Reclassification from AOCI, net of tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Revision of Prior Period [Axis] Revision of Prior Period [Axis] Other deferred credits and other long-term liabilities Other deferred credits and other long-term liabilities Deferred Credits and Other Liabilities, Noncurrent Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Net income (loss) Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Deferred income taxes Deferred Income Tax Assets, Net Long-term debt, gross Long-Term Debt, Gross Unit price contracts Unit Priced Contracts [Member] Unit priced contracts. Impairment of assets and other charges Impairment Of Assets And Other Charges Impairment Of Assets And Other Charges Entity Address, Postal Zip Code Entity Address, Postal Zip Code Redemption value adjustments Redemption value adjustments Redemption value adjustments Noncontrolling Interest, Change in Redemption Value Debt Instrument [Axis] Debt Instrument [Axis] Billed on completed contracts and contracts in progress Billed On Completed Contracts And Contracts In Progress [Member] Billed on completed contracts and contracts in progress. Dividends paid Dividends paid Payments of Ordinary Dividends, Common Stock Schedule of Common Stock Activity Schedule Of Common Stock Activity [Table Text Block] Schedule Of Common Stock Activity [Table Text Block] Credit facility maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Receivable [Domain] Receivable [Domain] Other property and investments adjustment Total Other Property And Investments, Net Other Property And Investments, Net Deferred purchased gas costs Deferred purchased gas costs Increase in deferred purchased gas costs Increase (Decrease) in Deferred Gas Cost Regulated operations revenues Total Regulated operations revenues Regulated Operating Revenue, Gas MountainWest Acquisition Loan MountainWest Acquisition Loan [Member] MountainWest Acquisition Loan Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Regulated operations plant: Public Utilities, Property, Plant and Equipment, Net [Abstract] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Debt, basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Number of contracts with original duration more than one year Revenue Recognition, Number Of Contracts With Original Duration More Than One Year Revenue Recognition, Number Of Contracts With Original Duration More Than One Year Other Payments for (Proceeds from) Other Investing Activities Industrial/other Industrial/other [Member] Industrial/other. Short-term Debt, Type [Axis] Short-Term Debt, Type [Axis] Debt instrument interest rate Debt Instrument, Interest Rate, Stated Percentage Additional paid-in capital Additional Paid in Capital, Common Stock Utility infrastructure services revenues Regulated Operating Revenue, Utility Infrastructure Services Regulated Operating Revenue, Utility Infrastructure Services Net periodic benefit cost Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Restricted stock units (in shares) Incremental Common Shares Attributable to Dilutive Effect of Nonvested Shares with Forfeitable Dividends Schedule of Significant Items Included in Other Income (Deductions) Schedule of Other Nonoperating Income, by Component [Table Text Block] Repayments of debt Repayments of Debt Segment net income (loss) Segment net income (loss) Net Income (Loss) Attributable to Parent Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive securities (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Change in credit facility and commercial paper Proceeds From Repayments Of Lines Of Credit And Commercial Paper The net cash inflow or cash outflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with either short term or long term maturity that is collateralized (backed by pledge, mortgage or other lien in the entity's assets) and issuing (borrowing) and repaying commercial paper Accrued general taxes Accrual for Taxes Other than Income Taxes, Current Subsequent Event Type [Axis] Subsequent Event Type [Axis] Amortization of prior service costs Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Equity Component [Domain] Equity Component [Domain] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Secured Debt Secured Debt [Member] Ownership [Axis] Ownership [Axis] Changes in customer advances Changes In Customer Advances, Investing Activities Changes In Customer Advances, Investing Activities Equity AFUDC Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity Line of credit designated for working capital purposes Line Of Credit Facility Working Capital Purposes Line Of Credit Facility, Working Capital Purposes Plan Name [Axis] Plan Name [Axis] Contracts receivable, net Contracts receivable, net Contract with Customer, Asset, after Allowance for Credit Loss Effect of dilutive securities: Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Regulatory adjustment Accumulated Defined Benefit Plans Adjustment, Regulartory Adjustment, Attributable to Parent [Member] Accumulated Defined Benefit Plans Adjustment, Regulartory Adjustment, Attributable to Parent [Member] Non-regulated property, equipment, and intangibles Property Plant Equipment And Intangible Assets Gross Property plant equipment and intangible assets gross. Capital expenditures incurred but not yet paid, increase (decrease) Capital Expenditures Incurred But Not Yet Paid, Increase (Decrease) Capital Expenditures Incurred But Not Yet Paid, Increase (Decrease) SUPPLEMENTAL INFORMATION: Supplemental Cash Flow Information [Abstract] Term Loan Facility Due December 30, 2022 Term Loan Facility Due December 30, 2022 [Member] Term Loan Facility Due December 30, 2022 Transportation Transportation [Member] Transportation. Drum Drum [Member] Drum $400 Million Credit Facility $400 Million Credit Facility [Member] $400 