Supplemental cash flow information: Supplemental Cash Flow Information [Abstract] Customer [Domain] Customer [Domain] Actuarial (gain) loss Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Letter of Credit Letter of Credit [Member] State Current State and Local Tax Expense (Benefit) Shares Vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Consolidated Entities [Axis] Consolidated Entities [Axis] Preferred Stock, Shares Outstanding Preferred Stock, Shares Outstanding Receivable Type [Axis] Receivable Type [Axis] Industrial Development Revenue Bonds Due 2027 Industrial Development Revenue Bonds Due 2027 [Member] Industrial Development Revenue Bonds Due 2027 [Member] Derivative, Liabilities, Fair Value Disclosure Derivative Liability Dividends on common stock Dividends, Common Stock, Cash Security Exchange Name Security Exchange Name Forfeited (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Regulatory Agency [Domain] Regulatory Agency [Domain] Commitments, Contingencies and Guarantees Commitments Contingencies and Guarantees [Text Block] Current liabilities Liability, Defined Benefit Plan, Current Senior Unsecured Notes Due 2021 Senior Unsecured Notes Due 2021 [Member] Senior Unsecured Notes Due 2021 Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Derivatives and Hedging Activities Derivatives, Policy [Policy Text Block] Shares available for grant Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Public Utilities, Term Extension of System Safety and Integrity Rider Public Utilities, Term Extension of System Safety and Integrity Rider Public Utilities, Term Extension of System Safety and Integrity Rider Black Hills Corporation’s common stock volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate 2023 Long-Term Debt, Maturity, Year Two Transmission/Other Transmission/Other [Member] Transmission/Other [Member] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Tax Credit Carryforward [Line Items] Tax Credit Carryforward [Line Items] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Intangible assets, amortization expense Amortization of Intangible Assets Investment Tax Credit Carryforward Investment Tax Credit Carryforward [Member] Additions for prior year tax positions Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Outstanding securities not included in the computation of diluted earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Materials, Supplies and Fuel Schedule of Inventory, Current [Table Text Block] Sale of Stock [Axis] Sale of Stock [Axis] Subsequent Events [Abstract] Reconciliation of Assets from Segment to Consolidated [Table] Reconciliation of Assets from Segment to Consolidated [Table] (Tax) benefit on net unrealized gains (losses) on commodity derivatives Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), Adjustments, Tax Total deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Cash and Cash Equivalents and Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Variable interest rate (percent) Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate Cash Flow Hedging Cash Flow Hedging [Member] Subsidiary of Common Parent Subsidiary of Common Parent [Member] Distribution Public Utilities, Property, Plant and Equipment, Distribution Lessor, Lease, Description [Table] Lessor, Lease, Description [Table] Colorado Electric and Black Hills Colorado IPP Colorado Electric and Black Hills Colorado IPP [Member] Colorado Electric and Black Hills Colorado IPP Valuation Allowance, Operating Loss Carryforwards SEC Schedule, 12-09, Valuation Allowance, Operating Loss Carryforward [Member] Award Type [Domain] Award Type [Domain] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Term Loan - repayments Repayments of Other Short-term Debt Repayments of Other Short-term Debt Local Phone Number Local Phone Number Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Recognized net actuarial loss (gain) Defined Benefit Plan, Amortization of Gain (Loss) Long-term Debt, Term Long-term Debt, Term Southern Star Central Gas Pipeline Southern Star Central Gas Pipeline [Member] Southern Star Central Gas Pipeline Goodwill and Intangible Assets Goodwill and Intangible Assets, Policy [Policy Text Block] Public Utilities, Term Extension of System Saftey and Integrity Rider Public Utilities, Term Extension of System Saftey and Integrity Rider Public Utilities, Term Extension of System Saftey and Integrity Rider Distributions to non-controlling interest Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Share-based Liabilities Paid Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Share-based Liabilities Paid Retained Earnings Retained Earnings [Member] Potential economic impact of the COVID-19 pandemic Trade Accounts Receivable [Member] Black Hills Corporation Pension Plan Black Hills Retirement Plan [Member] Black Hills Retirement Plan [Member] Fair Value Measurements Derivatives and Fair Value [Text Block] Derivative Assets, Noncurrent Derivative Assets, Noncurrent [Member] Line item in the statement of financial position in a classified presentation in which the fair value amounts of the derivative instruments are included. Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Contributions to defined benefit pension plans Payment for Pension Benefits Payment for Pension Benefits Silver Sage Wind Power Purchase Agreement Silver Sage Wind Power Purchase Agreement [Member] Silver Sage Wind Power Purchase Agreement [Member] Cash surrender value of life insurance contracts Cash Surrender Value [Member] Real Estate Funds Real Estate Funds [Member] Accrued property, plant and equipment purchases at December 31 Capital Expenditures Incurred but Not yet Paid Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Cheyenne Prairie Cheyenne Prairie [Member] Cheyenne Prairie Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Debt, Weighted Average Interest Rate Debt, Weighted Average Interest Rate Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Employee benefit plans Pension and Other Postretirement Benefits Cost (Reversal of Cost) Share-Based Compensation Compensation Related Costs, Policy [Policy Text Block] Other Nonoperating Income (Expense) Other Nonoperating Income (Expense) [Member] Earnings per share, Basic (usd per share) Earnings Per Share, Basic Property, Plant and Equipment (AFUDC) Public Utilities General Disclosures [Table Text Block] Revenue Revenue from Contract with Customer [Text Block] Annual TCJA-Related Customer Billing Credits Annual TCJA-Related Customer Billing Credits Annual TCJA-Related Customer Billing Credits Restricted cash and equivalents Restricted Cash and Investments, Current Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Regulatory Agency [Axis] Regulatory Agency [Axis] Nebraska Public Service Commission (NPSC) Nebraska Public Service Commission (NPSC) [Member] Nebraska Public Service Commission (NPSC) [Member] Public Utilities, Requested Term Extension of System Safety and Integrity Rider Public Utilities, Requested Term Extension of System Safety and Integrity Rider Public Utilities, Requested Term Extension of System Safety and Integrity Rider Fair Value Measurement [Domain] Fair Value Measurement [Domain] Black Hills Energy - Arkansas Gas Black Hills Energy, Arkansas Gas [Member] Black Hills Energy, Arkansas Gas Cumulative Effect, Period of Adoption, Adjustment Cumulative Effect, Period of Adoption, Adjustment [Member] Weighted average common shares outstanding: Weighted Average Number of Shares Outstanding, Basic and Diluted [Abstract] Weighted average number of shares of common stock, basic and diluted[Abstract] Commercial Paper Commercial Paper [Member] Net deferred tax liability Deferred Tax Liabilities, Net Other adjustments, net Other Noncash Income (Expense) Derivative Asset, Fair Value, Gross Asset Derivative Asset, Fair Value, Gross Asset Prior service cost (gain) Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), after Tax Accelerated depreciation, amortization and other plant-related differences Deferred Tax Liabilities, Property, Plant and Equipment Future Future [Member] 2022 Unrecorded Unconditional Purchase Obligation, to be Paid, Year One Regulatory Liability [Axis] Regulatory Liability [Axis] Entity Voluntary Filers Entity Voluntary Filers Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] Plan Name [Axis] Plan Name [Axis] Fixed Income Fixed Income Funds [Member] Long-term Debt Long-term Debt Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset Total deferred credits and other liabilities Liabilities, Other than Long-term Debt, Noncurrent Fair Value, Inputs, Level 1 Fair Value, Inputs, Level 1 Fair Value, Inputs, Level 1 [Member] Investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Deferred taxes on flow through accounting Flow Through Accounting [Member] The income tax effects of certain tax items are reflected in cost of service for the customer in which the tax benefits are realized and result in lower utiity rates. The regulatory treatment under flow-through accounting was applied for this tax benefit generated by utility costs that were previously capitalized for tax purposes in a rate case settlement and resulted in a lower rate increase. A regulatory asset was established to reflect the future increase in taxes payable recovered from sutomers as the temporarty difference reverses.[Member] Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Entity Small Business Entity Small Business Cash Cash and Cash Equivalents [Member] Amount of Payroll Tax (Social Security Employment Tax) Deferral Under the Cares Act Disbursed in the current year Amount of Payroll Tax (Social Security Employment Tax) Deferral Under the Cares Act Disbursed in the current year Amount of Payroll Tax (Social Security Employment Tax) Deferral Under the Cares Act - Disbursed in the current year Base Rate Base Rate [Member] Additions for current year tax positions Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Asset Retirement Obligations Asset Retirement Obligation [Policy Text Block] Public Utilities, General Disclosures [Line Items] Public Utilities, General Disclosures [Line Items] Noncontrolling Interest Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block] Transaction Type [Axis] Transaction Type [Axis] Production, Gas Gas Gathering and Processing Equipment [Member] Amendments Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment Debt Issuance Cost, Gross, Noncurrent Debt Issuance Cost, Gross, Noncurrent Additional paid-in capital Additional Paid in Capital LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Unrecognized Tax Benefits that Would Impact Effective Tax Rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Hedging Relationship [Domain] Hedging Relationship [Domain] Interest rate swaps Interest Rate Swap Interest Rate Swap [Member] Lessor - lease term Lessor, Operating Lease, Term of Contract Derivative liabilities, current Derivative Liability, Current Entity Interactive Data Current Entity Interactive Data Current Thereafter Long-Term Debt, Maturity, after Year Five Deferred Tax Assets, State Tax Credits Deferred Tax Assets, State Taxes Future Amortization Expense, Year Four Finite-Lived Intangible Asset, Expected Amortization, Year Four Finite-Lived Intangible Assets [Roll Forward] Finite-lived Intangible Assets [Roll Forward] Black Hills Wyoming Black Hills Wyoming [Member] Black Hills Wyoming [Member] Income tax receivable, net Income Taxes Receivable, Current Segment information included in Consolidated Balance Sheets Reconciliation of Assets from Segment to Consolidated [Table Text Block] Retirement Plan Name [Axis] Retirement Plan Name [Axis] Liability for Uncertain Tax Positions, Noncurrent, Period Start Liability for Uncertain Tax Positions, Noncurrent, Period