Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Electric plant Electricity Generation Plant, Non-Nuclear [Member] Trading Arrangement: Trading Arrangement [Axis] Less accumulated depreciation Public Utilities, Property, Plant and Equipment, Accumulated Depreciation Short-term Debt, Type [Axis] Short-Term Debt, Type [Axis] Document Fiscal Year Focus Document Fiscal Year Focus Adjustment to Compensation, Amount Adjustment to Compensation Amount Alternative and Other [Member] Alternative and Other [Member] Alternative and Other [Member] Customer [Axis] Customer [Axis] Segment Reporting [Abstract] Segment Reporting [Abstract] Common stock — 100 shares authorized of $0.01 par value; 100 shares outstanding at June 30, 2026 and Dec. 31, 2025, respectively Common Stock, Value, Issued Depreciation and amortization Depreciation, Amortization and Accretion, Net Interest charges and other financing costs Interest Expense, Operating and Nonoperating State income taxes, net of federal tax effect (c) Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Benefit Plans and Other Postretirement Benefits Retirement Benefits [Text Block] Restatement Determination Date Restatement Determination Date Return Cash Collateral Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash, Offset Against Derivative Asset Expected return on Plan Assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Derivative Instrument Risk [Axis] Derivative Instrument [Axis] Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Measurement Frequency [Axis] Measurement Frequency [Axis] Property, Plant and Equipment, Net Public Utility Property, Plant, and Equipment [Table Text Block] Industry of Counterparty, Type [Axis] Industry of Counterparty, Type [Axis] Regulatory liabilities Regulatory Liability, Noncurrent Amendment Flag Amendment Flag Consolidated Entities [Axis] Consolidated Entities [Axis] Current liabilities Liabilities, Current [Abstract] Gross Notional Amounts of Commodity Forwards and Options Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Inventory [Axis] Inventory [Axis] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Allowance for funds used during construction — equity Allowance for equity funds used during construction Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity Cost of sales — other Other Cost of Operating Revenue Loss Contingencies [Table] Loss Contingencies [Table] Other comprehensive income Other Comprehensive Income (Loss), Net of Tax [Abstract] Retail Retail Distribution [Member] Retail Distribution [Member] Consolidated Entities [Domain] Consolidated Entities [Domain] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Entity Address, State or Province Entity Address, State or Province Public Utility, Property, Plant and Equipment [Table] Public Utility, Property, Plant and Equipment [Table] PEO Total Compensation Amount PEO Total Compensation Amount Common Stock, Par or Stated Value Per Share Common Stock, Par or Stated Value Per Share Inventories Schedule of Utility Inventory [Table Text Block] Retirement Benefits [Abstract] Retirement Benefits [Abstract] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Commodity contracts designated as cash flow hedges Commodity contracts designated as cash flow hedges Commodity contracts designated as cash flow hedges Regulatory assets Regulatory Asset, Noncurrent Loss Contingencies [Line Items] Loss Contingencies [Line Items] Total current liabilities Liabilities, Current Taxes (other than income taxes) Taxes, Miscellaneous Other Unregulated Operating Revenue Natural gas Regulated Operating Revenue, Gas Regulated Operating Revenue, Gas Short-term Debt, Type [Domain] Short-Term Debt, Type [Domain] Comprehensive income: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Entity Address, City or Town Entity Address, City or Town Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Wholesale, trading and non-trading commodity credit exposure for the most significant counterparties Wholesale, trading and non trading commodity credit exposure for the most significant counterparties Wholesale, trading and non-trading commodity credit exposure for the entity's most significant counterparties. Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Total revenue from contracts with customers Product [Member] Percentage of wholesale, trading and non-trading commodity credit exposure for the most significant counterparties (in hundredths) Percentage of wholesale, trading and non trading commodity credit exposure for the most significant counterparties Percentage of wholesale, trading and non-trading commodity credit exposure for the entity's most significant counterparties. Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Derivative, Nonmonetary Notional amount Derivative, Nonmonetary Notional Amount Level 2 Fair Value, Inputs, Level 2 [Member] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Net current period other comprehensive loss Other Comprehensive Income (Loss), Net of Tax Borrowing limit Line of Credit Facility, Maximum Borrowing Capacity Credit Facility Line of Credit Facility, Maximum Borrowing Capacity Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Xcel Energy Inc. Parent Company [Member] PTCs (a) Effective Income Tax Rate Reconciliation, Tax Credit, Percent Concentration Risk by Type [Axis] Concentration Risk Type [Axis] Contribution of capital by parent Adjustments to Additional Paid in Capital, Other Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Marshall Wildfire Settlement Marshall Wildfire Settlement [Member] Marshall Wildfire Settlement Marshall Settlements Reached Marshall Settlements Reached Marshall Settlements Reached Litigation Case [Axis] Litigation Case [Axis] Accrued property, plant and equipment additions Capital Expenditures Incurred but Not yet Paid Xcel Energy Xcel Energy [Member] Xcel Energy Results from Operations by Reportable Segment Segment Reporting [Table Text Block] Deferred credits and other liabilities Liabilities, Other than Long-Term Debt, Noncurrent [Abstract] Related Party, Type [Axis] Related and Nonrelated Parties [Axis] Total other comprehensive income Total other comprehensive income Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Long-term Debt Long-Term Debt Schedule of Future Commitments under Operating Leases Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] Cost of identified MGP, landfill, or disposal sites under current investigation and/or remediation Cost of identified MGP, landfill, or disposal sites under current investigation and/or remediation Cost of identified MGP, landfill, or disposal sites under current investigation and/or remediation Document Period End Date Document Period End Date Changes in operating assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Net cash used in investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Debt Instrument, Face Amount Debt Instrument, Face Amount Operating expenses Costs and Expenses [Abstract] Netting Derivative Liability, Subject to Master Netting Arrangement, Gross Asset and Collateral, Right to Reclaim Cash, Offset Plant Public Utilities, Property, Plant and Equipment, Generation or Processing Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Electric fuel and purchased power Electric Fuel and Purchased Power Electric Fuel and Purchased Power Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company Consolidation Items [Domain] Consolidation Items [Domain] Generating capacity under long term purchased power agreements (in MW) Generating capacity under long term purchased power agreements Generating capacity under long-term purchased power agreements. Other Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Total contributions to the pension plans during the period Payment for Pension Benefits Operating lease liabilities Less current portion Operating Lease, Liability, Current Accrued interest Interest Payable, Current Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Name Outstanding Recovery, Individual Name Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Document Fiscal Period Focus Document Fiscal Period Focus Effects of regulation Defined Benefit Plan Credits Not Recognized Due To Effects of Regulation The additional amount of credits not recognized in net periodic benefit as reported in the financial statements of the entity due to effects of regulation. Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Commodity Trading Commodity Trading Contract [Member] Derivative instrument whose primary underlying risk is tied to commodity prices. Net periodic benefit cost Defined Benefit Plan Net Benefit Cost (Credit) Recognized Before Regulatory Adjustments The total mount of net periodic benefit cost, before regulatory adjustments, for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain or loss, prior service cost or credit, transition asset or obligation, and gain or loss due to settlements or curtailments, before regulatory adjustments. Derivative, Gross Liability with Cross Default Position, Aggregate Fair Value Derivative, Gross Liability with Cross Default Position, Aggregate Fair Value Derivative, Gross Liability with Cross Default Position, Aggregate Fair Value Depreciation and amortization Utilities Operating Expense, Depreciation and Amortization Utilities Operating Expense, Depreciation and Amortization Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Company Selected Measure Name Company Selected Measure Name Marshall Wildfire litigation Gain (Loss) from Litigation Settlement Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Other Effective Income Tax Rate Reconciliation, Tax Credit, Other, Amount Defined Benefit and Postretirement Items Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Public Utilities, Inventory [Table] Regulated Operation, Inventory [Table] Electric Commodity (in megawatt hours) Electric Commodity [Member] Derivative instrument whose primary underlying risk is tied to electric commodity prices. Other MGP, Landfill, or Disposal Sites Other MGP, Landfill, or Disposal Sites [Member] Credit Facility [Domain] Credit Facility [Domain] Operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Compensation Amount Outstanding Recovery Compensation Amount Dividends payable to parent Dividends Payable, Current Individual: Individual [Axis] Public Utility [Axis] Public Utility [Axis] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Entity Emerging Growth Company Entity Emerging Growth Company Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Accounts, Notes, Loans and Financing Receivable [Line Items] Related Party Transaction [Line Items] Pension and employee benefit obligations Liability, Defined Benefit Plan, Noncurrent Natural Gas Commodity Natural Gas Commodity Contract [Member] Derivative instrument whose primary underlying risk is tied to natural gas commodity prices for cost of natural gas sold and transported as well as electric generation. Line of Credit Facility [Table] Line of Credit Facility [Table] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Accrued unbilled revenues Accrued Unbilled Revenues The amount of fees and other revenue, excluding investment income receivable, earned but not yet received, which were recognized in conformity with revenue recognition criteria based on estimates or specific contractual terms. Commercial Paper Commercial Paper [Member] Interest component of obligation Lessee, Operating Lease, Liability, Undiscounted Excess Amount Derivative instruments designated as fair value hedges Fair Value Hedges, Net Electric Regulated Operating Revenue, Electric Regulated Operating Revenue, Electric Regulated Operating Revenue, Electric Short-term debt Short-Term Debt Derivative Liability, Gross Derivative Liability, Subject to Master Netting Arrangement, before Offset Natural gas plant Natural Gas Processing Plant [Member] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Finance Lease, Liability, Undiscounted Excess Amount Finance Lease, Liability, Undiscounted Excess Amount Award Timing Predetermined Award Timing Predetermined [Flag] Property, plant and equipment, net Public Utilities, Property, Plant and Equipment, Net Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Level 1 Fair Value, Inputs, Level 1 [Member] PTCs (a) Effective Income Tax Rate Reconciliation, Tax Credit, Amount Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Lessee, Operating Lease, Liability, Payments, Due Lessee, Operating Lease, Liability, to be Paid Allowance for funds used during construction — debt Public Utilities, Allowance For Funds Used During Construction, Capitalized Cost Of Debt The component of the allowance for funds used during construction during the period based on an assumed rate of return on debt capital used in financing the construction of regulated assets. Regulated Electric Segment Regulated Electric Segment [Member] Regulated Electric Segment All Executive Categories All Executive Categories [Member] Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Debt Instrument, Fair Value Long-Term Debt, Fair Value Components of Net Periodic Benefit Cost (Credit) Schedule of Net Benefit Costs [Table Text Block] Total interest charges and financing costs Interest and Debt Expense Interest and Debt Expense Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Concentration Risk Type [Domain] Concentration Risk Type [Domain] Demand side management expenses Conservation and Demand Side Management Program Expenses Costs incurred for energy conservation, weatherization and other programs to conserve or manage energy use by customers. Amount of accumulated other comprehensive gains (losses) related to interest rate derivatives expected to be reclassified into earnings within the next twelve months Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Segment Information Segment Reporting [Text Block] Direct advances on the credit facility outstanding Long-Term Line of Credit Dividends paid to parent Payments of Ordinary Dividends, Common Stock Expiration Date Trading Arrangement Expiration Date Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Wholesale Distribution [Member] Wholesale Distribution [Member] Wholesale Distribution [Member] Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Beginning Balance Ending Balance Equity, Including Portion Attributable to Noncontrolling Interest Number of identified MGP sites under current investigation and/or remediation Number of identified MGP, landfill, or disposal sites under current investigation and/or remediation Term of letters of credit (in years) Line of Credit Facility, Expiration Period 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] Internal Investment Grade Internal Investment Grade [Member] Nonrelated Party Nonrelated Party [Member] Affiliated Entity Affiliated Entity [Member] Net benefit cost recognized for financial reporting Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Derivative [Table] Derivative [Table] Common Stock, Shares Authorized Common Stock, Shares Authorized Accounts receivable Increase (Decrease) in Accounts and Other Receivables Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Industry