Million Credit Facility [Member] Plan Name [Domain] Plan Name [Domain] Deferred purchased gas costs recovered or refunded period Deferred Purchased Gas Costs Recovered Or Refunded Period Deferred Purchased Gas Costs Recovered Or Refunded Period Goodwill [Line Items] Goodwill [Line Items] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Borrowings outstanding under facility Long-Term Line of Credit Entity Address, State or Province Entity Address, State or Province Prior service cost Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax 2008 Series A, due 2038 Variable Rate Bonds Two Thousand And Eight Series A- Due Two Thousand And Thirty Eight [Member] Variable Rate Bonds Two Thousand and Eight Series A Due Two Thousand and Thirty Eight [Member] Qualified Retirement Plan Other Pension Plan [Member] Net cash provided by (used in) operating activities Net Cash Provided by (Used in) Operating Activities Contract with Customer, Basis of Pricing [Axis] Contract with Customer, Basis of Pricing [Axis] Proceeds from the sale of business, net of cash sold Proceeds from Divestiture of Businesses Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Operating expenses: Costs and Expenses [Abstract] SERP Supplemental Employee Retirement Plan [Member] Legal Entity [Axis] Legal Entity [Axis] Long-term debt, less current maturities Long-term debt, less current maturities Long-Term Debt, Excluding Current Maturities Revenue Recognition and Deferred Revenue [Abstract] CASH FLOW FROM INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities [Abstract] Centuri secured term loan facility Centuri Secured Term Loan Facility [Member] Centuri Secured Term Loan Facility Common stock issuances Common stock issued, amount Stock Issued During Period, Value, New Issues Gas infrastructure services Gas Infrastructure Services [Member] Gas Infrastructure Services Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Accounts Receivable, net of allowances Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block] Accrued utility revenue Accrued Utility Revenue Accrued utility revenue. Document Type Document Type Disposition consideration adjustment Disposal Group, Not Discontinued Operation, Consideration Adjustment Disposal Group, Not Discontinued Operation, Consideration Adjustment Schedule of Related Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss) Schedule Of Related Tax Effects Allocated To Components Of Other Comprehensive Income (Loss) [Table Text Block] Related tax effects of defined benefit pension plans and designated hedging activities reclassifications and amounts arising during the period included in other comprehensive income (loss). Accrued purchased gas cost Accrued Purchased Gas Costs Accrued Purchased Gas Costs Summary of Information about Receivables, Revenue Earned on Contracts in Progress in Excess of Billings, Which are Included Within Accounts Receivable, Net of Allowances, and Amounts Billed in Excess of Revenue Earned on Contracts Schedule Of Information About Receivables Revenue Earned On Contracts In Progress In Excess Of Billings And Amounts Billed In Excess Of Revenue Earned On Contracts [Table Text Block] Schedule Of Information About Receivables Revenue Earned On Contracts In Progress In Excess Of Billings And Amounts Billed In Excess Of Revenue Earned On Contracts Revenue earned on contracts in progress in excess of billings Revenue Earned On Contracts In Progress In Excess Of Billings Revenue Earned On Contracts In Progress In Excess Of Billings Segments [Axis] Segments [Axis] Debt Debt Disclosure [Text Block] Components of Net Periodic Benefit Cost Compensation and Employee Benefit Plans [Text Block] Product and Service [Domain] Product and Service [Domain] Entity Shell Company Entity Shell Company Notes, 2.2%, due 2030 Debentures Notes Two Point Two Percentage, Due Two Thousand And Thirty [Member] Debentures Notes Two Point Two Percentage, Due Two Thousand And Thirty Gross proceeds Proceeds From Issuance Of Common Stock, Gross Proceeds From Issuance Of Common Stock, Gross Subsequent Event Subsequent Event [Member] Consolidation Items [Domain] Consolidation Items [Domain] Schedule of Utility Infrastructure Services Contracts Receivable Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Document Period End Date Document Period End Date Residential Residential [Member] Residential. Interest income Interest Income, Other Schedule of Rollforward of Accumulated Other Comprehensive Income Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Total assets Assets Debt Disclosure [Abstract] Debt Disclosure [Abstract] Earnings (loss) per share: Earnings Per Share [Abstract] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Current maturities of long-term debt Less: current maturities Long-Term Debt, Current Maturities Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Gas pipe materials and operating supplies Materials, Supplies, and Other Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Other Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Other Line of Credit Line of Credit [Member] Percentage of redeemable noncontrolling interest redeemed Redeemable Noncontrolling Interest, Percentage Redeemed Redeemable Noncontrolling Interest, Percentage Redeemed Income (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Prepaid and other current assets Prepaid and other current assets Prepaid Expense and Other Assets, Current Segments [Domain] Segments [Domain] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Customer [Axis] Customer [Axis] Foreign Currency Items Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member] Interest cost Defined Benefit Plan, Interest Cost Redemption of equity interest from noncontrolling party Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Gas plant Public Utilities, Property, Plant and Equipment, Gas Plant Public Utilities, Property, Plant and Equipment, Gas Plant Movement In Redeemable Noncontrolling Interest [Roll Forward] Movement In Redeemable Noncontrolling Interest [Roll Forward] Movement In Redeemable Noncontrolling Interest [Roll Forward] Income taxes receivable, net Income Taxes Receivable, Current Other comprehensive income (loss) before reclassifications, net of tax Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Foreign currency exchange translation adjustment Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Parent Entity Registrant Name Entity Registrant Name Common stock issuances (in shares) Number of shares sold (in shares) Stock Issued During Period, Shares, New Issues Goodwill Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block] Foreign currency translation adjustment Goodwill, Foreign Currency Translation Gain (Loss) Foreign currency items Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Notes, 5.45%, due 2028 Debentures Notes 5.450% Due 2028 [Member] Debentures Notes 5.450% Due 2028 Entity Address, City or Town Entity Address, City or Town Beginning balance, attributable to parent, before tax Ending balance, attributable to parent, before tax Stockholders' Equity Attributable To Parent, Before Tax Stockholders' Equity Attributable To Parent, Before Tax Other current assets and liabilities Other current assets and liabilities Increase (Decrease) in Other Current Assets and Liabilities, Net Condensed Income Statements, Captions [Line Items] Condensed Income Statements, Captions [Line Items] Beginning balance Ending balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Revolving credit facility and commercial paper Revolving Credit Facility And Commercial Paper [Member] Revolving Credit Facility And Commercial Paper [Member] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Entity Emerging Growth Company Entity Emerging Growth Company Common stock, par (in USD per share) Common Stock, Par or Stated Value Per Share Contract with Customer, Basis of Pricing [Domain] Contract with Customer, Basis of Pricing [Domain] Statutory income tax rate Statutory Income Tax Rate, Percent Statutory Income Tax Rate, Percent Other comprehensive income (loss) before reclassifications, tax Other Comprehensive Income (Loss) before Reclassifications, Tax Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Trading Symbol Trading Symbol Entity File Number Entity File Number Reclassification from AOCI, tax Reclassification from AOCI, Current Period, Tax Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Accrued interest Interest Payable, Current $250 Million Term Loan $250 Million Term Loan [Member] $250 Million Term Loan Comprehensive income attributable to noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Beginning balance, attributable to parent, tax Ending balance, attributable to parent, tax Stockholders' Equity Attributable To Parent, Tax Stockholders' Equity Attributable To Parent, Tax Disposal Group Classification [Axis] Disposal Group Classification [Axis] Cash and cash equivalents included in current assets held for sale at beginning of period Cash And Cash Equivalents Included In Current Assets Held For Sale Cash And Cash Equivalents Included In Current Assets Held For Sale Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Entity Information [Line Items] Entity Information [Line Items] Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Notes, 3.18%, due 2051 Debentures Notes Three Point Eighteen Percentage, Due Two Thousand And Fifty One [Member] Debentures Notes Three Point Eighteen Percentage, Due Two Thousand And Fifty One Receivable from parent Centuri accounts receivable for services provided to Southwest Due from Related Parties, Current Total operating revenues Regulated and Unregulated Operating Revenue Other income (deductions) Other Nonoperating Income (Expense) [Abstract] Money market fund investments Cash and Cash Equivalents, Fair Value Disclosure Revision of Prior Period, Error Correction, Adjustment Revision of Prior Period, Error Correction, Adjustment [Member] Accounts payable Increase (Decrease) in Accounts Payable Background, Organization, and Summary of Significant Accounting Policies Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] Revenues Revenues Net forward-starting interest rate swaps Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Change in COLI policies Life Insurance, Corporate or Bank Owned, Change in Value Beginning balance, before tax Ending balance, before tax Stockholders' Equity, Including Portion Attributable To Noncontrolling Interest, Before Tax Stockholders' Equity, Including Portion Attributable To Noncontrolling Interest, Before Tax Other comprehensive income (loss), net of tax Other comprehensive income, net of tax Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract] Restricted Stock/Unit Plan, and Management Incentive Plan Restricted Stock/Unit Plan, And Management Incentive Plan [Member] Restricted Stock/Unit Plan, And Management Incentive Plan [Member] Credit Facility [Domain] Credit Facility [Domain] Schedule of Goodwill Schedule of Goodwill [Table Text Block] Interest paid, net of amounts capitalized Interest paid, net of amounts capitalized Interest Paid, Excluding Capitalized Interest, Operating Activities Basic (in USD per share) Earnings Per Share, Basic Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Reclassification from AOCI, before Tax Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Regulated gas transportation and storage revenues Regulated Gas Transportation And Storage Revenues [Member] Regulated Gas Transportation And Storage Revenues Pension plans other comprehensive income (loss) Defined Benefit Plans Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Corporate and administrative Corporate, Non-Segment [Member] Loss contingency, damages sought value (up to) Loss Contingency, Damages Sought, Value Total equity Beginning balance, attributable to parent Ending balance, attributable to parent Stockholders' Equity Attributable to Parent Payable to parent Due to Affiliate, Current Dividends declared Dividends declared to Southwest Gas Holdings, Inc. Dividends, Common Stock Condensed Income Statement [Table] Condensed Income Statement [Table] Ownership [Domain] Ownership [Domain] NGL revenues NGL Revenues [Member] NGL Revenues Other Current Liabilities Other Current Liabilities Policy [Policy Text Block] Other Current Liabilities Policy Entity Interactive Data Current Entity Interactive Data Current Sale of stock, number of shares Sale of Stock, Number of Shares Issued in Transaction Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Changes in current assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Notes, 4.15%, due 2049 Debentures Notes Four Point Fifteen Percentage, Due Two Thousand And Forty Nine [Member] Debentures Notes Four Point Fifteen Percentage, Due Two Thousand And Forty Nine Money Market Funds Money Market Funds [Member] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Retained earnings Retained Earnings [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] 8% Series, due 2026 Debentures Eight Percentage Series Due Two Thousand And Twenty Six [Member] Debentures Eight Percentage Series Due Two Thousand And Twenty Six [Member] Common stock shares Common Stock [Member] Receivable Type [Axis] Receivable Type [Axis] Share-based compensation Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Number of reportable segments Number of Reportable Segments Transition services agreement, period Disposal Group, Transition Services Agreement, Period Disposal Group, Transition Services Agreement, Period Statement [Table] Statement [Table] Document Quarterly Report Document Quarterly Report Discontinued Operations and Disposal Groups [Abstract] Current assets: Assets, Current [Abstract] Change in short-term debt Change In Short-Term Debt Change In Short-Term Debt Disposal Group, Held-for-sale, Not Discontinued Operations Disposal Group, Held-for-sale, Not Discontinued Operations [Member] Schedule of Other Property and Investments Investment [Table Text Block] Nature of Operations Nature Of Operations [Policy Text Block] Nature Of Operations [Policy Text Block] Other comprehensive income (loss), before tax Other Comprehensive Income (Loss), before Tax Loss contingency, damages sought period Loss Contingency, Damages Sought, Period Loss Contingency, Damages Sought, Period Sale of stock, amount of common stock available for sale Sale Of Stock, Amount Of Common Stock Available For Sale Sale Of Stock, Amount Of Common Stock Available For Sale Retained earnings Retained Earnings (Accumulated Deficit) Disposal Group Name [Axis] Disposal Group Name [Axis] AOCI Including Portion Attributable to Noncontrolling Interest AOCI Including Portion Attributable to Noncontrolling Interest [Member] Accounts receivable, net of allowance Accounts Receivable, after Allowance for Credit Loss, Current Ownership percentage disposed Disposal Group, Including Discontinued Operation, Ownership Percentage in Disposed Asset Disposal Group, Including Discontinued Operation, Ownership Percentage in Disposed Asset Equity Components [Axis] Equity Components [Axis] Net cost of gas sold Decrease of net cost of gas sold Utilities Operating Expense, Gas and Petroleum Purchased Dividend Reinvestment and Stock Purchase Plan Dividend Reinvestment And Stock Purchase Plan [Member] Dividend Reinvestment And Stock Purchase Plan [Member] Revision of Prior Period [Domain] Revision of Prior Period [Domain] Document Fiscal Year Focus Document Fiscal Year Focus CASH FLOW FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Statement [Line Items] Statement [Line Items] Discontinued operation, consideration Disposal Group, Including Discontinued Operation, Consideration Master services agreement Master Services Agreement [Member] Master Services Agreement [Member] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Total other income and (expenses) Nonoperating Income (Expense) Variable Rate [Domain] Variable Rate [Domain] Accumulated other comprehensive loss AOCI Attributable to Parent AOCI Attributable to Parent [Member] Other Comprehensive Income and Accumulated Other Comprehensive Income Comprehensive Income (Loss) Note [Text Block] Document Transition Report Document Transition Report Local Phone Number Local Phone Number Operating income Operating Income (Loss) Total capitalization Capitalization, Long-Term Debt and Equity Accrual for repurchase of redeemable noncontrolling interest Accrual For Repurchase Of Redeemable Noncontrolling Interest Accrual For Repurchase Of Redeemable Noncontrolling Interest Linetec Linetec Services, LLC [Member] Linetec Services, LLC [Member] Recent Accounting Standards Updates New Accounting Pronouncements, Policy [Policy Text Block] Discontinued Operations, Disposed of by Sale Discontinued Operations, Disposed of by Sale [Member] Weighted average shares: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Common stock, outstanding (in shares) Beginning balance (in shares) Ending balance (in shares) Common Stock, Shares, Outstanding Equity AFUDC Increase (Decrease) in Allowance for Equity Funds Used During Construction Goodwill Goodwill Goodwill, beginning balance Goodwill, ending balance Goodwill Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities: Adjustments to reconcile net income to net cash provided by (used in) operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Income tax expense Income Tax Expense (Benefit) Amortization of prior service cost Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] Sale of stock, amount of common stock offered for sale Sale Of Stock, Amount Of Common Stock Offered For Sale Sale Of Stock, Amount Of Common Stock Offered For Sale Amounts billed in excess of revenue earned on contracts Contract with Customer, Receivable, after Allowance for Credit Loss Issuance of short-term debt Proceeds from Short-Term Debt Income Statement [Abstract] Income Statement [Abstract] Additional paid-in capital Additional Paid-in Capital [Member] Document Fiscal Period Focus Document Fiscal Period Focus Medium-term notes, 6.76% series, due 2027 Debentures Medium Term Notes Six Point Seven Six Percentage Series Due Two Thousand And Twenty Seven [Member] Debentures Medium Term Notes Six Point Seven Six Percentage Series Due Two Thousand and Twenty Seven [Member] Previous Owner Of Linetec Previous Owner Of Linetec [Member] Previous Owner Of Linetec Utility infrastructure services expenses Cost of Goods and Services Sold Notes, 4.875%, due 2043 Debentures Notes Four Point Eight Seven Five Percentage Due Two Thousand And Forty Three [Member] Debentures Notes Four Point Eight Seven Five Percentage Due Two Thousand And Forty Three [Member] Diluted (in shares) Weighted average diluted shares (in shares) Weighted Average Number of Shares Outstanding, Diluted Non-regulated accumulated provision for depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Defined benefit pension plans: Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax [Abstract] Miscellaneous income and (expense) Miscellaneous Income Expense Miscellaneous income (expense). Alternative base rate Base Rate [Member] Other components of net periodic benefit cost Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit Total noncurrent assets Assets, Noncurrent, Other than Noncurrent Investments and Property, Plant and Equipment Common stock, $1 par (authorized - 120,000,000 shares; issued and outstanding - 71,330,991 and 67,119,143 shares) Common stock Common Stock, Value, Issued Carrying Amount Reported Value Measurement [Member] Capitalization: Capitalization, Long-Term Debt and Equity [Abstract] Term Loan Facility Due December 30, 2023 Term Loan Facility Due December 30, 2023 [Member] Term Loan Facility Due December 30, 2023 Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Centuri Centuri Centuri Group, Inc. [Member] Centuri Group, Inc. [Member] Other receivables Other Receivables [Member] Other Receivables Revenues from external customers Operating Segments [Member] Other property and investments, net Other Property And Investments Aggregate carrying amount, as of the balance sheet date, of other property and investments not separately presented elsewhere in the balance sheet. Centuri distribution to redeemable noncontrolling interest Distribution To Redeemable Noncontrolling Interest Distribution To Redeemable Noncontrolling Interest Other costs Other Nonoperating Expense Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Loans Payable Loans Payable [Member] Net income attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Current liabilities: Liabilities, Current [Abstract] Issuance of long-term debt, net Proceeds from Issuance of Long-Term Debt Common stock, issued (in shares) Common Stock, Shares, Issued Current liabilities held for sale Disposal Group, Including Discontinued Operation, Liabilities, Current Customer deposits Contract with Customer, Liability, Current Utility Infrastructure Services Utility Infrastructure Services Segment [Member] Utility Infrastructure Services Segment [Member] Southwest Gas Holdings, Inc. Parent [Member] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Deferred Purchased Gas Costs Deferred Purchased Costs [Policy Text Block] Deferred Purchased Costs Amendment Flag Amendment Flag Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Debt instrument face amount Debt Instrument, Face Amount Common Stock Common Stock Disclosure [Text Block] Common Stock Disclosure [Text Block] Total other comprehensive income, net of tax Other Comprehensive Income (Loss), Net of Tax Comprehensive income (loss) attributable to Southwest Gas Holdings, Inc. Comprehensive Income (Loss), Net of Tax, Attributable to Parent Schedule of Segment Reporting Information Schedule of Segment Reporting Information, by Segment [Table Text Block] Impairment of asset held for sale adjustment Impairment of Long-Lived Assets to be Disposed of Entity Current Reporting Status Entity Current Reporting Status Schedule of Amount Recognized Before Income Tax in Accumulated Other Comprehensive Income Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] Other current liabilities Other current liabilities Other Liabilities, Current Accrued taxes Increase (Decrease) in Accrued Taxes Payable Deferred charges and other assets Deferred charges and other assets Other Assets, Noncurrent Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Tax-exempt Series A, due 2028 Variable Rate Bonds Tax Exempt Series A- Due Two Thousand And Twenty Eight [Member] Variable Rate Bonds Tax Exempt Series Due Two Thousand and Twenty Eight [Member] Large commercial Large Commercial [Member] Large commercial. Centuri, MountainWest, and Southwest Gas Holdings, Inc. Centuri, MountainWest, And Southwest Gas Holdings, Inc. [Member] Centuri, MountainWest, And Southwest Gas Holdings, Inc. Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Unamortized discount and debt issuance costs Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Less: amount recognized in regulatory assets Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Amount Recognized Regulatory Assets, Before Tax Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Amount Recognized Regulatory Assets, Before Tax Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Net actuarial gain (loss) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Effects of currency translation on cash and cash equivalents Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations Entities [Table] Entities [Table] Sale of stock, underwriters' discount Sale of Stock, Underwriters' Discount Sale of Stock, Underwriters' Discount Retirement of long-term debt Retirement of long-term debt Repayments of Long-Term Debt Net defined benefit pension plans Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Net regulated operations plant Public Utilities, Property, Plant and Equipment, Net Other property and investments Property, Plant and Equipment, Other, Net Secured Overnight Financing Rate (SOFR) Secured Overnight Financing Rate (SOFR) [Member] Secured Overnight Financing Rate (SOFR) Loss on disposal adjustment Loss on disposal adjustment Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Fixed price contracts Fixed-Price Contract [Member] Long-term debt Long-term debt outstanding Long-Term Debt Other income (deductions) Total other income (deductions) Other Nonoperating Income (Expense) Sale of stock, price per share (in USD per share) Sale of Stock, Price Per Share Common stock, authorized (in shares) Common Stock, Shares Authorized Weighted average price per share (in USD per share) Common Stock Weighted Average Issue Price Per Share Common stock weighted average issue price per share. Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Noncurrent assets: Noncurrent assets: Assets, Noncurrent [Abstract] Significant Accounting Policies [Table] Significant Accounting Policies [Table] Significant Accounting Policies [Table] Accumulated other comprehensive loss, net Accumulated Other Comprehensive Income (Loss), Net of Tax Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Total current assets Assets, Current Income taxes paid, net Income taxes paid (received), net Income Taxes Paid, Net Small commercial Small Commercial [Member] Small commercial. Entity Small Business Entity Small Business FSIRS AOCI, Derivative Qualifying as Hedge, Excluded Component, Parent [Member] Measurement Basis [Axis] Measurement Basis [Axis] Common stock issued (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period Schedule of Net Periodic Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Dividends declared per common share (in USD per share) Common Stock, Dividends, Per Share, Declared Operating revenues: Revenues [Abstract] Transaction price allocated to unsatisfied performance obligations of contracts, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Foreign transaction gain (loss) Foreign Currency Transaction Gain (Loss), Realized Amortization of prior service cost Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax Debentures Notes Five Point Eight Percentage, Due Two Thousand And Twenty Seven Debentures Notes Five Point Eight Percentage, Due Two Thousand And Twenty Seven [Member] Debentures Notes Five Point Eight Percentage, Due Two Thousand And Twenty Seven Accounts receivable, net of allowances Accounts receivable, net of allowance Increase (Decrease) in Accounts Receivable Short-term debt Short-term debt Short-Term Debt Title of 12(b) Security Title of 12(b) Security Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Ownership percentage by noncontrolling owners Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners $550 Million Term Loan Credit Agreement Due October 2024 $550 Million Term Loan Credit Agreement Due October 2024 [Member] $550 Million Term Loan Credit Agreement Due October 2024 Centuri secured revolving credit facility Centuri Secured Revolving Credit Facility [Member] Centuri secured revolving credit facility. Total operating expenses Costs and Expenses Southwest Gas Corporation Southwest Gas Corporation [Member] Southwest gas corporation. Debt Instrument [Line Items] Debt Instrument [Line Items] Class of Stock [Line Items] Class of Stock [Line Items] Segment Information Segment Reporting Disclosure [Text Block] Centuri secured term loan facility Centuri Term Loan Facility [Member] Centuri term loan facility. CAPITALIZATION AND LIABILITIES Liabilities and Equity [Abstract] Fair Value Estimate of Fair Value Measurement [Member] Other revenues Other Revenues [Member] Other Revenues Net proceeds from sale of stock Sale of Stock, Consideration Received on Transaction Accounts payable Accounts Payable, Current Less: accumulated depreciation Less: accumulated depreciation Public Utilities, Property, Plant and Equipment, Accumulated Depreciation Changes in deferred charges and other assets Changes in deferred charges and other assets Increase (Decrease) in Other Operating Assets Accumulated removal costs Other Accrued Liabilities, Noncurrent Debt issuance costs written off Write off of Deferred Debt Issuance Cost Alternative revenue program revenues (deferrals) Alternative Revenue Program Revenues (Deferrals) Alternative revenue program revenues (deferrals). Contributions from parent Proceeds from Contributions from Parent Entity Filer Category Entity Filer Category Summary of Redeemable Noncontrolling Interest Redeemable Noncontrolling Interest [Table Text Block] Issuance of common stock, net Net proceeds Proceeds from Issuance of Common Stock Basic (in shares) Weighted average basic shares (in shares) Weighted Average Number of Shares Outstanding, Basic Debt secured by assets Debt Instrument, Collateral Amount Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] $450 Million Term Loan $450 Million Term Loan [Member] $450 Million Term Loan Variable Rate Debt Agreements With Reference To LIBOR Variable Rate Debt Agreements With Reference To LIBOR [Member] Variable Rate Debt Agreements With Reference To LIBOR Other Other Infrastructure Services [Member] Other Infrastructure Services Security Exchange Name Security Exchange Name Medium-term notes, 