End Liability for Uncertainty in Income Taxes, Noncurrent Lessor, Operating Lease, Payment to be Received, Fiscal Year Maturity Lessor, Operating Lease, Payment to be Received, Fiscal Year Maturity [Table Text Block] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items] Settlement of plan to provide TCJA-related customer billing credits to its customers Settlement of plan to provide TCJA-related customer billing credits to its customers Settlement of plan to provide TCJA-related customer billing credits to its customers. The billing credits, which represent a disposition of excess deferred income tax benefits resulting from the TCJA, will be delivered to customers in the next fiscal year. Income Tax Authority [Domain] Income Tax Authority [Domain] Debt Instrument, Debt to Capitalization Ratio Requirement Debt Instrument, Debt to Capitalization Ratio Requirement Debt Instrument, Debt to Capitalization Ratio Requirement Summary of Operating Loss Carryforwards Summary of Operating Loss Carryforwards [Table Text Block] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Fall River Solar Fall River Solar [Member] Fall River Solar, LLC Black Hills Energy, Kansas Gas Black Hills Energy, Kansas Gas [Member] Black Hills Energy, Kansas Gas Derivative assets, current Derivative Asset, Current Entity Address, State or Province Entity Address, State or Province Utilities Group Utilities Group [Member] Utilities Group - consists of our Electric Utilities and our Gas Utilities segments Liabilities Incurred Asset Retirement Obligation, Liabilities Incurred 2021 Lessor, Operating Lease, Payment to be Received, Year One South Dakota Electric and Wyoming Electric South Dakota Electric and Wyoming Electric [Member] South Dakota Electric and Wyoming Electric [Member] Current liabilities: Liabilities, Current [Abstract] Macquarie Energy, LLC Supply Agreement Macquarie Energy, LLC Supply Agreement [Member] Macquarie Energy, LLC Supply Agreement [Member] Receivable [Domain] Receivable [Domain] Operating Loss Carryforwards Valuation Allowance Operating Loss Carryforwards, Valuation Allowance Black Hills Wyoming and Wyoming Electric Black Hills Wyoming and Wyoming Electric [Member] Black Hills Wyoming and Wyoming Electric [Member] Wyodak Plant Wyodak Plant [Member] Wyodak Plant - power generation plant owned 20% by Black Hills Power and 80% by Pacificorp[Member] Supplemental Employee Retirement Plan Supplemental Employee Retirement Plan [Member] Unrecognized Tax Benefits, Interest Accrued Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Investment in privately held oil and gas company Equity Securities [Member] 2025 Defined Benefit Plan, Expected Future Benefit Payment, Year Four Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Instrument [Axis] Federal Current Federal Tax Expense (Benefit) Document Transition Report Document Transition Report Storm Costs Storm Costs [Member] Common stock $1.00 par value; 100,000,000 shares authorized; issued: 64,793,095 and 62,827,179, respectively Common Stock, Value, Issued Weighted-average recognition period Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Colorado Electric Colorado Electric [Member] Colorado Electric [Member] Net change in cash, restricted cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Schedule of Unit Contingent Capacity Schedule of Unit Contingent Capacity [Table Text Block] [Table Text Block] for Schedule of Unit Contingent Capacity [Table] Fair Value, by Balance Sheet Grouping Fair Value, by Balance Sheet Grouping [Table Text Block] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Revisions to Prior Estimates Asset Retirement Obligation, Revision of Estimate ICFR Auditor Attestation Flag ICFR Auditor Attestation Flag Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Cushion gas - depreciable Cushion Gas - Depreciable [Member] Cushion Gas - Depreciable [Member] Other revenues Other [Member] Other [Member] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] State deferred tax liability (a) Deferred Tax Liability, State Amount of deferred tax liabilities attributable to taxable temporary differences from state taxes. Legal Entity [Axis] Legal Entity [Axis] Equity compensation (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Revenue Refunded To Customers As A Result Of The TCJA Tax Benefits Revenue Refunded To Customers As A Result Of The TCJA Tax Benefits Revenue Refunded To Customers As A Result Of The TCJA Tax Benefits Goodwill [Line Items] Goodwill [Line Items] Post-65 for next year - All Plans Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year Reclassification adjustment of benefit plan liability - prior service cost (net of tax of $27, $23 and $19, respectively) Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax Northwest Pipeline - Wyoming Northwest Wyoming Pool [Member] Northwest Wyoming Pool [Member] Interest expense incurred net of amounts capitalized (including amortization of debt issuance costs, premiums and discounts) Interest expense Interest Costs Incurred Summary of Income Tax Contingencies Summary of Income Tax Contingencies [Table Text Block] Wygen I Generating Facility Wygen I Generating Facility [Member] Jointly Owned Wygen I Generating Facility [Member] Income Tax Authority [Axis] Income Tax Authority [Axis] Sale of Stock, Consideration Received on Transaction Sale of Stock, Consideration Received on Transaction Derivative Liabilities, Current Derivative Liabilities, Current [Member] Line item in the statement of financial position in a classified presentation in which the fair value amounts of the derivative instruments are included. Northern Natural Gas - Demarc NNG-Demarc [Member] NNG-Demarc Entity [Domain] Entity [Domain] Accrued liabilities Total accrued liabilities Accrued Liabilities, Current Revenue from contracts with customers Revenue from Contract with Customer, Excluding Assessed Tax The percentage paid in cash for the accrued equity portion of the performance share plan upon change in control The percentage paid in cash for the accrued equity portion of the performance share plan upon change in control The percentage paid in cash for the accrued equity portion of the performance share plan upon change in control Term of Evergreen Contracts Unrecorded Unconditional Purchase Obligation, Term Electric transmission Electric Transmission [Member] Issuance costs Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs Reclassification adjustment of benefit plan liability - net loss (net of tax of $(665), $(958) and $434, respectively) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Tax Credits Effective Income Tax Rate Reconciliation, Tax Credit, Percent Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Variable Rate [Axis] Variable Rate [Axis] Platte River Power Authority - Unit Contingent Energy Platte River Power Authority [Member] Platte River Power Authority Business Segment Information Segment Reporting Disclosure [Text Block] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Regulatory liabilities, non-current Regulatory Liability, Noncurrent Regulatory Asset [Axis] Regulatory Asset [Axis] Schedule of Change in Asset Retirement Obligation Schedule of Change in Asset Retirement Obligation [Table Text Block] TC Colorado Solar, LLC TC Colorado Solar, LLC [Member] TC Colorado Solar, LLC Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Document Fiscal Year Focus Document Fiscal Year Focus Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Abstract] Variable Rate [Domain] Variable Rate [Domain] Additional Paid-in Capital Additional Paid-in Capital [Member] Gas distribution Gas Distribution Equipment [Member] Regulatory assets Regulatory assets Regulatory Assets Insurance Settlements Receivable, Noncurrent Insurance Settlements Receivable, Noncurrent 2027-2031 Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years Dividends on common stock (usd per share) Common Stock, Dividends, Per Share, Cash Paid Regulatory Accounting Public Utilities, Policy [Policy Text Block] Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset Environmental Remediation Site [Domain] Environmental Remediation Site [Domain] Other income (expense), net Other Nonoperating Income (Expense) Construction work in progress Public Utilities, Property, Plant and Equipment, Construction Work in Progress Senior Unsecured Notes Due 2030 Senior Unsecured Notes Due 2030 [Member] Senior Unsecured Notes Due 2030 Other investing activities Payments for (Proceeds from) Other Investing Activities Maximum Maximum [Member] Share-based Payment Arrangement [Abstract] Panhandle Eastern Pipe Line Panhandle Eastern Pipe Line [Member] Panhandle Eastern Pipe Line Guarantor Obligations by Nature [Axis] Guarantor Obligations, Nature [Axis] Electric Utilities Electric Utilities [Member] Electric Utilities Segment [Member] Total other assets, non-current Assets, Noncurrent, Other than Noncurrent Investments and Property, Plant and Equipment Power Generation Power Generation [Member] Power Generation Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] Schedule of Accrued Liabilities Schedule of Accrued Liabilities [Table Text Block] Award Type [Axis] Award Type [Axis] Arkansas Public Service Commission (APSC) Arkansas Public Service Commission (APSC) [Member] Arkansas Public Service Commission (APSC) Financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Senior Unsecured Notes Due 2027 Senior Unsecured Notes Due 2027 [Member] Senior Unsecured Notes Due 2027 [Member] Deferred taxes on AFUDC Allowance For Funds Used During Construction [Member] The offsetting entry to other income when an enterprise capitalizes, as part of the cost of plant and equipment, the cost of financing construction as financed partially by equity. Total stockholders’ equity Stockholders' Equity Attributable to Parent Accounts Receivable by Billing Status, Type [Axis] Billing Status, Type [Axis] Pueblo Airport Generation Pueblo Airport Generation [Member] Jointly Owned Pueblo Airport Generating Facility [Member] City Area Code City Area Code Contract Subject to Master Netting Arrangement Contract Subject to Master Netting Arrangement [Member] Contract Subject to Master Netting Arrangement [Member] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Senior Unsecured Notes Due 2026 Senior Unsecured Notes Due 2026 [Member] Senior Unsecured Notes Due 2026 [Member] Long-term Purchase Commitment, Period Long-term Purchase Commitment, Period Percent of recent average market price Common Stock Purchase Percentage of Recent Average Market Price Common stock purchase percentage of recent average market price Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Axis] Weighted average useful life Property, Plant and Equipment, Useful Life Equity: Stockholders' Equity Attributable to Parent [Abstract] Wyoming Electric Wyoming Electric [Member] Wyoming Electric [Member] Total Current Current Income Tax Expense (Benefit) Industrial Development Revenue Bonds Due 2021 Industrial Development Revenue Bonds Due 2021 [Member] Industrial Development Revenue Bonds Due 2021 [Member] Segment Reporting Information, Additional Information [Abstract] Segment Reporting Information, Additional Information [Abstract] Net periodic benefit expense Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Volatility range for the peer group, Maximum Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum Total amounts included in AOCI, after-tax not yet recognized as components of net periodic expense Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax Construction Work in Progress Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress Gas price derivatives Price Risk Derivative [Member] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Equity