis] Individual: Individual [Axis] Financial instruments Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Income Tax Authority [Domain] Income Tax Jurisdiction [Domain] LEASES Lessee, Finance Leases [Text Block] 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] Other Other Assets, Current Additional paid in capital Additional Paid in Capital, Common Stock Net cash used in investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation 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] Long-term derivative assets Derivative Asset, Noncurrent Cash paid for interest, net of amount capitalized Interest Paid, Excluding Capitalized Interest, Operating Activity 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] Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Natural gas Natural Gas, US Regulated [Member] 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 Total income tax expense, percent Effective Income Tax Rate Reconciliation, Percent Entity Interactive Data Current Entity Interactive Data Current Cash collateral Derivative, Collateral [Abstract] Other Other Operating Segment [Member] Carrying amount Reported Value Measurement [Member] Property and revenue taxes Taxes, Miscellaneous Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Equity [Abstract] Equity [Abstract] Purchase obligations Purchase Obligation Derivative instruments Derivatives, Policy [Policy Text Block] SEGMENT INFORMATION Segment Reporting Disclosure [Text Block] Fair value measurements Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] 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. Equity contribution from parent Proceeds from Contributions from Parent Statements of equity Increase (Decrease) in Stockholders' Equity [Roll Forward] 2027 Rates 2027 Rates [Member] 2027 Rates Purchases Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Purchases Schedule of regulatory assets and reserves related to 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, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] 2028 Finance Lease, Liability, to be Paid, Year Two Short-term debt Commercial paper outstanding Commercial Paper Depreciation and amortization Depreciation and amortization Depreciation, Depletion and Amortization 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. Other Other Assets, Noncurrent 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 External revenues Revenues Materials, supplies, and inventories Total Energy Related Inventory 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] 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. Removal costs Removal Costs [Member] Regulatory liabilities Regulatory Liability [Line Items] 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 Revolving credit facility maturing August 2030 Revolving Credit Facility [Member] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan [Table] Present value of minimum lease payments Finance Lease, Liability Arrangement Duration Trading Arrangement Duration Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Realized gains and losses on derivatives income statement location Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] 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] 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. Exercise Price Award Exercise Price Entity filer category Entity Filer Category Local Phone Number Local Phone Number Notional volumes Derivative, Nonmonetary Notional Amount, Energy Measure Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] United States federal statutory income tax rate, percent Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent 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 Assets Assets [Abstract] Long-term debt Long-Term Debt, Excluding Current Maturities Credit Facility [Axis] Credit Facility [Axis] Nonrelated party Nonrelated Party [Member] 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] Common shareholder's equity Equity, Attributable to Parent [Abstract] Current derivative liabilities Derivative Liability, Current 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] Schedule of Acquired Indefinite-Lived Intangible Assets by Major Class [Table] Schedule of Acquired Indefinite-Lived Intangible Assets by Major Class [Table] Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Debt instrument stated interest rate percentage Debt Instrument, Interest Rate, Stated Percentage Accounts receivable and unbilled revenues, reserves Accounts Receivable, Allowance for Credit Loss, Current 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. 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) Land quality Environmental Compliance Obligations Land Quality [Abstract] Environmental Compliance Obligations Land Quality Fair Value as of Grant Date Award Grant Date Fair Value Accounts receivable and unbilled revenues, net Accounts Receivable, after Allowance for Credit Loss Entity registrant name Entity Registrant Name FTRs Commodity Contract Transmission Congestion Rights [Member] Derivative instrument used to manage electric transmission congestion costs. Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Net periodic benefit credit Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Schedule of Other Income, Net Schedule of Other Nonoperating Income (Expense) [Table Text Block] Interest expense Interest Expense, Other Minimum future commitments for purchase obligations Unconditional Purchase Obligations (Excluding Capital Stock Redemptions) [Abstract] Regulated Operations [Abstract] Regulated Operations [Abstract] Document Quarterly Report Document Quarterly Report Deferred income taxes and ITCs, net Deferred Income Taxes and Tax Credits 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] 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 Previous limit for 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 Leases [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 Interest cost Defined Benefit Plan, Interest Cost Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Tax credits, percent Effective Income Tax Rate Reconciliation, Tax Credit, Percent [Abstract] Residential Residential customer [Member] Represents customers of a sector of the economy consisting of residential dwellings. Restatement Determination Date: Restatement Determination Date [Axis] Requested Rate Increase, Percentage Public Utilities, Requested Rate Increase (Decrease), Percentage Non-PEO NEO Non-PEO NEO [Member] Letters of credit issued inside credit facility Letters of Credit Outstanding, Amount Other, net Proceeds from (Payment for) Other Financing Activity 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. Regulatory Asset [Axis] Regulatory Asset [Axis] Schedule of regulatory liabilities Schedule of Regulatory Liabilities [Table Text Block] Name Trading Arrangement, Individual Name All Award Types Award Type [Domain] Schedule of Short-term Debt [Table] Short-Term Debt [Table] Equity Awards Adjustments Equity Awards Adjustments [Member] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] 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] Notional volumes Notional Disclosures [Abstract] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Fair value Estimate of Fair Value Measurement [Member] Types of Operating Revenues [Domain] Types Of Operating Revenue [Domain] Operating revenue of the company Retirement Plan Type [Domain] Retirement Plan Type [Domain] Rollforward of the allowances for credit losses Accounts Receivable, Allowance for Credit Loss [Table Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Name Awards Close in Time to MNPI Disclosures, Individual Name Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Regulatory assets Regulatory Asset, Noncurrent Asset Acquisition Asset Acquisition [Line Items] Six months ended December 31, 2026 Finance Lease, Liability, to be Paid, Remainder of Fiscal Year Credit Loss [Abstract] Credit Loss [Abstract] Tax credits, amount Effective Income Tax Rate Reconciliation, Tax Credit, Amount [Abstract] Schedule of future minimum lease payments for finance leases Finance Lease, Liability, to be Paid, Maturity [Table Text Block] Previous level of micrograms per cubic meter under 24-hour standard that particulate matter needed to be below Annual Standard for the Particulate Matter NAAQS Represents the annual standard for the particulate matter NAAQS that needs to be below 12 micrograms per cubic meter, while retaining the 24-hour standard. Air quality Environmental Compliance Obligations Air Quality [Abstract] -- None. No documentation exists for this element. -- Types of Other Operating Revenues [Axis] Types of Other Operating Revenues [Axis] Represents different types of other operating revenues Segments [Domain] Segments [Domain] Types of Operating Revenues [Axis] Types of Operating Revenues [Axis] Disaggregates Operating Revenues into different types [Axis] Long-term assets Assets, Noncurrent Available capacity under existing credit facility Line of Credit Facility, Remaining Borrowing Capacity Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Materials, supplies, and inventories Increase (Decrease) in Inventories Other adjustments, percent Effective Income Tax Rate Reconciliation, Other Reconciling Items, Percent [Abstract] 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 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] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Accounts payable Accounts Payable, Current 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 Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] 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 – $4 par value; 32,000,000 shares authorized; 23,896,962 shares issued and outstanding Common Stock, Value, Issued Finance lease right of use asset Finance Lease, Right-of-Use Asset, after Accumulated Amortization COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Current derivative liability balance sheet location Derivative Liability, Current, Statement of Financial Position [Extensible Enumeration] Schedule of Regulatory Assets [Table] Regulated Operation, Regulatory Asset [Table] Weighted-average interest rate on amounts outstanding Short-Term Debt, Weighted Average Interest Rate, at Point in Time Commitments and contingencies (Note 18) Commitments and Contingencies Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Derivative [Table] Derivative [Table] Materials and supplies Inventory, Raw Materials and Supplies, Net of Reserves Proceeds from cash surrender value of life insurance Proceeds from Life Insurance Policy 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 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. Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Other operation and maintenance Other Cost and Expense, Operating Plant retirement related items Stranded Costs [Member] Types of Other Operating Revenues [Domain] Types of Other Operating Revenues [Domain] [Domain] for Represents different types of other operating revenues Long-Term Debt Long-Term Debt [Text Block] Document Transition Report Document Transition Report Equity method investments Equity Method Investments [Policy Text Block] Reconciliation of changes in the 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] NEW ACCOUNTING PRONOUNCEMENTS Accounting Standards Update and Change in Accounting Principle [Text Block] Total minimum lease payments Finance Lease, Liability, to be Paid Underlying Securities Award Underlying Securities Amount Short-term borrowings Short-Term Debt [Line Items] Late payment charges Late payment charges [Member] Represents revenues from late payment charges Equity Component [Domain] Equity Component [Domain] Other, net - expense Other Nonoperating Expense Current derivative assets balance sheet location Derivative Asset, Current, Statement of Financial Position [Extensible Enumeration] Document period end date Document Period End Date PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount INCOME TAXES Income Tax Disclosure [Text Block] 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] 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] Net amount Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction OTHER INCOME, NET Other Nonoperating Income and Expense [Text Block] Document type Document Type Level 3 Fair Value, Inputs, Level 3 [Member] Name Outstanding Recovery, Individual Name Loss Contingencies [Table] Loss Contingencies [Table] Net amount Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Product and Service [Axis] Product and Service [Axis] Accounts receivables Accounts and Other Receivables, Net, Current Number of derivative instruments Derivative, Number of Instruments Held Derivative Contract Type [Domain] Derivative Contract [Domain] Asset Acquisition [Domain] Asset Acquisition [Domain] 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 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] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Capital expenditures Payments to Acquire Property, Plant, and Equipment Name Forgone Recovery, Individual Name Current assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] 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] Electric Electricity, US Regulated [Member] Provision for credit losses deferred for future recovery or refund Increase (Decrease) in Regulatory Assets and Liabilities Regulatory Asset [Domain] Regulatory Asset [Domain] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Current liabilities Liabilities, Current [Abstract] Revolving credit facility Line of Credit Facility [Line Items] Leases Lessee, Lease, Description [Line Items] Derivative liabilities Derivative Liability [Abstract] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] PTCs, net, amount Effective Income Tax Rate Reconciliation, Tax Credit, Energy-Related, Amount Level 1 Fair Value, Inputs, Level 1 [Member] 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. Customer credit balances Deferred Revenue, Current Other, amount Effective Income Tax Rate Reconciliation, Tax Credit, Other, Amount Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Lessee, Lease, Description [Table] Lessee, Lease, Description [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 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 Capacity of additional fossil-fueled 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 State Income Tax Paid, State and Local, after Refund Received Other expense Nonoperating Income (Expense) 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 cash paid (received) for income taxes 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] Short-term Debt, Type [Axis] Short-Term Debt, Type [Axis] 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 PTCs, net, percent Effective Income Tax Rate Reconciliation, Tax Credit, Energy-Related, Percent Total income taxes paid, net Income Taxes Paid, Net Thereafter Finance Lease, Liability, to be Paid, after Year Five 2028 Rates 2028 Rates [Member] 2028 Rates Award Timing Disclosures [Line Items] 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 Schedule of inventory Schedule of Inventory, Current [Table Text Block] Service cost Defined Benefit Plan, Service Cost Measurement Frequency [Domain] Measurement Frequency [Domain] Accrued payroll and benefits Employee-related Liabilities, Current Recoveries of amounts previously written off Accounts Receivable, Allowance for Credit Loss, Recovery Net income Net income Net Income (Loss) Attributable to Parent Expiration Date Trading Arrangement Expiration Date Long-term liabilities Liabilities, Noncurrent [Abstract] Product Information [Line Items] Product Information [Line Items] Schedule of effective income tax rate reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Requested common equity component average (as a percent) Public Utilities, Requested Equity Capital Structure, Percentage 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 Property, plant, and equipment, net of accumulated depreciation and amortization of $2,352.9 and $2,320.2, respectively Property, Plant and Equipment, Net Segment information Segment Reporting Information [Line Items] Other operating revenues Revenue Not from Contract with Customer Adoption Date Trading Arrangement Adoption Date Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Entity Current Reporting Status Entity Current Reporting Status Derivative instruments Derivative [Line Items] Wisconsin jurisdiction exceeded 5% of income taxes paid Wisconsin taxing jurisdication [Member] This represents the income tax jurisdiction representing the stare of Wisconsin. Customer [Axis] Customer [Axis] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Operating income Operating Income (Loss) Retained earnings Retained Earnings (Accumulated Deficit) United States federal statutory income tax rate, amount Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Gross amount not offset on the balance sheet Derivative Liability, Gross Liability Including Not Subject to Master Netting Arrangement 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. 