7.92% series, due 2027 Debentures Medium Term Notes Seven Point Nine Two Percentage Series Due Two Thousand And Twenty Seven [Member] Debentures Medium Term Notes Seven Point Nine Two Percentage Series Due Two Thousand and Twenty Seven [Member] Amounts reclassified into net income FSIRS amounts reclassified to net income, net of tax Amounts reclassified into net income (loss) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Redeemable noncontrolling interests Redeemable noncontrolling interest, beginning balance Redeemable noncontrolling interest, ending balance Redeemable Noncontrolling Interest, Equity, Carrying Amount Current assets held for sale Current assets held for sale adjustment Disposal Group, Including Discontinued Operation, Assets, Current Construction work in progress Public Utilities, Property, Plant and Equipment, Construction Work in Progress Intersegment revenues Segment Reconciling Items [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Certain Members Of Riggs Distler Management Certain Members Of Riggs Distler Management [Member] Certain Members Of Riggs Distler Management Short-term Debt, Type [Domain] Short-Term Debt, Type [Domain] Revenue from contracts with customers Revenue from contracts with customers Revenue from Contract with Customer, Excluding Assessed Tax $300 Million Credit Facility $300 Million Credit Facility [Member] $300 Million Credit Facility Service cost Defined Benefit Plan, Service Cost Forward-starting interest rate swaps (“FSIRS”): Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract] Cover [Abstract] Cover [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Goodwill impairment loss Goodwill, Impairment Loss Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Allowance for doubtful accounts Contract with Customer, Asset, Allowance for Credit Loss Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Amortization of net actuarial (gain)/loss Amortization of net actuarial loss Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] Deferred income taxes Deferred income taxes Increase (Decrease) in Deferred Income Taxes Revenue Revenue from Contract with Customer [Text Block] MountainWest MountainWest [Member] MountainWest Segment Reporting [Abstract] Segment Reporting [Abstract] Accrued utility revenue Accrued utility revenue Increase (Decrease) in Contract with Customer, Asset Natural Gas Distribution Natural Gas Distribution Segment [Member] Natural Gas Distribution Segment Regulatory adjustment Regulatory adjustment Other Comprehensive Income Defined Benefit Plans Regulatory Adjustment Net of Tax The portion of the pension, PBOP, and SERP liability that is recoverable in rates net-of-tax. Amortization of net actuarial loss Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax Notes, 3.7%, due 2028 Debentures Notes Three Point Seven Percentage Due Two Thousand And Twenty Eight [Member] Debentures notes three point seven percentage due two thousand and twenty eight. Amortization of net actuarial loss Defined Benefit Plan, Amortization of Gain (Loss) Withholding remittance - share-based compensation Withholding remittance - share-based compensation Payment, Tax Withholding, Share-Based Payment Arrangement Total capitalization and liabilities Liabilities and Equity Debt instrument, term Debt Instrument, Term Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Goodwill [Roll Forward] Goodwill [Roll Forward] Net income attributable to redeemable noncontrolling interests Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Bid contract Bid Contract [Member] Bid contract. Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Disposal Group Name [Domain] Disposal Group Name [Domain] AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Acquisition of businesses, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Deferred purchased gas costs Deferred Gas Cost Equity Shelf Program Equity Shelf Program [Member] Equity Shelf Program [Member] Current Fiscal Year End Date Current Fiscal Year End Date Diluted (in USD per share) Earnings Per Share, Diluted Sale of Stock [Domain] Sale of Stock [Domain] Notes, 4.05%, due 2032 Debentures Notes Four Point Zero Five Percentage Due Two Thousand And Thirty Two [Member] Debentures Notes Four Point Zero Five Percentage Due Two Thousand And Thirty Two Less: agent commissions Payments of Stock Issuance Costs Gains on sale of property and equipment Gain on sale of property Gain (Loss) on Disposition of Property Plant Equipment Ownership percentage by Parent Noncontrolling Interest, Ownership Percentage by Parent Consolidation Items [Axis] Consolidation Items [Axis] Total current liabilities Liabilities, Current Net income Net income Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest Notes, 6.1%, due 2041 Debentures Notes 6.1% Due 2041 [Member] Debentures Notes Six Point One Percentage Due Two Thousand And Forty One [Member] Dispositions Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Transaction price allocated to unsatisfied performance obligations of contracts Revenue, Remaining Performance Obligation, Amount Deferred income taxes and other credits: Other Liabilities, Noncurrent [Abstract] Accrued purchased gas cost Unrecovered Costs for Purchased Gas Amount Other income and (expenses): Nonoperating Income (Expense) [Abstract] Other comprehensive income (loss) before reclassifications, before tax Other Comprehensive Income (Loss), before Reclassifications, before Tax 2003 Series A, due 2038 Variable Rate Bonds Two Thousand And Three Series A- Due Two Thousand And Thirty Eight [Member] Variable Rate Bonds Two Thousand and Three Series A Due Two Thousand and Thirty Eight [Member] Beginning balance, tax Ending balance, tax Stockholders' Equity, Including Portion Attributable To Noncontrolling Interest, Tax Stockholders' Equity, Including Portion