of Counterparty [Domain] Industry of Counterparty [Domain] Revenues Including Intersegment Revenues Revenues Including Intersegment Revenues Revenues Including Intersegment Revenues Series Due June 15, 2036 Series Due June 15, 2036 [Member] Series Due June 15, 2036 Exercise Price Award Exercise Price AFUDC equity Effective Income Tax Rate Reconciliation, AFUDC Equity, Amount Effective Income Tax Rate Reconciliation, AFUDC Equity, Amount Investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Fair Value Measured on a Recurring Basis Fair Value, Recurring [Member] Segment Reporting [Line Items] Segment Reporting [Line Items] Document Quarterly Report Document Quarterly Report Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Segment [Domain] Segments [Domain] Interest Rate Swap Interest Rate Swap [Member] Borrowings and Other Financing Instruments Debt Disclosure [Text Block] Repayments of long-term debt Repayments of Long-Term Debt Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Equity Component [Domain] Equity Component [Domain] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Line of Credit Facility [Abstract] Line of Credit Facility [Abstract] Accounts receivable Accounts Receivable, before Allowance for Credit Loss, Current Total operating expenses Costs and Expenses Adoption Date Trading Arrangement Adoption Date Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Dividends declared to parent Dividends, Common Stock, Cash Total common stockholder's equity Accumulated other comprehensive loss at beginning of period Accumulated other comprehensive loss at end of period Equity, Attributable to Parent Series Due March 13, 2029 Series Due March 13, 2029 [Member] Series Due March 13, 2029 Assets Assets [Abstract] Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Number of most significant counterparties for wholesale, trading and non-trading commodity activities with credit exposure Number of most significant counterparties for wholesale, trading and non-trading commodity activities with credit exposure Number of the entity's most significant counterparties for wholesale, trading and non-trading commodity activities with credit exposure. Accounting Policies [Abstract] Accounting Policies [Abstract] Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Environmental Remediation Site [Axis] Environmental Remediation Site [Axis] Operating Lease, Liability Operating Lease, Liability Insider Trading Policies and Procedures [Line Items] Finance Lease, Liability Finance Lease, Liability Accounts Receivable, Allowance for Credit Loss, Current Accounts Receivable, Allowance for Credit Loss, Current Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Credit Facilities Schedule of Line of Credit Facilities [Table Text Block] Prepayments and other Prepaid Expense and Other Assets, Current Deferred income taxes Deferred Income Tax Expense (Benefit) Selected Balance Sheet Data Supplemental Balance Sheet Disclosures [Text Block] Regulatory assets Regulatory Asset, Current Letter of Credit Letter of Credit [Member] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Entity Central Index Key Entity Central Index Key Components of Net Periodic Benefit Cost (Credit) [Abstract] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Additional paid in capital Additional Paid in Capital, Common Stock All Adjustments to Compensation All Adjustments to Compensation [Member] Other, net Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Other Item Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Net cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Federal statutory rate impact Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Income Statement [Abstract] Income Statement [Abstract] Credit Quality Indicator [Domain] Credit Quality Indicator [Domain] Credit quality indicators related to credit exposure. Document Transition Report Document Transition Report Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Finance Lease, Liability, Noncurrent Finance Lease, Liability, Noncurrent Municipal or Cooperative Entities or Other Utilities [Member] Municipal or Cooperative Entities or Other Utilities [Member] Municipal or Cooperative Entities or Other Utilities [Member] Intersegment Eliminations Intersegment Eliminations [Member] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Other Commitments [Domain] Other Commitments [Domain] City Area Code City Area Code Total minimum obligation Finance Lease, Liability, to be Paid Accumulated Other Comprehensive Income (Loss) Total AOCI Attributable to Parent [Member] Allowance for equity funds used during construction Allowance for Funds Used During Construction, Investing Activities All Individuals All Individuals [Member] Number Of Reportable Segments, Disclosed By Definition, Flag Number Of Reportable Segments, Disclosed By Definition, Flag Number Of Reportable Segments, Disclosed By Definition, Flag cash flow hedge commodity [Member] cash flow hedge commodity [Member] cash flow hedge commodity [Member] Name Forgone Recovery, Individual Name Balance Sheet Related Disclosures [Abstract] Balance Sheet Related Disclosures [Abstract] Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Statement [Line Items] Statement [Line Items] Total assets Assets Other Revenue Other Revenue [Member] Other Revenue [Member] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan [Table] Common and other property Public Utilities, Property, Plant And Equipment, Common And Other Property, Plant And Equipment Public Utilities, Property, Plant And Equipment, Common And Other Property, Plant And Equipment New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Accounting Standards Update and Change in Accounting Principle [Abstract] Total revenues Operating Segments [Member] PEO PEO [Member] Drawn Debt, Long-Term and Short-Term, Combined Amount Finance Lease, Cost Finance Lease, Cost Finance Lease, Cost Other Other Liabilities, Noncurrent Retirement Plan Type [Axis] Retirement Plan Type [Axis] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Retained Earnings Retained Earnings [Member] Operating lease liabilities Operating Lease, Liability, Noncurrent Taxes accrued Taxes Payable, Current Credit Facility Revolving Credit Facility [Member] Other Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent Transmission Services [Member] Transmission Services [Member] Transmission Services [Member] Inventory transfers to property, plant and equipment Inventory transfers to plant, property and equipment Amount of increase (decrease) of plant, property and equipment reclassified from inventory. Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Increase (Decrease) in Stockholder's Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Common Stock, Shares, Outstanding Balance (in shares) Balance (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Carrying Amount and Fair Value of Long-term Debt Fair Value, by Balance Sheet Grouping [Table Text Block] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Entity Current Reporting Status Entity Current Reporting Status Net cash provided by financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Other current assets Increase (Decrease) in Prepaid Expense and Other Assets Pension and other employee benefit obligations Increase (Decrease) in Employee Related Liabilities Litigation Case [Domain] Litigation Case [Domain] Provision for bad debts Provision for Bad Debts Provision for Bad Debts Inventory [Domain] Inventory [Domain] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] Adjustments to reconcile net income to cash provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Revenue from Contracts with Customers Revenue from Contract with Customer, Excluding Assessed Tax Property, plant and equipment, net Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization Financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Commercial and Industrial [Member] Commercial and Industrial Customers [Member] Commercial and Industrial Customers [Member] Available Line of Credit Facility, Remaining Borrowing Capacity Other Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Interest Cost Defined Benefit Plan, Interest Cost Derivative Asset, Net Derivative Asset Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Underlying Securities Award Underlying Securities Amount Revenues Revenue from Contract with Customer [Text Block] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] PPAs Purchased Power Agreements [Member] Purchased Power Agreements [Member] Other current liabilities Increase (Decrease) in Other Current Liabilities Inventories Increase (Decrease) in Inventories State income taxes, net of federal tax effect (c) Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Segment Reporting [Table] Segment Reporting [Table] Regulated Natural Gas Regulated Natural Gas [Member] The operations of the regulated natural gas utility segment consists of the transporting, storing, and distributing natural gas in certain markets serviced by the entity. Credit Quality Indicator [Axis] Credit Quality Indicator [Axis] Information by credit quality indicator. Schedule of Components of Lease Expense Lease, Cost [Table Text Block] Residential Residential Customers [Member] Residential Customers [Member] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Pre-tax gains (losses) recognized during the period in income Derivative, Gain (Loss) on Derivative, Net Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Operating income Operating Income (Loss) Current Fiscal Year End Date Current Fiscal Year End Date Other [Member] Other Customers [Member] Other Customers [Member] Repayments under utility money pool arrangement Repayments Under Utility Money Pool Arrangement Repayments of amounts during the reporting period previously borrowed from the utility money pool borrowing arrangement among approved affiliates. Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Derivative [Line Items] Derivative [Line Items] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Service cost Defined Benefit Plan, Service Cost Repayments of short-term borrowings, net Proceeds from (Repayments of) Short-Term Debt Reclassification of losses to net income, net of tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Measure: Measure [Axis] Regulated Operating Revenue Regulated Operating Revenue Asset retirement obligations Asset Retirement Obligations, Noncurrent Repayments from utility money pool arrangement Repayments From Utility Money Pool Arrangement Repayments received during the reporting period of amounts previously invested into the utility money pool borrowing arrangement among approved affiliates. Other Comprehensive Income Comprehensive Income (Loss) Note [Text Block] Equity Components [Axis] Equity Components [Axis] Product and Service [Domain] Product and Service [Domain] Net regulatory assets and liabilities Increase (Decrease) in Regulatory Assets and Liabilities Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Capitalization Capitalization, Long-Term Debt and Equity [Abstract] Entity Interactive Data Current Entity Interactive Data Current Less current portion Finance Lease, Liability, Current Deferred income taxes Deferred Income Tax Liabilities, Net Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Plant related excess deferred taxes Effective Income Tax Rate Reconciliation, Plant Related Excess Deferred Taxes, Amount Effective Income Tax Rate Reconciliation, Plant Related Excess Deferred Taxes, Amount Entity Small Business Entity Small Business Total property, plant and equipment Public Utilities, Property, Plant and Equipment, Plant in Service Total comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Termination Date Trading Arrangement Termination Date Other Commitments [Axis] Other Commitments [Axis] Other Other Services [Member] Other Services [Member] Utility Plant [Domain] Utility Plant [Domain] Cost of natural gas sold and transported Cost of natural Gas Sold and Transported Cost of natural Gas Sold and Transported Federal statutory rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Other Other Liabilities, Current Other Other Assets, Noncurrent Document Type Document Type Public Utilities, Inventory [Line Items] Public Utilities, Inventory [Line Items] Plant to be retired Public Utilities, Property, Plant And Equipment, Plant To Be Retired Public Utilities, Property, Plant And Equipment, Plant To Be Retired Fair Value as of Grant Date Award Grant Date Fair Value Materials and supplies Supplies [Member] Money Pool Money Pool [Member] Arrangement that allows for short-term investments in and borrowings between the utility subsidiaries. Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Common Stock, Shares Issued, Not Disclosed Common Stock, Shares Issued, Not Disclosed Common Stock, Shares Issued, Not Disclosed Arrangement Duration Trading Arrangement Duration Regulated Natural Gas Segment Regulated Natural Gas Segment [Member] Regulated Natural Gas Segment Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Proceeds from issuance of long-term debt Proceeds from Issuance of Long-Term Debt Local Phone Number Local Phone Number Customer advances Contract with Customer, Liability, Noncurrent Other Postretirement Benefits Plan [Member] Other Postretirement Benefits Plan [Member] Consolidation Items [Axis] Consolidation Items [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Bonds [Member] Bonds [Member] Income before income taxes Income before income taxes (domestic) Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Commitments and contingencies Commitments and Contingencies Total revenues Revenues Average amount outstanding Short-Term Debt, Average Outstanding Amount Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Borrowings under utility money pool arrangement Borrowings Payable Under Utility Money Pool Arrangement Borrowings Payable Under Utility Money Pool Arrangement Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Finance Lease, Right-of-Use Asset, Amortization Finance Lease, Right-of-Use Asset, Amortization Liabilities and Equity Liabilities and Equity [Abstract] Other Commitments [Table] Other Commitments [Table] Derivative Assets and Liabilities Measured at Fair Value on a Recurring Basis by Hierarchy Level Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Inventories Total inventories Inventory, Net All Award Types Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Finance Lease, Interest Expense Finance Lease, Interest Expense Fair Value of Financial Assets and Liabilities Fair Value Disclosures [Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] PEO Name PEO Name Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Schedule of Short-term Debt [Table] Short-Term Debt [Table] Property, Plant and Equipment, Type [Axis] Long-Lived Asset, Class [Axis] Continuing Letter of Credit Agreement Continuing Letter of Credit Agreement [Member] Continuing Letter of Credit Agreement Weighted average interest rate, computed on a daily basis (percentage) Line of Credit Facility, Interest Rate During Period Number of extension you can request Number of extension you can request Number of extension you can request Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Other Commitments [Line Items] Other Commitments [Line Items] Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Plant related excess deferred taxes Effective Income Tax Rate Reconciliation, Plant Related Excess Deferred Taxes, Percent Effective Income Tax Rate Reconciliation, Plant Related Excess Deferred Taxes, Percent Cash, cash equivalents and restricted cash at beginning of period Cash, cash equivalents and restricted cash at end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Accounts payable Increase (Decrease) in Accounts Payable Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] External Credit Rating, Investment Grade [Member] External Credit Rating, Investment Grade [Member] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Inventories Public Utilities, Inventory 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] Derivative instruments in a gross liability position Derivative, Gross Liability Position, Aggregate Fair Value The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a gross liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument. Management's Opinion Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Measurement Frequency [Domain] Measurement Frequency [Domain] Debt Instrument [Axis] Debt Instrument [Axis] Collateral posted related to adequate assurance clauses in derivative contracts Collateral Already Posted Adequate Assurance Clauses Aggregate Fair Value The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features for adequate assurance clauses. Customer [Domain] Customer [Domain] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Total current assets Assets, Current Insider Trading Arrangements [Line Items] Impact of Derivative Activity on Accumulated Other Comprehensive Loss, Regulatory Assets and Liabilities, and Income Derivative Instruments, Gain (Loss) [Table Text Block] Award Type Award Type [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Accounts receivable, net Accounts receivable, net Accounts Receivable, after Allowance for Credit Loss, Current Retained earnings Retained Earnings (Accumulated Deficit) Commodity Trading Commodity Contract [Member] Short-Term Borrowings Schedule of Short-Term Debt [Table Text Block] Product and Service [Axis] Product and Service [Axis] Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Pension Plan [Member] Pension Plan [Member] Short-term Debt [Line Items] Short-Term Debt [Line Items] Common stock Common Stock [Member] Derivative Instruments Gain (Loss) Reclassified To Regulatory Assets And Liabilities Net Derivative Instruments Gain (Loss) Reclassified To Regulatory Assets And Liabilities Net Derivative Instruments Gain (Loss) Reclassified To Regulatory Assets And Liabilities Net Operating Lease, Cost Operating Lease, Cost Borrowings under utility money pool arrangement Borrowings Under Utility Money Pool Arrangement Borrowings made during the reporting period from the utility money pool borrowing arrangement among approved affiliates. Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Regulated Electric Regulated Electric [Member] The core operations of the regulated electric utility segment consists of the generation, transmission, and distribution of electricity. In addition, this segment includes sales for resale and provides wholesale transmission service to other entities. Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member] Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member] Short-term Debt, Weighted Average Interest Rate, at Point in Time Short-Term Debt, Weighted Average Interest Rate, at Point in Time Derivative, Name [Domain] Derivative Contract [Domain] Equity Awards Adjustments Equity Awards Adjustments [Member] Total liabilities and equity Liabilities and Equity Employee Stock Option Share-Based Payment Arrangement, Option [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Construction work in progress Public Utilities, Property, Plant and Equipment, Construction Work in Progress Segments [Axis] Segments [Axis] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Related Party, Type [Domain] Related and Nonrelated Parties [Domain] Accounts Receivable, Net Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Tabular List, Table Tabular List [Table Text Block] Other income, net Other Nonoperating Income (Expense) Name Awards Close in Time to MNPI Disclosures, Individual Name Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Other assets Assets, Noncurrent [Abstract] Operating and maintenance expenses Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses Property, Plant and Equipment, Type [Domain] Long-Lived Asset, Class [Domain] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Natural gas Public Utilities, Inventory, Natural Gas [Member] Capital contributions from parent Contributions from (to) parent The cash inflow from (outflow to) parent as a source of financing that is recorded as additional paid in