Compensation Share-based Payment Arrangement [Member] Lessee, Operating Lease, Term of Contract Lessee, Operating Lease, Term of Contract Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Total deferred tax liabilities Deferred Tax Liabilities, Gross Income Statement [Abstract] Income Statement [Abstract] Share Based Compensation Arrangement By Share Based Payment Award - Performance Period Used to Estimate Expected Share Payout Share Based Compensation Arrangement By Share Based Payment Award - Performance Period Used to Estimate Expected Share Payout Share Based Compensation Arrangement By Share Based Payment Award - Performance Period Used to Estimate Expected Share Payout Senior Unsecured Notes Due 2033 Senior Unsecured Notes Due 2033 [Member] Senior Unsecured Notes Due 2033 [Member] Entity Registrant Name Entity Registrant Name Asset Class [Domain] Asset Class [Domain] First Mortgage Bonds Due 2039 First Mortgage Bonds Due 2039 [Member] First Mortgage Bonds Due 2039 [Member] General Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment Plan participants’ contributions Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant Related Party Transaction [Axis] Related Party Transaction [Axis] Real Estate Real Estate [Member] Performance Share Award, Percentage of Target Share-based Compensation Arrangement by Share-based Payment Award, Payout, Percentage of Target The percentage target for payout of equity compensation awards Income tax (expense) Income Tax Expense (Benefit) Total Current and Deferred Income Tax Expense (Benefit) Income Tax Expense (Benefit) 2024 Defined Benefit Plan, Expected Future Benefit Payment, Year Three Accounts receivable, net Accounts Receivable, after Allowance for Credit Loss, Current Financing Receivable, Current, Allowance for Credit Loss Financing Receivable, Current, Allowance for Credit Loss [Table Text Block] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Entity Tax Identification Number Entity Tax Identification Number Retail Retail - Electric , Natural Gas and Coal [Member] Retail - Electric , Natural Gas and Coal Investment Type [Axis] Investment Type [Axis] Document Fiscal Period Focus Document Fiscal Period Focus Total current assets Current assets Assets, Current Jointly Owned Utility Plant Interests [Table] Jointly Owned Utility Plant Interests [Table] Shares Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Services transferred over time Transferred over Time [Member] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Total plant in service before construction work in progress Public Utilities, Property, Plant and Equipment Excluding Construction in Progress Public Utilities, Property, Plant and Equipment Excluding Construction in Progress Common Collective Trust, Equity Fund Common Collective Trust, Equity Fund [Member] Common Collective Trust, Equity Fund [Member] Current maturities of long-term debt Less current maturities Long-term Debt, Current Maturities Property, Plant and Equipment, Type [Domain] Long-Lived Tangible Asset [Domain] 2020-2022 Total Contract Capacity in Megawatts Due Per Year in Years Two and Three of the Contract Total Contract Capacity in Megawatts Due Per Year in Years Two and Three of the Contract Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Accounts receivable and other current assets Increase (Decrease) in Accounts Receivable and Other Operating Assets Winter Storm Uri Winter Storm Uri [Member] Winter Storm Uri Segment Reporting, Asset Reconciling Item Segment Reporting, Asset Reconciling Item [Line Items] Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Error Correction, Type [Domain] Error Correction, Type [Domain] Loss on reacquired debt Bond Issuance Costs [Member] Utility Bond Issuance Costs recoverable over the life of the original issue, or if refinanced, over the life of the new issue[Member] Equity Component [Domain] Equity Component [Domain] Other Stockholders' Equity, Other Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Carrying Costs Carrying Costs [Member] Carrying Costs Defined Contribution Plan, Company Retirement Defined Contribution Plan, Company Retirement [Member] The Company Retirement portion of the defined contribution plan in which there is no employee contribtuion required to receive a contribution. The contribution is based on a calculation of age and service. [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] Contingent Capacity Amounts on Wygen III Wygen III Generating Facility Wygen III Generating Facility [Member] Wygen III - Black Hills Power's coal-fired power generation plant that commenced operations on April 1, 2010.[Member] 2026 Unrecorded Unconditional Purchase Obligation, to be Paid, Year Five Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Schedule of Regulatory Assets and Liabilities Schedule of Regulatory Assets and Liabilities [Table Text Block] Schedule of Regulatory Assets and Liabilities Schedule of Allocation of Plan Assets Schedule of Allocation of Plan Assets [Table Text Block] Customer deposits and prepayments Customer Deposits and Prepayments Accrued Liabilities - Customer Deposits and Prepayments Valuation Allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent Schedule of Changes in Projected Benefit Obligations Schedule of Changes in Projected Benefit Obligations [Table Text Block] Long-term Purchase Commitment Long-term Purchase Commitment [Table Text Block] Weighted Average Weighted Average [Member] Natural Gas Indices [Axis] Natural Gas Indices [Axis] Natural Gas Indices [Axis] Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Fair Value, Inputs, Level 2 Fair Value, Inputs, Level 2 [Member] General Other Capitalized Property Plant and Equipment [Member] Auditor Location Auditor Location Derivative, Gain (Loss) on Derivative, Net Derivative, Gain (Loss) on Derivative, Net Finite-Lived Intangible Assets, Useful Life Finite-Lived Intangible Asset, Useful Life Commodity derivatives Commodity Contract Commodity Contract [Member] Flow-through adjustments Effective Income Tax Rate Reconciliation, Flow Through Accounting The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by Flow Through Accounting. Use of Estimates and Basis of Presentation Use of Estimates, Policy [Policy Text Block] Public Utilities, Approved Equity Capital Structure, Percentage Public Utilities, Approved Equity Capital Structure, Percentage Earnings Per Share of Common Stock Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Title of 12(b) Security Title of 12(b) Security Distributions to non-controlling interests Payments to Noncontrolling Interests Common stock, shares authorized Common Stock, Shares Authorized Ratio of Indebtedness to Net Capital Ratio of Indebtedness to Net Capital Document Type Document Type Volatility Rate - Historic Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate (comprised percent of historic volatility) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate (comprised percent of historic volatility) Number of Megawatts Capacity Purchased Number of Megawatts Capacity Purchased Number of Megawatts Capacity Purchased Product and Service [Domain] Product and Service [Domain] Nebraska Publc Service Commission (NPSC) Nebraska Publc Service Commission (NPSC) [Member] Nebraska Publc Service Commission (NPSC) Deferred energy and fuel cost adjustments Deferred energy and gas costs Deferred Fuel Costs [Member] 2022 Lessor, Operating Lease, Payment to be Received, Year Two M D U, Montana Dakota Utilities M D U, Montana Dakota Utilities [Member] MDU, Montana Dakota Utilities - utility that is an undivided owner of Wygen III[Member] Stated interest rate (percent) Debt Instrument, Interest Rate, Stated Percentage Uncertain Tax Benefits Effective Income Tax Rate Reconciliation, Uncertain Tax Benefits, Percent Effective Income Tax Rate Reconciliation, Uncertain Tax Benefits, Percent Thereafter Lessor, Operating Lease, Payment to be Received, after Year Five Net income attributable to non-controlling interest Less: comprehensive income attributable to non-controlling interest Net Income (Loss) Attributable to Noncontrolling Interest Benefit from Relieved TCJA Related Liabilities Benefit from Relieved TCJA Related Liabilities Benefit from Relieved TCJA Related Liabilities Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Revolving Credit Facility Revolving Credit Facility [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Derivative Assets, Current Derivative Assets, Current [Member] Line item in the statement of financial position in a classified presentation in which the fair value amounts of the derivative instruments are included. Non-controlling interest Effective Income Tax Rate Reconciliation, Noncontrolling Interest Income (Loss), Percent State and Local Jurisdiction State and Local Jurisdiction [Member] Sale of Stock, Price Per Share Sale of Stock, Price Per Share Unrecorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Unrecorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Long-term Contract for Purchase of Electric Power [Axis] Long-term Contract for Purchase of Electric Power [Axis] Hedging Relationship [Axis] Hedging Relationship [Axis] Stock Issued During Period, Shares, Treasury Stock Reissued Stock Issued During Period, Shares, Treasury Stock Reissued Interest Expense Interest Expense [Member] First Mortgage Bonds Due 2037 First Mortgage Bonds Due 2037 [Member] First Mortgage Bonds Due 2037 [Member] Guarantor Subsidiaries Guarantor Subsidiaries [Member] Subsequent Events Subsequent Events [Text Block] Other regulatory assets Other Regulatory Assets [Member] Other regulatory assets [Member] Investments Investment, Policy [Policy Text Block] Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities State tax credits Deferred Tax Assets, Tax Credit Carryforwards, Other Treasury stock at cost - 54,078 and 32,492, respectively Treasury Stock, Value Award vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Unrecognized Tax Benefits, Interest Expense Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense Jointly Owned Facilities Jointly Owned Facilities, Utility and Non-Regulated [Text Block] Disclosure of proportionate interests in jointly owned facilities (regulated utiliyt and non-regulated). Includes the amount of plants in service, the accumulated depreciation (if available), the amount of construction in progress, and the proportionate share. Includes statements that the amounts represent the company's share in each joint facility and that it must provide its own financing. States that the company's share of direct expenses of the joint facilities is included in the corresponding operating expenses on its income statement (for example, fuel, maintenance, other operating expense). [Text Block] Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] 2024 Unrecorded Unconditional Purchase Obligation Due Within Four Years Unrecorded Unconditional Purchase Obligation Due Within Four Years City of Colorado Springs City of Colorado Springs [Member] City of Colorado Springs Future Amortization Expense, Year Three Finite-Lived Intangible Asset, Expected Amortization, Year Three Surety Bond Surety Bond [Member] PacifiCorp Transmission PacifiCorp Transmission [Member] PacifiCorp Transmission [Member] Derivative [Table] Derivative [Table] Performance Share Units - Performance Condition Performance Share Units - Performance Condition [Member] Performance Share Units - Performance Condition El Paso - Bondad Station EP-Bondad Station [Member] EP-Bondad Station Revenue: Revenues [Abstract] Deferred tax liabilities: Deferred Tax Liabilities, Net [Abstract] Accrual for Environmental Loss Contingencies, Gross Accrual for Environmental Loss Contingencies, Gross Document Period End Date Document Period End Date Unusual or Infrequent Item, or Both [Domain] Unusual or Infrequent Item, or Both [Domain] Consolidated Entities [Domain] Consolidated Entities [Domain] State income tax (net of federal tax effect) Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent State Deferred State and Local Income Tax Expense (Benefit) Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] 2025 Unrecorded Unconditional Purchase Obligation, to be Paid, Year Four Debt Instrument, Term Debt Instrument, Term Income Statement Location [Domain] Income Statement Location [Domain] (Tax) benefit on reclassification adjustment of benefit plan liability - prior service cost Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, Tax Fuel Type [Domain] Fuel Type [Domain] Fuel Type Long-term Purchase Commitment [Line Items] Long-term Purchase Commitment [Line Items] Performance Shares, Equity Awards Performance Shares, Equity Awards [Member] The equity award components for Performance Shares [Member] Corporate Term Loan Due June 2021 Corporate Term Loan Due June 2021 [Member] Corporate Term Loan Due June 2021 [Member] Total property, plant and equipment, net Property, plant and equipment of variable interest entities, net Property, Plant and Equipment, Net Corriedale Wind Project Corriedale Wind Project [Member] Corriedale Wind Project [Member] Total operating expenses Operating Expenses Long-term debt - repayments Repayments of Long-term Debt Earnings per share of common stock: Earnings Per Share [Abstract] Property, plant and equipment Property, Plant and Equipment, Gross Performance Plan Payouts Performance Plan Payouts [Table Text Block] [Table Text Block] for Performance Plan Payouts [Table] Natural Gas Indices [Domain] Natural Gas Indices [Domain] [Domain] for Natural Gas Indices [Axis] Revenue Revenues Amounts reclassified from AOCI Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Cheyenne Prairie, Combined Cycle Cheyenne Prairie, Combined Cycle [Member] Cheyenne Prairie, Combined Cycle Excess deferred income taxes Deferred Income Tax Amortization [Member] Rate Action of a regulator resulting in return of prior period income tax over collections Error Correction, Other Error Correction, Other [Member] Asset Retirement Obligations [Table] Asset Retirement Obligations [Table] Asset Retirement Obligations [Table] Entity Current Reporting Status Entity Current Reporting Status Accounts payable and other current liabilities Increase (Decrease) in Other Accounts Payable and Accrued Liabilities Volatility range for peer group, Minimum Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum Defined Benefit Plan, Plan Assets, Amount Beginning fair value of plan assets Ending fair value of plan assets Defined Benefit Plan, Plan Assets, Amount Tri-State Generation and Transmission Association Tri-State Generation and Transmission Association [Member] Tri-State Generation and Transmission Association Effective Income Tax Rate, Continuing Operations Effective Income Tax Rate Reconciliation, Percent (Tax) benefit on benefit plan liability adjustments - prior service costs Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Tax Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Accounts Receivable, Trade Accounts Receivable, before Allowance for Credit Loss, Current Derivative, Nonmonetary Notional Amount Derivative, Nonmonetary Notional Amount Amortization expense for deferred financing costs Amortization of Debt Issuance Costs Unrecorded Unconditional Purchase Obligation [Line Items] Unrecorded Unconditional Purchase Obligation [Line Items] Regulatory assets, non-current Regulatory Assets, Noncurrent Fuel Type [Axis] Fuel Type [Axis] Generation Fuel Source, Wind, Coal, Solar Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] Federal Energy Regulatory Commission (FERC) Common Use System (CUS) Federal Energy Regulatory Commission (FERC) Common Use System (CUS) [Member] Federal Energy Regulatory Commission (FERC) Common Use System (CUS) [Member] Variable Interest Entity Variable Interest Entity Disclosure [Text Block] Unissued Shares Available Common Stock, Capital Shares Reserved for Future Issuance Valuation Allowance by Deferred Tax Asset [Axis] Valuation Allowance by Deferred Tax Asset [Axis] Income Taxes Income Tax, Policy [Policy Text Block] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Black Hills Electric Generation Black Hills Electric Generation [Member] Black Hills Electric Generation Entity Address, Postal Zip Code Entity Address, Postal Zip Code Gas transmission Gas Transmission Equipment [Member] Revenue from Contract with Customer Revenue from Contract with Customer [Policy Text Block] Diluted (in shares) Weighted average shares - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Income Taxes Income Tax Disclosure [Text Block] Related Party [Domain] Related Party [Domain] First Mortgage Bonds Due 2032 First Mortgage Bonds Due 2032 [Member] First Mortgage Bonds Due 2032 [Member] Services transferred at a point in time Transferred at Point in Time [Member] Plant acquisition adjustment Plant Acquisition Adjustment [Member] Plant Acquisition Costs Components of Net Periodic Benefit Cost Schedule of Net Benefit Costs [Table Text Block] Utility Plant, Megawatt Capacity Utility Plant, Megawatt Capacity Utility Plant, Megawatt Capacity Partnership Deferred Tax Assets, Investments Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Regulatory liabilities Increase (Decrease) in Regulatory Liabilities Class of Stock [Line Items] Class of Stock [Line Items] Name of Property [Axis] Name of Property [Axis] Not Designated as Hedging Instrument Not Designated as Hedging Instrument [Member] Credit Facility [Axis] Credit Facility [Axis] Entity Address, Address Line One Entity Address, Address Line One Unrecorded Unconditional Purchase Obligations Disclosure Unrecorded Unconditional Purchase Obligations Disclosure [Table Text Block] Less accumulated depreciation and depletion Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] AFUDC Borrowed Allowance for Funds Used During Construction, Capitalized Interest Principles of Consolidation Consolidation, Policy [Policy Text Block] Entity Shell Company Entity Shell Company Schedule of Short-term Debt Schedule of Short-term Debt [Table Text Block] Natural Gas Natural Gas [Member] Total current liabilities Current liabilities Liabilities, Current Intercompany Eliminations Intersegment Eliminations [Member] Wind Wind [Member] Electric Generation Source - Wind Supply Commitment [Axis] Supply Commitment [Axis] Public Utilities General Disclosures [Table] Public Utilities General Disclosures [Table] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Member] Business Group [Domain] Business Group [Domain] [Domain] for Business Group (grouping of segments) [Axis] Loss Contingencies [Table] Loss Contingencies [Table] Term Loan - borrowings Proceeds from Other Short-term Debt 2023-2028 Total Contract Capacity in Megawatts Due Per Year in Years Five Through Nine of the Contract Total Contract Capacity in Megawatts Due Per Year in Years Five Through Nine of the Contract Current Fiscal Year End Date Current Fiscal Year End Date Happy Jack Wind Purchase Power Agreement Happy Jack Wind Purchase Power Agreeement [Member] Happy Jack Wind Purchase Power Agreeement [Member] Intercompany Customers Intercompany Customers [Member] Intercompany Customers [Member] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Regulatory liabilities, current Regulatory liabilities, current Regulatory Liability, Current Statement [Table] Statement [Table] Global Settlement agreement with KCC Staff and various intervenors for a general rate increase and renewal of its safety and integrity rider. Global Settlement agreement with KCC Staff and various intervenors for a general rate increase and renewal of its safety and integrity rider. [Member] Global Settlement agreement with KCC Staff and various intervenors for a general rate increase and renewal of its safety and integrity rider. Accrual for Environmental Loss Contingencies - Pueblo Airport Generation Site Accrual for Environmental Loss Contingencies Investments Investment [Table Text Block] Recently Issued and Adopted Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Other deferred tax assets Deferred Tax Assets, Other 2026 Defined Benefit Plan, Expected Future Benefit Payment, Year Five Unrecognized compensation expense Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Public Utilities, Requested Rate Increase (Decrease), Amount Public Utilities, Requested Rate Increase (Decrease), Amount Statistical Measurement [Axis] Statistical Measurement [Axis] Accounts Receivable and Allowance for Credit Losses Accounts Receivable [Policy Text Block] Subsequent Event Subsequent Event [Member] Goodwill Goodwill Liabilities Settled Asset Retirement Obligation, Liabilities Settled Solar Solar [Member] Electric Generation Source - Solar Goodwill Schedule of Goodwill [Table Text Block] 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] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Long-term Contract for Purchase of Electric Power, Share of Plant Output Being Purchased Long-term Contract for Purchase of Electric Power, Share of Plant Output Being Purchased Schedule of Derivative Instruments in Statement of Financial Position, Fair Value Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Accumulated Defined Benefit Plans Adjustment Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent Purchased Gas Cost Obligation Purchased Gas Cost Obligation [Member] Purchased Gas Cost Obligation [Member] Deferred income taxes Total Deferred Deferred Income Tax Expense (Benefit) Investment [Line Items] Investment Holdings [Line Items] Hedging Designation [Domain] Hedging Designation [Domain] Black Hills Electric Generation and Colorado Electric Black Hills Electric Generation and Colorado Electric [Member] Black Hills Electric Generation and Colorado Electric [Member] Federal Statutory Rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Earnings per Share of Common Stock Earnings Per Share, Policy [Policy Text Block] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Net income available for common stock Net income available for common stock Net Income (Loss) Attributable to Parent Kansas Corporation Commission (KCC) Kansas Corporation Commission (KCC) [Member] Kansas Corporation Commission (KCC) Contract or notional amounts and terms of marketing activities and derivative commodity instruments Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Federal NOL (a) Deferred Tax Assets, Operating Loss Carryforwards Unrecorded Unconditional Purchase Obligation [Table] Unrecorded Unconditional Purchase Obligation [Table] Interest cost Defined Benefit Plan, Interest Cost Accrued employee compensation, benefits and withholdings Employee-related Liabilities, Current Performance Goal - Percentile of Peer Group Performance Share-based Compensation Arrangement by Share Based Payment Award, Performance Goal - Percentile of Peer Group Performance Share-based Compensation Arrangement by Share Based Payment Award, Performance Goal - The Company's Total Shareholder Return for the Prescribed Period as a Percentile of Peer Group Performance Iowa Utilities Board (IUB) Iowa Utilities Board (IUB) [Member] Iowa Utilities Board (IUB) Income Statement Location [Axis] Income Statement Location [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Schedule of Maturities of Long-term Debt Schedule of Maturities of Long-term Debt [Table Text Block] Segment Reporting Segment Reporting, Policy [Policy Text Block] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Performance Share Units - Market Condition Performance Share Units - Market Condition [Member] Performance Share Units - Market Condition Return Seeking Assets Return Seeking Assets [Member] Return Seeking Assets - Consisting of Equity Securities, Real Estate, Fixed Income Funds and Cash Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Public Utilities, Approved Return on Equity, Percentage Public Utilities, Approved Return on Equity, Percentage Net borrowings (payments) of Revolving Credit Facility and CP Program Net borrowings (payments) of Revolving Credit Facility and CP Program Net borrowings (payments) of Revolving Credit Facility and CP Program Other assets, non-current Other Assets, Noncurrent Commercial Paper, Maximum Borrowing Capacity Commercial Paper, Maximum Borrowing Capacity Commercial Paper, Maximum Borrowing Capacity Transmission Public Utilities, Property, Plant and Equipment, Transmission Post-65 Ultimate trend rate - Black Hills Corp Defined Benefit Plan, Ultimate Health Care Cost Trend Rate Expected return on assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Segments [Axis] Segments [Axis] Non-controlling interest Noncontrolling Interest in Variable Interest Entity Defined Contribution Plan, Employee Vesting Period Defined Contribution Plan, Employee Vesting Period Period over which an employee vests in a defined contribution plan. Retirement Benefits [Abstract] Entity File Number Entity File Number Postretirement Health Coverage Postretirement Health Coverage [Member] Restricted Net Assets for Subsidiaries Amount of Restricted Net Assets for Consolidated and Unconsolidated Subsidiaries Energy [Domain] Energy [Domain] Stockholders’ equity - Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract] Operations and maintenance Operating Expense, Maintenance, Operations, and Other Costs and Expense Amount of operating expenses for the period including selling, general, and administrative expenses, costs include routine repairs and maintenance and operations. Public Utilities, Approved Debt Capital Structure, Percentage Public Utilities, Approved Debt Capital Structure, Percentage Defined Contribution Plan Retirement Plan Name [Domain] Transaction [Domain] Transaction [Domain] Deferred Financing Costs Deferred Financing Costs [Table Text Block] Schedule of Deferred Financing Costs expensed on the Statement of Income and/or net amount presented on the Statement of Financial Position [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Benefit plan liability adjustments - net gain (loss) (net of tax of $(664), $191 and $1,886, respectively) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax Black Hills Service Company Black Hills Service Company [Member] Black Hills Service Company [Member] Rate Review Approved by Regulatory Agency Rate Review Approved by Regulatory Agency [Member] Rate Review Approved by Regulatory Agency Private Placement Private Placement [Member] Restricted Stock and RSUs, total fair value of shares vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Granted (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Investment income (loss) Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Ownership Share Percentage Jointly Owned Utility Plant, Proportionate Ownership Share Jointly Owned Utility Plant, Proportionate Ownership Share Benefit plan liabilities Liability, Defined Benefit Plan, Noncurrent Credit Facility [Domain] Credit Facility [Domain] Schedule of Guarantor Obligations Schedule of Guarantor Obligations [Table Text Block] ASSETS Assets [Abstract] 2024 Long-Term Debt, Maturity, Year Three Risk Management And Derivatives Derivative Instruments and Hedging Activities Disclosure [Text Block] Performance Shares, Granted in Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Natural Gas, Distribution Natural Gas, Distribution [Member] Natural Gas for distribution [Member] Property, Plant and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Long-Term Contract for Transmission of Electric Power [Axis] Long-Term Contract for Transmission of Electric Power [Axis] Long-Term Contract for Transmission of Electric Power Amount of Payroll Tax (Social Security Employment Tax) Deferral Allowed Under the CARES Act Amount of Payroll Tax (Social Security Employment Tax) Deferral Allowed Under the CARES Act Amount of Payroll Tax (Social Security Employment Tax) Deferral Allowed Under the CARES Act Debt Instrument [Axis] Debt Instrument [Axis] Employee benefit plans and related deferred taxes Employee benefit plan costs and related deferred taxes Pension and Other Postretirement Plans Costs [Member] Accretion Asset Retirement Obligation, Accretion Expense Deferred credits and other liabilities: Liabilities, Noncurrent [Abstract] Black Hills Energy, Wyoming Electric Black Hills Energy, Wyoming Electric [Member] Black Hills Energy, Wyoming Electric [Member] Related Party [Axis] Related Party [Axis] Net amortization of prior service cost Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Weighted Average Grant Date Fair Value (usd per share) Weighted Average Grant Date of Fair Value Share-Based Compensation Arrangement Weighted average fair value at grant date for non-vested equity-based awards issued during the period. Fuel, purchased power and cost of natural gas sold Fuel, purchased power and cost of natural gas sold Fuel, Purchased Power and Cost of Gas Sold Fuel costs incurred that are directly related to goods produced and sold and services rendered during the reporting period, combined with the amount of purchased power charged against earnings for the period, and cost of gas sold to customers for the period. Schedule of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Tax Credit Carryforward [Table] Tax Credit Carryforward [Table] Long-term Contract for Purchase of Electric Power [Domain] Long-term Contract for Purchase of Electric Power [Domain] Amount Recovered Through Regulatory Mechanism Amount Recovered Through Regulatory Mechanism Amount Recovered Through Regulatory Mechanism Long-term Purchase Commitment, Category of Item Purchased [Domain] Long-term Purchase Commitment, Category of Item Purchased [Domain] Gross Payroll Tax Credits Recognized (Cares Act) Gross Payroll Tax Credits Recognized (Cares Act) Gross Payroll Tax Credits Recognized upon the completion of the Cares Act employee retention tax credits study Plant acquisition adjustment Public Utilities, Property, Plant and Equipment, Amount of Acquisition Adjustments Purchase Power Agreement Set to Expire after a Certain Number of Years Following Completion of the Facility Purchase Power Agreement Set to Expire after a Certain Number of Years Following Completion of the Facility Purchase Power Agreement Set to Expire after a Certain Number of Years Following Completion of the Facility Transmission Tie Transmission Tie [Member] Jointly onwed Transmission Tie [Member] Schedule of Employer Contribution to Employee Benefit Plans Schedule of Employer Contribution to Employee Benefit Plans [Table Text Block] Schedule of Employer Contribution to Defined Benefit and Defined Contribution Plans [Table Text Block] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] 2026 Long-Term Debt, Maturity, Year Five Schedule of Nonvested Share Activity Schedule of Nonvested Share Activity [Table Text Block] Power purchased Power Purchased [Member] Power Purchased [Member] Assets Held For Sale Used to Acquire Other Investments Assets Used to Acquire Other Investments Assets Used to Acquire Other Investments Credit Carryovers Deferred Tax Assets, Tax Credit Carryforwards Performance Shares, Number of Shares Authorized Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Regulatory Matters Schedule of Regulatory Assets and Liabilities [Text Block] Recoveries and Other Additions Accounts Receivable, Allowance for Credit Loss, Recovery Hedge Funds Hedge Funds, Multi-strategy [Member] Number of Days Following the End of the Quarter When Distributions of Net Income Attributable to this Non-controlling Interest are Due Number of Days Following the End of the Quarter When Distributions of Net Income Attributable to this Non-controlling Interest are Due Number of Days Following the End of the Quarter When Distributions of Net Income Attributable to this Non-controlling Interest are Due Credit Facility and Short Term Debt Covenants Credit Facility and Short Term Debt Covenants [Table Text Block] Credit Facility and Short Term Debt Covenants Public Utilities, Requested Return on Equity, Percentage Public Utilities, Requested Return on Equity, Percentage Regulatory assets, current Regulatory assets, current Regulatory Assets, Current Wholesale Wholesale [Member] Wholesale [Member] 2025 Lessor, Operating Lease, Payment to be Received, Year Five Depreciation, depletion and amortization, remaining amortization period Depreciation, Depletion And Amortization, Remaining Amortization Period The depreciation, depletion or amortization period remaining on an asset. 2022 Unrecorded Unconditional Purchase Obligation Due Within Two Years Unrecorded Unconditional Purchase Obligation Due Within Two Years Additions Charged to Costs and Expenses Accounts Receivable, Credit Loss Expense (Reversal) Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Long-term debt Long-term Debt, Gross Derivative Assets, Total Assets, Fair Value Disclosure Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Settlement agreement reached with CPUC Staff and various intervenors, subject to the review and approval by an Administrative Law Judge and the CPUC. Settlement agreement reached with CPUC Staff and various intervenors, subject to the review and approval by an Administrative Law Judge and the CPUC. [Member] Settlement agreement reached with CPUC Staff and various intervenors, subject to the review and approval by an Administrative Law Judge and the CPUC. TOTAL LIABILITIES AND TOTAL EQUITY Liabilities and Equity Other tax differences Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Other (none of which is individually significant) Other Accrued Liabilities, Current Impairment of investment Impairment of investment Other Asset Impairment Charges Lessor, Operating Lease, Payments to be Received Lessor, Operating Lease, Payments to be Received Defined Benefit Plan, Plan Assets, Benefits Paid Defined Benefit Plan, Plan Assets, Benefits Paid Defined Contribution Plan, 401K Defined Contribution Plan, 401K [Member] The 401K defined contribution plan, which requires a contribution from the employee in order to receive a matching contribution (within limits) from the employer [Member] Senior Unsecured Notes Due 2029 Senior Unsecured Notes Due 2029 [Member] Senior Unsecured Notes Due 2029 [Member] Environmental Remediation Site [Axis] Environmental Remediation Site [Axis] Derivative [Line Items] Derivative [Line Items] Public Utilities Term of Power Purchase Agreement Public Utilities Term of Power Purchase Agreement Public Utilities Term of Power Purchase Agreement Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Operating expenses: Operating Expenses [Abstract] Enable East Pipeline Enable East Pipeline [Member] Enable East Pipeline 2023 Defined Benefit Plan, Expected Future Benefit Payment, Year Two Regulatory liabilities Regulatory liabilities Regulatory Liabilities Energy Related Derivative Energy Related Derivative [Member] Minimum Minimum [Member] Error Correction, Type [Axis] Error Correction, Type [Axis] Other operating activities, net Increase (Decrease) in Other Operating Assets and Liabilities, Net City Of Gillette City Of Gillette [Member] City Of Gillette, Wyoming, an undivided owner in Wygen III [Member] Cheyenne Prairie, Simple-Cycle Combustion Turbine Cheyenne Prairie, Simple-Cycle Combustion Turbine [Member] Cheyenne Prairie, Simple-Cycle Combustion Turbine Derivative