Attributable To Noncontrolling Interest, Tax Deferred income taxes and investment tax credits, net Deferred Income Taxes And Unamortized Investment Tax Credits Represents deferred tax liabilities, which result from applying the applicable tax rate to net taxable temporary differences pertaining to each jurisdiction to which the entity is obligated to pay income tax. Additionally, this element includes the future effects on income taxes attributable to investment tax credits. Entity Address, Address Line Two Entity Address, Address Line Two Entity Address, Address Line One Entity Address, Address Line One Other comprehensive income (loss), tax Other Comprehensive Income (Loss), Tax Contracts receivable, gross Contract with Customer, Asset, before Allowance for Credit Loss Other, including principal payments on finance leases Other Proceeds from (Payments for) Other Financing Activities Accrued post-closing payment Disposal Group, Not Discontinued Operation, Accrued Post-Closing Payment Disposal Group, Not Discontinued Operation, Accrued Post-Closing Payment Product and Service [Axis] Product and Service [Axis] Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Pipeline and Storage Pipeline And Storage Segment [Member] Pipeline And Storage Segment Number of performance share units granted (in shares) Number Of Performance Share Units Granted Number Of Performance Share Units Granted. Net interest deductions Net interest deductions Interest expense Interest Expense Credit Facility [Axis] Credit Facility [Axis] Time and materials contracts Time-and-Materials Contract [Member] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Electric power infrastructure services Electric Power Infrastructure Services [Member] Electric Power Infrastructure Services Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Schedule of Carrying Amounts and Estimated Fair Values of Long-Term Debt Schedule of Long-Term Debt Instruments [Table Text Block] Equity [Abstract] Equity [Abstract] Entity Tax Identification Number Entity Tax Identification Number Centuri Secured Term Loan Facility And Revolving Credit Facility Centuri Secured Term Loan Facility And Revolving Credit Facility [Member] Centuri Secured Term Loan Facility And Revolving Credit Facility Line of credit designated as long term debt Line Of Credit Facility Amount Classified As Long Term Debt Line Of Credit Facility, Amount Classified As Long-Term Debt Summary of Revenue Disaggregated by Service Type and Contract Type Disaggregation of Revenue [Table Text Block] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Debentures Debentures [Member] Debentures [Member] Dividends declared but not yet paid Dividends Payable, Current Net actuarial loss Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax Change in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Entity Central Index Key Entity Central Index Key Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Operations and maintenance Utilities Operating Expense, Maintenance and Operations Industrial development revenue bonds Industrial Development Revenue Bonds [Member] Industrial Development Revenue Bonds [Member] Notes, 3.8%, due 2046 Debentures Notes Three Point Eight Percentage Due Two Thousand And Forty Six [Member] Debentures notes three point eight percentage due two thousand and forty six. Entity [Domain] Entity [Domain] 2009 Series A, due 2039 Variable Rate Bonds Two Thousand And Nine Series A- Due Two Thousand And Thirty Nine [Member] Variable Rate Bonds Two Thousand and Nine Series A Due Two Thousand and Thirty Nine [Member] City Area Code City Area Code ASSETS Assets [Abstract] Recognized in AOCI Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax Certain Funds Affiliated With Carl C. Icahn Certain Funds Affiliated With Carl C. Icahn [Member] Certain Funds Affiliated With Carl C. Icahn Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Revision of Prior Period, Adjustment Revision of Prior Period, Adjustment [Member] Retirement Benefits [Abstract] Retirement Benefits [Abstract] Other debt obligations Other Debt Obligations [Member] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Sale of Stock [Axis] Sale of Stock [Axis] Other revenues Other Revenue Other Revenue Goodwill impairment and loss on sale Goodwill Impairment And Loss On Sale Goodwill Impairment And Loss On Sale Prepaid and other current assets Prepaid And Other Current Assets Policy [Policy Text Block] Prepaid And Other Current Assets Policy CASH FLOW FROM FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Earnings Per Share Earnings Per Share, Policy [Policy Text Block] Changes in undistributed stock compensation Share-Based Payment Arrangement, Noncash Expense Variable Rate [Axis] Variable Rate [Axis] Net cash surrender value of COLI policies Cash Surrender Value of Life Insurance Income taxes payable, net Income Taxes Payable, Net Income Taxes Payable, Net Schedule Of Accounts Receivable Not Eliminated During Consolidation Schedule Of Accounts Receivable Not Eliminated During Consolidation [Table Text Block] Schedule Of Accounts Receivable Not Eliminated During Consolidation Total deferred income taxes and other credits Other Liabilities, Noncurrent Equity in earnings of unconsolidated investments Income (Loss) from Equity Method Investments Disposal Group Classification [Domain] Disposal Group Classification [Domain] Changes in other liabilities and deferred credits Increase (Decrease) in Other Operating Liabilities Construction expenditures and property additions Construction expenditures and property additions Payments to Acquire Property, Plant, and Equipment Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Customer [Domain] Customer [Domain] PBOP Other Postretirement Benefits Plan [Member] Taxes other than income taxes Taxes, Miscellaneous