capital. Investments in utility money pool arrangement Investments In Utility Money Pool Arrangement Investments made during the reporting period into the utility money pool borrowing arrangement among approved affiliates. Adjustment to Compensation: Adjustment to Compensation [Axis] Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Hedging Designation [Domain] Hedging Designation [Domain] Credit Concentration Risk Credit Concentration Risk [Member] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Cash paid for interest (net of amounts capitalized) Interest Paid, Excluding Capitalized Interest, Operating Activity Utility capital/construction expenditures Payments to Acquire Productive Assets Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Hedging Designation [Axis] Hedging Designation [Axis] Credit Facility [Axis] Credit Facility [Axis] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Long-term debt Long-Term Debt and Lease Obligation Maximum amount outstanding Short-Term Debt, Maximum Amount Outstanding During Period Name Measure Name Income Taxes Income Tax Disclosure [Text Block] Accrued unbilled revenues Increase (Decrease) in Accrued Unbilled Revenues Increase (Decrease) in Accrued Unbilled Revenues Accounts payable Accounts Payable, Current Pay vs Performance Disclosure [Line Items] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] All Other Other Operating Segment [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Additional Paid In Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Netting Derivative Asset, Subject to Master Netting Arrangement, Gross Liability and Collateral, Obligation to Return Cash, Offset Alternative revenue and other Revenue Not from Contract with Customer Name Trading Arrangement, Individual Name Cash and Cash Equivalent Cash and Cash Equivalent Company Selected Measure Amount Company Selected Measure Amount Other Derivative Instruments Not Designated as Hedging Instrument [Member] AFUDC equity Effective Income Tax Rate Reconciliation, AFUDC Equity, Percent Effective Income Tax Rate Reconciliation, AFUDC Equity, Percent Schedule of Accounts Receivable [Table] Accounts and Financing Receivables [Table] Current assets Assets, Current [Abstract] Derivative Liability, Net Derivative Liability Non-PEO NEO Non-PEO NEO [Member] Interest charges and financing costs Interest and Debt Expense [Abstract] Entity Address, Address Line One Entity Address, Address Line One Operating lease right-of-use assets Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Income tax (benefit) expense Income tax expense Income Tax Expense (Benefit) Other Effective Income Tax Rate Reconciliation, Other Regulatory Adjustments, Percent Effective Income Tax Rate Reconciliation, Other Regulatory Adjustments, Percent Award Timing Method Award Timing Method [Text Block] 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 Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Fuel Public Utilities, Inventory, Fuel [Member] Derivative Liability, Notional Amount Derivative Liability, Notional Amount Amortization of net loss Defined Benefit Plan, Amortization of Gain (Loss) Accounting Pronouncements Accounting Standards Update and Change in Accounting Principle [Text Block] Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Net income Net income Net Income (Loss) Attributable to Parent Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Balance Sheet Location [Axis] Location, Statement of Financial Position, Balance [Axis] Statement [Table] Statement [Table] Environmental Remediation Site [Domain] Environmental Remediation Site [Domain] Restatement Determination Date: Restatement Determination Date [Axis] Regulatory liabilities Regulatory Liability, Current Other Property, Plant and Equipment, Other Types [Member] Changes in Accumulated Other Comprehensive Loss, Net of Tax Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Other Effective Income Tax Rate Reconciliation, Other Regulatory Adjustments, Amount Effective Income Tax Rate Reconciliation, Other Regulatory Adjustments, Amount Public Utility, Property, Plant and Equipment [Line Items] Public Utility, Property, Plant and Equipment [Line Items] Total deferred credits and other liabilities Liabilities, Other than Long-Term Debt, Noncurrent Total operating revenues Regulated and Unregulated Operating Revenue Derivative Asset, Gross Derivative Asset, Subject to Master Netting Arrangement, before Offset Borrowings and Other Financing Instruments [Abstract] Debt Instruments [Abstract] Total other assets Other Assets, Excluding Property, Plant and Equipment Sum of the carrying amounts as of the balance sheet date of all assets, excluding net property, plant and equipment, that are expected to be realized in cash, sold or consumed after one year or beyond the normal operating cycle, if longer. Operating revenues Revenues [Abstract] Supplemental disclosure of non-cash investing and financing transactions: Other Noncash Investing and Financing Items [Abstract] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block]