Liabilities, Total Financial and Nonfinancial Liabilities, Fair Value Disclosure Income before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Less unamortized deferred financing costs Deferred Financing Costs Debt Issuance Costs, Net Natural Gas Physical Purchases Natural Gas Physical Purchases [Member] Natural Gas Physical Purchases [Member] Preferred Stock, Shares Authorized Preferred Stock, Shares Authorized Settlement of Plan to Provide TCJA and State Tax Reform benefits to Customers Annually Settlement of Plan to Provide TCJA and State Tax Reform benefits to Customers Annually Settlement of Plan to Provide TCJA and State Tax Reform benefits to Customers Annually Common Collective Trust, Cash And Cash Equivalents Common Collective Trust, Cash And Cash Equivalents [Member] Common Collective Trust, Cash And Cash Equivalents [Member] Blended volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Weighted Average Volatility Rate First Mortgage Bonds Due 2044 First Mortgage Bonds Due 2044 [Member] First Mortgage Bonds Due 2044 [Member] Cumulative Effect, Period of Adoption [Axis] Cumulative Effect, Period of Adoption [Axis] Other assets: Other Assets, Noncurrent [Abstract] Interest Rate Swap and Commodity Derivative Interest Rate Swap and Commodity Derivative [Member] Interest Rate Swap and Commodity Derivative 2025 Long-Term Debt, Maturity, Year Four Issuance of common stock Stock Issued During Period, Value, New Issues Cash and cash equivalents: Cash and Cash Equivalents, Period Increase (Decrease) [Abstract] Financing Debt Disclosure [Text Block] Schedule of Components of Income Tax Expense (Benefit) Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Line of Credit Line of Credit [Member] Share-based Compensation Plans Share-based Payment Arrangement [Text Block] Fair Value, Inputs, Level 3 Fair Value, Inputs, Level 3 [Member] Natural gas transportation and storage agreements Transportation, Storage, Gathering And Coal Agreements [Member] Transportation, Storage, Gathering And Coal Agreements [Member] Purchase Power Contract, MEAN, for up to 20 Megawatts Purchase Power Contract, MEAN Purchase Power Contract, MEAN [Member] Long-term Purchase Power Contract with MEAN Derivative Liabilities, Noncurrent Derivative Liabilities, Noncurrent [Member] Line item in the statement of financial position in a classified presentation in which the fair value amounts of the derivative instruments are included. Production, processing and storage Public Utilities, Property, Plant and Equipment, Generation or Processing Payments of Stock Issuance Costs Payments of Stock Issuance Costs Issuance of common stock (in shares) Stock Issued During Period, Shares, New Issues Senior Unsecured Notes Due 2024 Senior Unsecured Notes Due 2024 [Member] Senior Unsecured Notes Due 2024 2024 Lessor, Operating Lease, Payment to be Received, Year Four Gas supply contract termination Gas Supply Contract Termination [Member] Gas Supply Contract Termination [Member] Letters of Credit Outstanding, Amount Letters of Credit Outstanding, Amount Public Utilities, Regulatory Proceeding [Domain] Public Utilities, Regulatory Proceeding [Domain] Audit Information [Abstract] Audit Information [Abstract] Total other income (expense) Nonoperating Income (Expense) Inventory, Net [Abstract] Inventory, Net [Abstract] Number Of One-Year Extension Options Number Of One-Year Extension Options Number Of One-Year Extension Options Capital Addition Requirements by the FERC Joint-Access Transmission Tariff Capital Addition Requirements by the FERC Joint-Access Transmission Tariff Capital Addition Requirements by the FERC Joint-Access Transmission Tariff Performance Shares Performance Shares [Member] Other Postretirement Benefits Plan Other Postretirement Benefits Plan [Member] Public Utilities, Approved Rate Increase (Decrease), Amount Public Utilities, Approved Rate Increase (Decrease), Amount Commitments, contingencies and guarantees (Note 3) Commitments and Contingencies Net unrealized gains (losses) on commodity derivatives (net of tax of $(980), $14 and $126, respectively) Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments, Tax 2025 Unrecorded Unconditional Purchase Obligation Due Within Five Years Unrecorded Unconditional Purchase Obligation Due Within Five Years Subsequent Event [Table] Subsequent Event [Table] AFUDC Equity Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Emerging Growth Company Entity Emerging Growth Company Supply Commitment Arrangement [Domain] Supply Commitment Arrangement [Domain] Allowance for credit losses Accounts Receivable, Allowance for Credit Loss, Current Accounts Receivable, Allowance for Credit Loss, Current Accounts Receivable, Allowance for Credit Loss, Current Senior Unsecured Notes Due 2023 Senior Unsecured Notes Due 2023 [Member] Senior Unsecured Notes Due 2023 [Member] Black Hills Corporation Black Hills Corporation [Member] Black Hills Corporation [Member] Restricted Stock Restricted Stock [Member] Billed Revenues Billed Revenues [Member] Fixed for Float Swaps Purchased Fixed for Float Swaps Purchased [Member] Fixed for Float Swaps Purchased [Member] Proceeds from Issuance of Debt Proceeds from Issuance of Debt Auditor Name Auditor Name Cover [Abstract] Operations and maintenance, including taxes Costs and Expenses Natural Gas Purchases Unrecorded Unconditional Purchase Obligation, Purchases Other comprehensive income (loss), before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Treasury stock, shares Treasury Stock, Shares (Tax) benefit on benefit plan liability adjustments - net gain (loss) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax Rate of increase in compensation levels Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Netting Contract by Category [Domain] Netting Contract, Category [Domain] [Domain] for Netting Contract by Category [Axis] Electricity Electricity [Member] Schedule of Net Periodic Benefit Cost Not yet Recognized Schedule of Net Periodic Benefit Cost Not yet Recognized [Table Text Block] 2024 Unrecorded Unconditional Purchase Obligation, to be Paid, Year Three Increase in capitalized assets associated with asset retirement obligations Non-cash Revision to Capitalized Asset Retirement Costs The amount of non-cash revision to property, plant and equipment for capitalized asset retirement costs Rate Review Filed with the Regulatory Agency Rate Review Filed with the Regulatory Agency [Member] Rate Review Filed with the Regulatory Agency [Member] Short-term Debt [Line Items] Short-term Debt [Line Items] Platte River Power Authority Wind Power Agreement Platte River Power Authority Wind Power Agreement [Member] Platte River Power Authority Wind Power Agreement [Member] Dividends paid on common stock Payments of Dividends Current: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Defined Benefit Plan Assumptions Used In Calculating Net Periodic Benefit Cost Expected Rate of Return On Assets For Next Fiscal Year Defined Benefit Plan Assumptions Used In Calculating Net Periodic Benefit Cost Expected Rate of Return On Assets For Next Fiscal Year An assumption for the next fiscal year as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract] Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract] Carrying Amount Reported Value Measurement [Member] El Paso - San Juan Basin EP-San Juan Basin [Member] EP-San Juan Basin Volatility Rate - Implied Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate (comprised percent of implied volatility) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate (comprised percent of implied volatility) Common Stock Common Stock [Member] Interest income Investment Income, Interest Production, Electric Electric Generation Equipment [Member] Operating income Operating income Operating Income (Loss) Defined Contribution Plan, Employer Discretionary Contribution Amount Defined Contribution Plan, Employer Discretionary Contribution Amount Plant in Service Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service Manufactured Gas Plant Manufactured Gas Plant [Member] Manufactured Gas Plant [Member] Regulatory assets Increase (Decrease) in Other Regulatory Assets Business Description and Significant Accounting Policies Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Future Amortization Expense, Year Two Finite-Lived Intangible Asset, Expected Amortization, Year Two Hedging Designation [Axis] Hedging Designation [Axis] Over the Counter Over the Counter [Member] Stock compensation Share-based Payment Arrangement, Noncash Expense Regulatory assets (a) Deferred Tax Liabilities, Regulatory Assets Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Treasury Stock Treasury Stock [Member] Long-Term Contract for Transmission of Electric Power [Domain] Long-Term Contract for Transmission of Electric Power [Domain] Long-Term Contract for Transmission of Electric Power Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] Regulatory Asset, Amortization Period Regulatory Asset, Amortization Period Gas Utilities Gas Utilities [Member] Gas Utilities [Member] Annual Revenue Requirement, as Required by the FERC Joint-Access Transmission Tariff Annual Revenue Requirement, as Required by the FERC Joint-Access Transmission Tariff Annual Revenue Requirement, as Required by the FERC Joint-Access Transmission Tariff Less Accumulated Depreciation Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Number of Megawatts Capacity Sold Number of Megawatts Capacity Sold Number of Megawatts Capacity Sold Property, plant and equipment additions Payments to Acquire Property, Plant, and Equipment Tax Credit Carryforward, Valuation Allowance Tax Credit Carryforward, Valuation Allowance Performance Share Award Payout, Cash Percentage Share Based Compensation Arrangement By Share Based Payment Award, Payout, Cash Percentage Percentage of performance based compensation to be paid out in cash. Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Defined Benefit Plan, Accumulated Benefit Obligation Defined Benefit Plan, Accumulated Benefit Obligation Employer contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Line of Credit Facility, Interest Rate at Period End Line of Credit Facility, Interest Rate at Period End Unbilled Revenues Unbilled Revenues [Member] At The Market Equity Offering Program Authorized Aggregate Value At The Market Equity Offering Program Authorized Aggregate Value At The Market Equity Offering Program authorized an aggregate value that the Company may, through its sales agents, offer and sell from time to time shares of its common stock. Prepayment penalty Payment for Debt Extinguishment or Debt Prepayment Cost Deferred Tax Assets, Net [Abstract] Deferred Tax Assets, Net [Abstract] Future Amortization Expense, Year One Finite-Lived Intangible Asset, Expected Amortization, Year One At The Market Equity Program Proceeds from Sale of Stock At The Market Equity Program Proceeds from Sale of Stock At The Market Equity Program Proceeds from Sale of Stock Consolidation Items [Axis] Consolidation Items [Axis] Operating Loss Carryforwards Operating Loss Carryforwards Common stock, shares, issued Common Stock, Shares, Issued Schedule of Changes in Fair Value of Plan Assets Schedule of Changes in Fair Value of Plan Assets [Table Text Block] Plant Net of Accumulated Depreciation Jointly Owned Utility Plant, Net Ownership Amount Investment [Table] Investment Holdings [Table] Schedule of Assumptions Used Defined Benefit Plan, Assumptions [Table Text Block] Entity Address, City or Town Entity Address, City or Town Black Hills Energy - Iowa Gas Black Hills Energy - Iowa Gas [Member] Black Hills Energy - Iowa Gas Variable Interest Entities Consolidation, Variable Interest Entity, Policy [Policy Text Block] Eurodollar Eurodollar [Member] Schedule of Expected Benefit Payments Schedule of Expected Benefit Payments [Table Text Block] Federal Energy Regulatory Commission (FERC) Federal Energy Regulatory Commission (FERC) [Member] Federal Energy Regulatory Commission (FERC) [Member] Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Gas, Storage Natural Gas, Storage [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Other Comprehensive Income Comprehensive Income (Loss) Note [Text Block] Schedule of Short-term Debt [Table] Schedule of Short-term Debt [Table] Measurement Frequency [Domain] Measurement Frequency [Domain] Jointly Owned Utility Plant [Axis] Jointly Owned Utility Plant [Axis] Defined Benefit Plan, Fair Value of Plan Assets, Excluding Net Asset Value investments Defined Benefit Plan, Fair Value of Plan Assets, Excluding Net Asset Value investments Defined Benefit Plan, Fair Value of Plan Assets, Excluding Net Asset Value investments Interest expense Interest Expense Deferred: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Expected long-term rate of return on assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year One Retained earnings Retained Earnings (Accumulated Deficit) Beginning Balance Ending Balance Asset Retirement Obligation Accrued property taxes Accrual for Taxes Other than Income Taxes, Current Fuel Energy Related Inventory, Other Fossil Fuel Statement of Stockholders' Equity [Abstract] Entity Filer Category Entity Filer Category Common Collective Trust, Fixed Income Fund Common Collective Trust, Fixed Income Fund [Member] Common Collective Trued, Fixed Income Fund [Member] Power purchase and transmission services agreements Power Purchase Agreements [Member] Power Purchase Agreements [Member] PacifiCorp Purchase Power Agreement PacifiCorp Purchase Power Agreement [Member] PacifiCorp PPA [Member] Three-year risk-free rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Derivative Instruments, Gain (Loss) Derivative Instruments, Gain (Loss) [Table Text Block] Fair Value Fair Value Estimate of Fair Value Measurement [Member] Asset Retirement Obligations Asset Retirement Obligation Disclosure [Text Block] Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments Gas Price Derivatives - Term of Contract Derivative, Term of Contract Total equity Beginning balance Ending balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Summary of State Tax Carryforwards Summary of Tax Credit Carryforwards [Table Text Block] Amendment Flag Amendment Flag Long-term debt - issuance Proceeds from Issuance of Long-term Debt Equity Components [Axis] Equity Components [Axis] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Antidilutive Securities Excluded from Computation of Earnings Per Share, by Antidilutive Securities [Axis] Antidilutive Securities [Axis] Operating Loss Carryforwards, With no Expiration Date Operating Loss Carryforwards, With no Expiration Date Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. Operating Loss Carryforwards, With no Expiration Date Cash Flow Hedging Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] Sale of Stock [Domain] Sale of Stock [Domain] Other investments Investments [Member] Other regulatory liabilities Other Regulatory Liabilities [Member] Other regulatory liabilities [Member] Materials, supplies and fuel Total materials, supplies and fuel Inventory, Net Receivables Billing Status [Domain] Receivables Billing Status [Domain] Segment information included in Consolidated Statements of Income Schedule of Segment Reporting Information, by Segment [Table Text Block] Payment for Pension and Other Postretirement Benefits Payment for Other Postretirement Benefits Black Hills Energy - Colorado Gas Black Hills Energy, Colorado Gas [Member] Black Hills Energy, Colorado Gas [Member] Federal Deferred Federal Income Tax Expense (Benefit) Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Contingent Capacity Amounts on Neil Simpson II Neil Simpson I I [Member] Neil Simpson II power generation faciltiy located near Gillette WY [Member] Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Product and Service [Axis] Product and Service [Axis] Jointly Owned Utility Plant [Domain] Jointly Owned Utility Plant [Domain] Deferred gas cost adjustments Asset Recoverable Gas Costs [Member] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Accounts Receivable, Allowance for Credit Loss [Roll Forward] At The Market Equity Offering Program Shares Issued At The Market Equity Offering Program Shares Issued At The Market Equity Offering Program Shares Issued Entity Public Float Entity Public Float Documents Incorporated by Reference Documents Incorporated by Reference [Text Block] Performance Share Award Payout, Shares of Common Stock Percentage Share Based Compensation Arrangement By Share Based Payment Award, Payout, Shares Percentage Payout percentage for share based compensation to be issued in shares of common stock. Share-based compensation (in shares) Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] 2023 Unrecorded Unconditional Purchase Obligation Due Within Three Years Unrecorded Unconditional Purchase Obligation Due Within Three Years Schedule of Jointly Owned Utility Plants Schedule Of Jointly Owned Facilities [Table Text Block] Tabular disclosure of proportionate interests in jointly owned plants. Includes the amount of plants in service, the accumulated provision for depreciation (if available), the amount of facilities under construction, and the proportionate share. Includes statements that the amounts represent the company's share in each joint plant and that it must provide its own financing. Information concerning two or more plants on the same site may be combined. States that the company's share of direct expenses of the joint facilities is included in the corresponding operating expenses on its income statement (for example, maintenance and other operating expense). This schedule includes both Utility and non-Utility facilities. [Table Text Block] Statement [Line Items] Statement [Line Items] Category of Item Purchased [Axis] Category of Item Purchased [Axis] Senior Unsecured Notes Due 2046 Senior Unsecured Notes Due 2046 [Member] Senior Unsecured Notes Due 2046 [Member] Share-based compensation Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture Defined Benefit Plans Retirement Plan Type [Domain] Debt Covenants [Abstract] Debt Disclosure [Abstract] Disclosure of Share-based Compensation Arrangements by Share-based Payment Award Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] Schedule of Health Care Cost Trend Rates Schedule of Health Care Cost Trend Rates [Table Text Block] Property, Plant and Equipment, Type [Axis] Long-Lived Tangible Asset [Axis] Less: Valuation allowance Deferred Tax Assets, Valuation Allowance Corporate, Non-Segment Corporate, Non-Segment [Member] Number of Defined Pension Plans Number of Defined Pension Plans Number of Defined Pension Plans Customer [Axis] Customer [Axis] Employee Benefit Plans Retirement Benefits [Text Block] Electric distribution Electric Distribution [Member] Asset Class [Axis] Asset Class [Axis] Document Annual Report Document Annual Report Share-based Payment Arrangement, Expensed Amount Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months Benefit plan liability adjustments - prior service costs (net of tax of $0, $0 and $2 respectively) Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), after Tax Common stock issued Proceeds from Issuance of Common Stock TOTAL ASSETS Total Assets Assets Plan Name [Domain] Plan Name [Domain] Kern River - Opal Kern River - Opal [Member] Kern River - Opal Decommissioning costs Environmental Restoration Costs [Member] Interest (net of amounts capitalized) Interest Paid, Excluding Capitalized Interest, Operating Activities Adjusted operating income (loss) Adjusted Operating Income (Loss) Adjusted Operating Income (Loss) Noncontrolling Interest Noncontrolling Interest [Member] Guarantor Obligations [Line Items] Guarantor Obligations [Line Items] 2021 Unrecorded Unconditional Purchase Obligation, Due in the Next Twelve Months Unrecorded Unconditional Purchase Obligation, Due in the Next Twelve Months Accounts Receivable and Allowance for Doubtful Accounts Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Derivative Contract [Domain] Derivative Contract [Domain] Derivative Contract [Domain] Cumulative Effect, Period of Adoption [Domain] Cumulative Effect, Period of Adoption [Domain] Net cash provided by (used in) operating activities Net Cash Provided by (Used in) Operating Activities Notes payable Short-term Debt Total long-term debt Long Term Debt Before The Deduction Of Deferred Financing Costs Amount of long term debt before the deduction of deferred financing costs, but after the deduction of unamortized (discount) premium and includes current maturities. Accounts Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Cushion gas - not depreciable Cushion Gas - Not Depreciated [Member] Cushion Gas - Not Depreciated [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Business Group [Axis] Business Group [Axis] Business Group (grouping of segments) [Axis] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Subsequent Event [Line Items] Subsequent Event [Line Items] Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Defined Benefit Plan, Alternative Investments, Fair Value Of Plan Assets Defined Benefit Plan, Alternative Investments, Fair Value Of Plan Assets Defined Benefit Plan, Alternative Investments, Fair Value Of Plan Assets Basic (in shares) Weighted average shares - Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Earnings per share, Diluted (usd per share) Total earnings (loss) per share of common stock, Diluted (usd per share) Earnings Per Share, Diluted Segments [Domain] Reporting Segment [Domain] Segments [Domain] Deferred financing cost amortization Amortization of Debt Issuance Costs and Discounts Service Cost Defined Benefit Plan, Service Cost 2023 Unrecorded Unconditional Purchase Obligation, to be Paid, Year Two Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Income taxes Income Taxes Paid, Net Thereafter Unrecorded Unconditional Purchase Obligation Due after Five Years a Unrecorded Unconditional Purchase Obligation Due after Five Years Intangible assets, net Intangible assets, net, beginning balance Intangible assets, net, ending balance Intangible Assets, Net (Excluding Goodwill) Comprehensive income available for common stock Comprehensive Income (Loss), Net of Tax, Attributable to Parent Trend Year Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate Regulatory Liability [Domain] Regulatory Liability [Domain] Other comprehensive income (loss), net of tax: Other Comprehensive Income (Loss), Net of Tax [Abstract] Schedule of Amounts Recognized in Balance Sheet Schedule of Amounts Recognized in Balance Sheet [Table Text Block] Deferred Financing Costs Debt, Policy [Policy Text Block] Deferred income tax liabilities, net Deferred Income Tax Liabilities, Net Derivative Asset, Fair Value, Amount Not Offset Against Collateral Derivative Asset, Fair Value, Amount Not Offset Against Collateral Collateral Already Posted, Aggregate Fair Value Collateral Already Posted, Aggregate Fair Value Natural gas in storage Energy Related Inventory, Natural Gas in Storage Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Variable Interest Entity, Primary Beneficiary Variable Interest Entity, Primary Beneficiary [Member] Accounts payable Accounts Payable, Current Depreciation, depletion and amortization Depreciation, Depletion and Amortization Energy [Axis] Energy [Axis] TCJA bill credits Effective Income Tax Reconciliation, TCJA-Related Customer Billing Credits to its Customers, Percent Effective Income Tax Reconciliation, TCJA-Related Customer Billing Credits to its Customers, Percent Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Coal Coal [Member] Electric Genearation Source - Coal Environmental Environmental [Member] Environmental costs associated with utility property [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Materials, supplies and fuel Increase (Decrease) in Inventories Beginning balance (in shares) Ending balance (in shares) Common Stock, Shares, Outstanding Colorado Public Utilities Commission (CPUC) Colorado Public Utilities Commission (CPUC) [Member] Colorado Public Utilities Commission (CPUC) [Member] Investments Long-term Investments Materials and supplies Inventory, Raw Materials and Supplies, Gross Cost of Purchased Power Cost of Goods and Services Sold Regulatory Assets [Domain] Regulatory Asset [Domain] Senior Unsecured Notes Due 2049 Senior Unsecured Notes Due 2049 [Member] Senior Unsecured Notes Due 2049 [Member] Integrated Generation Integrated Generation [Member] Integrated Generation Entity Central Index Key Entity Central Index Key Black Hills Energy - Nebraska Gas Black Hills Energy - Nebraska Gas [Member] Black Hills Energy - Nebraska Gas [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Percentage Of Monthly Redemption Percentage Of Monthly Redemption Percentage of shares that may be redeemed at the end of each month. Asset Retirement Obligation Costs [Line Items] Asset Retirement Obligation Costs [Line Items] Costs provided for the retirement of certain long-live assets that are reasonably expected to be recovered in utility rates charged to customers [Line Items] Regulatory liabilities Deferred Tax Assets, Regulatory Assets and Liabilities Market - off-system sales Market Off-System Sales [Member] Market Off-System Sales [Member] Black Hills Energy - Colorado Electric Black Hills Energy - Colorado Electric [Member] Black Hills Energy - Colorado Electric Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Reductions for prior year tax positions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Northern Natural Gas - Ventura NNG-Ventura [Member] NNG-Ventura [Member] Lessor, Lease, Description [Line Items] Lessor, Lease, Description [Line Items] Property, Plant and Equipment Property Plant Equipment Excluding Construction In Progress Property Plant Equipment excluding Construction in Progress Loss Contingencies [Line Items] Loss Contingencies [Line Items] Property, Plant and Equipment Property, Plant and Equipment Disclosure [Text Block] Other deferred credits and other liabilities Other Liabilities, Noncurrent Settlement Reached with the Regulatory Agency Settlement Reached with the Regulatory Agency [Member] Settlement Reached with the Regulatory Agency Projected benefit obligation at beginning of year Projected benefit obligation at end of year Defined Benefit Plan, Benefit Obligation Schedule of Long-term Debt Instruments Schedule of Long-term Debt Instruments [Table Text Block] Debt Instrument [Line Items] Debt Instrument [Line Items] Trading Symbol Trading Symbol Derivative Assets, Fair Value Disclosure Derivative Asset Related Party Transaction [Domain] Related Party Transaction [Domain] Other deferred tax liabilities Deferred Tax Liabilities, Other Line of Credit Facility, Current Borrowing Capacity Line of Credit Facility, Current Borrowing Capacity Amortization Of excess deferred income tax expense Effective Income Tax Reconciliation, Amortization Of Excess Deferred Income Tax Expense Effective Income Tax Reconciliation, Amortization Of Excess Deferred Income Tax Expense Retiree contributions Defined Benefit Plan, Plan Assets, Contributions by Plan Participant Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Long-term debt, net of current maturities Long-term debt, net of current maturities Long-term Debt, Excluding Current Maturities Schedule of Goodwill [Table] Schedule of Goodwill [Table] Unusual or Infrequent Item, or Both [Axis] Unusual or Infrequent Item, or Both [Axis] Research Tax Credit Carryforward Research Tax Credit Carryforward [Member] Long-term Purchase Commitment [Table] Long-term Purchase Commitment [Table] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Net income Net income Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Investments [Domain] Investments [Domain] We maintain natural gas supply contracts with several vendors that generally cover a period up to: Natural Gas Delivery Commitments And Contracts Term Natural Gas Delivery Commitments And Contracts Term Cash, restricted cash and cash equivalents beginning of year Cash, restricted cash and cash equivalents end of year Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Interest expense incurred net of amounts capitalized (including amortization of debt issuance costs, premiums and discounts) Interest expense incurred net of amounts capitalized (including amortization of debt issuance costs, premiums and discounts) [Member] Interest expense incurred net of amounts capitalized (including amortization of debt issuance costs, premiums and discounts) Sale of Stock, Number of Shares Issued in Transaction Sale of Stock, Number of Shares Issued in Transaction Common stock, par value (usd per share) Common Stock, Par or Stated Value Per Share Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Guarantor, Maximum Exposure Guarantor Obligations, Maximum Exposure, Undiscounted Current assets: Assets, Current [Abstract] Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Other financing activities Proceeds from (Payments for) Other Financing Activities Settlement Total of Plan to Provide TCJA and State Tax Reform benefits to Customers Settlement Total of Plan to Provide TCJA and State Tax Reform benefits to Customers Settlement Total of Plan to Provide TCJA and State Tax Reform benefits to Customers Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Commodity Option Commodity Option [Member] Internal Revenue Service (IRS) Internal Revenue Service (IRS) [Member] Performance Shares, Liability Awards Performance Shares, Liability Awards [Member] The liability components of equity Performance Shares awards [Member] Asset Retirement Obligation Disclosure [Abstract] Asset Retirement Obligation Disclosure [Abstract] Other comprehensive income (loss), net of tax Other comprehensive (loss), net of tax Other Comprehensive Income (Loss), Net of Tax Fair Value, Measurements, Recurring Fair Value, Recurring [Member] Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Accrued interest Interest Payable, Current Cost of removal Removal Costs [Member] Write-offs and Other Deductions Accounts Receivable, Allowance for Credit Loss, Writeoff Dividend Reinvestment Plan Dividend Reinvestment and Stock Purchase Plan [Member] Dividend Reinvestment and Stock Purchase Plan [Member] Measurement Basis [Axis] Measurement Basis [Axis] Future Amortization Expense, Year Five Finite-Lived Intangible Asset, Expected Amortization, Year Five Antidilutive Securities Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Fair Value Measurements Fair Value of Financial Instruments, Policy [Policy Text Block] Other income (expense): Nonoperating Income (Expense) [Abstract] Auditor Firm ID Auditor Firm ID Net cash (used in) investing activities Net Cash Provided by (Used in) Investing Activities Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Change in certain operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Target shares, value Employee Service Share-based Compensation, Other Than Options, Total Payout Value The amount of the total payout for an employee service share-based compensation award for other than options that has been accrued at the Balance Sheet date. The total value includes the stock price, dividends and the percentage payout value. Busch Ranch I Wind Farm Busch Ranch I Wind Farm [Member] Busch Ranch I Wind Farm [Member] Electric Generation Capacity, Megawatts Number of Megawatts Capacity Purchased - old Number of Megawatts being purchased under capacity and energy contract Public Utilities Amount of System Safety and Integrety Rider Moved to Base Rates Public Utilities Amount of System Safety and Integrety Rider Moved to Base Rates Public Utilities Amount of System Safety and Integrety Rider Moved to Base Rates Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification,Tax (Benefit) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax Sharing Arrangement with the City of Gillette, Wyoming Sharing Arrangement with the City of Gillette, Wyoming [Member] Sharing Arrangement with the City of Gillette, Wyoming [Member] Schedule of Accumulated and Projected Benefit Obligations Schedule of Accumulated and Projected Benefit Obligations [Table Text Block] Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity Segment Reporting Information [Line Items] Segment Reporting Information Segment Reporting Information [Line Items] Revenue Subject to Refund Revenue Subject to Refund [Member] Proportionate Ownership Share of other Party Jointly Owned Utility Plant, Proportionate Ownership Share of other Party Jointly Owned Utility Plant, Proportionate Ownership Share of other Party External Customers External Customers [Member] External Customers Taxes - property and production Taxes, Miscellaneous Transportation Transportation [Member] Transportation [Member] Discount Rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Transmission Service Agreement Transmission Service Agreement [Member] Other current assets Other Assets, Current Rate of increase in compensation levels Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Goodwill Deferred Tax Liabilities, Goodwill Dilutive effect of: Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Derivative Liability, Fair Value, Gross Liability Derivative Liability, Fair Value, Gross Liability Derivative Liability, Fair Value, Gross Liability Derivative, Remaining Maturity Derivative, Remaining Maturity Net (gain) loss Accumulated Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Tax Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] 2022-2023 Total Contract Capacity in Megawatts Due in Year Three of the Contract Total Contract Capacity in Megawatts Due in Year Three of the Contract Fuel, purchased power and cost of natural gas sold Cost of Sales [Member] Construction in progress, gross Construction in Progress, Gross 2023 Lessor, Operating Lease, Payment to be Received, Year Three Name of Property [Domain] Name of Property [Domain] (Tax) benefit on reclassification adjustment of benefit plan liability - net loss Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax Basis Swap Basis Swap [Member] Materials, Supplies and Fuel Inventory, Policy [Policy Text Block] State NOL (a) Deferred Tax Assets, Operating Loss Carryforwards, State and Local Thereafter Unrecorded Unconditional Purchase Obligation, to be Paid, after Year Five Pension Plan Pension Plan [Member] Megawatts Sold Under Long-Term Contract Number of Megawatts Sold Under Long-Term Contract Number of Megawatts Sold Under Long-Term Contract Regulated Operations [Abstract] Regulated Operations [Abstract] Less unamortized debt discount Debt Instrument, Unamortized Discount Netting Contract by Category [Axis] Netting Contract, Category [Axis] Netting Contract by Category [Axis] Capital Expenditures Property, Plant and Equipment, Gross, Period Increase (Decrease) Deferred Tax Asset [Domain] Deferred Tax Asset [Domain] Jointly Owned Utility Plant Interests [Line Items] Jointly Owned Utility Plant Interests [Line Items] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Black Hills Energy - South Dakota Electric South Dakota Electric South Dakota Electric [Member] South Dakota Electric ONEOK - Oklahoma ONEOK - Oklahoma [Member] ONEOK - Oklahoma