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. Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] 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] Executive Category: Executive Category [Axis] 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. State and local income taxes net of federal tax effect, percent Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Short-term lease liabilities Finance Lease, Liability, Current Issuance of long-term debt Proceeds from Issuance of Long-Term Debt Current fiscal year end date Current Fiscal Year End Date 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] Schedule of gross receivables and related allowances for credit losses Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Amounts refundable to customers Amounts refundable to customers The increase (decrease) during the reporting period in the amount due to customers for certain regulatory liabilities, including amounts refundable for natural gas costs. Statement [Table] Statement [Table] Other income, net Other income, net Other Nonoperating Income (Expense) Derivative liabilities Total derivative liabilities Derivative Liability 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. Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Capacity of generation unit (in megawatts) Capacity of Generation Unit (in megawatts) Capacity of Generation Unit 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] Finance lease obligations Long-term lease liabilities Finance Lease, Liability, Noncurrent Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] GENERAL INFORMATION Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] All Adjustments to Compensation All Adjustments to Compensation [Member] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Amendment flag Amendment Flag Other Postretirement Benefits Other Postretirement Benefits Plan [Member] 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. Termination Date Trading Arrangement Termination Date Net cash provided by (used in) financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Measure: Measure [Axis] SUPPLEMENTAL CASH FLOW INFORMATION Cash Flow, Supplemental Disclosures [Text Block] Cost of sales Cost of Product and Service Sold Gross amount recognized on the balance sheet Derivative Asset, Gross Asset Including Not Subject to Master Netting Arrangement Related Party Transaction [Domain] Related Party Transaction [Domain] Segment Reporting [Abstract] Segment Reporting [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 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 Public Utilities, General Disclosures [Line Items] Public Utilities, General Disclosures [Line Items] Entity Tax Identification Number Entity Tax Identification Number Asset Acquisition [Axis] Asset Acquisition [Axis] 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 Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares issued Common Stock, Shares, Issued Total regulatory liabilities Regulatory liability Regulatory Liability Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Axis] GOODWILL AND INTANGIBLE ASSETS Goodwill and Intangible Assets Disclosure [Text Block] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Regulatory assets Regulatory assets Regulatory Asset Trading Arrangement: Trading Arrangement [Axis] Current derivative assets Derivative Asset, Current Total Shareholder Return Amount Total Shareholder Return Amount Environmental matters Loss Contingencies [Line Items] Insider Trading Arrangements [Line Items] Large commercial and industrial customers 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 Acquisition purchase price, expected Asset Acquisition, Price of Acquisition, Expected Long-term liabilities Liabilities, Noncurrent Settlements Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements Accounts payable related to construction costs Capital Expenditures Incurred but Not yet Paid 2031 Finance Lease, Liability, to be Paid, Year Five Revolving credit facility Line of Credit Facility, Maximum Borrowing Capacity Utility Utility [Member] The utility segment includes our electric and natural gas utility operations. Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Indefinite-Lived Intangible Assets, Major Class Name [Domain] Indefinite-Lived Intangible Assets, Major Class Name [Domain] Operating expenses Operating Expenses [Abstract] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Other Other Liabilities, Current Joint plant ownership percentage Jointly Owned Utility Plant, Proportionate Ownership Share Condensed financial statements Statement [Line Items] Natural gas in storage Energy Related Inventory, Natural Gas in Storage Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Cash and cash equivalents Cash and Cash Equivalent Leases [Axis] Counterparty Name [Axis] Environmental remediation costs Environmental Restoration Costs [Member] Common stock Common Stock [Member] Common shareholder's 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. Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Non-NEOs Non-NEOs [Member] Finance leases Finance Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract] Net change in cash and cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation