Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Credit rating2 Credit Rating [Member] Credit Rating [Member] Trading Arrangement: Trading Arrangement [Axis] High Maximum [Member] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Statistical Measurement [Domain] Statistical Measurement [Domain] Assets: Offsetting Derivative Assets [Abstract] Derivative [Table] Offsetting Assets and Liabilities [Table] Offsetting Assets and Liabilities [Table] Less: Accumulated depreciation and amortization Public Utilities, Property, Plant and Equipment, Accumulated Depreciation Carrying Value Reported Value Measurement [Member] Document Fiscal Year Focus Document Fiscal Year Focus Unique Name [Axis] Unique Name [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Gross Amounts Offset in the Statement of Financial Position Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Offset Adjustment to Compensation, Amount Adjustment to Compensation Amount Purchase Power Contract 1 Purchase Power Contract 1 [Member] Purchase Power Contract 1 Long-Term Contract for Purchase of Electric Power [Axis] Long-Term Contract for Purchase of Electric Power [Axis] Customer [Axis] Customer [Axis] Segment Reporting [Abstract] Compliance Obligation, Current Compliance Obligation, Current Compliance Obligation, Current Energy Hedging Activities Energy Hedging Activities [Member] Energy Hedging Activities Common stock $0.01 par value, 1,000 shares authorized, 200 shares outstanding Common Stock, Value, Issued Salaries and wages Employee-related Liabilities, Current Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Pension and Other Postretirement Benefits Disclosure [Text Block] Retirement Benefits [Text Block] Power contract acquisition adjustment loss Power Contract Acquisition Adjustment Loss Non Current Long term fair value adjustment of the power contract acquisitions that will be recognized as income after one year. Leases Lessee, Finance Leases [Text Block] Restatement Determination Date Restatement Determination Date Gross Amounts Offset in the Statement of Financial Position Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash, Offset Against Derivative Asset Total other property and investments Total Other Property And Investments Total other property and investments. Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Derivative Instrument [Axis] Derivative, by Nature [Axis] Derivative Instrument [Axis] Beginning balance Total ending allowance balance Accounts Receivable, Allowance for Credit Loss Junior Subordinated Debt Junior Subordinated Debt [Member] Amendment Flag Amendment Flag Current liabilities: Liabilities, Current [Abstract] Consolidated Entities [Axis] Consolidated Entities [Axis] Provision for credit loss expense1 Accounts Receivable, Credit Loss Expense (Reversal) Project [Axis] Project [Axis] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Standby Letters of Credit Standby Letters of Credit [Member] Loss Contingencies [Table] Loss Contingencies [Table] Leases [Abstract] Leases [Abstract] Consolidated Entities [Domain] Consolidated Entities [Domain] Fair Value Measurements, Sensitivity Analysis, Hypothetical Increase or Decrease of Market Prices, Result on Fair Value Fair Value Measurements, Sensitivity Analysis, Hypothetical Increase or Decrease of Market Prices, Result on Fair Value Fair Value Measurements, Sensitivity Analysis, Hypothetical Increase or Decrease of Market Prices, Result on Fair Value Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Under Under-collection [Member] Under-collection Entity Address, State or Province Entity Address, State or Province Regulatory liabilities related to power contracts Regulatory Liabilities Related To Power Contracts Liabilities incurred for regulatory matters related to power contracts. PEO Total Compensation Amount PEO Total Compensation Amount Battery Energy Storage System Battery Energy Storage System [Member] Battery Energy Storage System Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Asset Acquisition [Axis] Asset Acquisition [Axis] Consolidation, Elimination, Obligor Group and Nonobligor Subsidiary Consolidation, Elimination, Obligor Group and Nonobligor Subsidiary [Member] Retirement Benefits [Abstract] Retirement Benefits [Abstract] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Total capitalization Capitalization, Long-Term Debt and Equity Residential Residential [Member] Residential Loss Contingencies [Line Items] Loss Contingencies [Line Items] Number of Reportable Segments Number of Reportable Segments Total current liabilities Liabilities, Current Long-term debt (fixed-rate), net of discount Long-term Debt, Fixed Rate, Net of Discount, Fair Value Disclosure Long-term Debt, Fixed Rate, Net of Discount, Fair Value Disclosure Other property and investments Other Property And Investments Other property and investments Construction expenditures - excluding equity AFUDC Construction expenditures Construction expenditures excluding equity allowance for funds used during construction The cash outflow for acquisition of or capital improvements to properties held for investment (operating, managed, leased) or for use, excluding equity AFUDC. Other Unregulated Operating Revenue Natural gas Regulated Operating Revenue, Gas Annual Power Cost Variability Annual Power Cost Variability Annual Power Cost Variability Unrealized loss on derivative instruments Current, Liabilities Derivative Liability, Current Total revenue from contracts with customers Revenue from Contract with Customer, Including Assessed Tax Other long-term assets and liabilities Increase (Decrease) in Other Noncurrent Assets and Liabilities, Net Forward value of contract3 Forward Value of Contract [Member] Forward Value of Contract [Member] Entity Address, City or Town Entity Address, City or Town Asset Acquisition, Consideration Transferred Asset Acquisition, Consideration Transferred Variable Interest Entity, Measure of Activity, Expense Variable Interest Entity, Measure of Activity, Expense Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Commercial Paper Commercial Paper Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Power cost adjustment mechanism Power Cost Adjustment Mechanism Asset, Noncurrent Regulatory asset that provides for recovery of power costs from customers. Excess power costs or power cost savings will be apportioned between PSE and its customers. Document Information [Line Items] Document Information [Line Items] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Schedule of PGA Receivable Payable Schedule of PGA Receivable Payable [Table Text Block] Schedule of PGA Receivable Payable Residential exchange Utilities Operating Expense, Residential Exchange Costs Changes in the current period carrying value of the residential exchange program. Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Derivative, Nonmonetary Notional Amount Derivative, Nonmonetary Notional Amount Hedging strategy number of years extended Hedging strategy number of years extended Hedging strategy number of years extended Natural gas plant Public Utilities Property Plant And Equipment Gas Plant The period end book value of the gas plant. Annual Power Cost Variability, Interest Annual Power Cost Variability, Interest Annual Power Cost Variability, Interest Electric plant Public Utilities Property Plant And Equipment Electric Plant The period end book value of the electric plant. Level 2 Fair Value, Inputs, Level 2 [Member] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Parent Company Parent Company [Member] Name of Property [Axis] Name of Property [Axis] Variable Interest Entity, Payable Variable Interest Entity, Payable Variable Interest Entity, Payable Amortization of treasury interest rate swaps to earnings, net of tax Amortization Of Financing Cash Flow Hedge Contracts To Earnings During Period Net Of Tax Net of tax effect, amortization for accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges included in accumulated comprehensive income that was realized in net income during the period. Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Commodity Contracts Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Security Not Offset Transmission and transportation Transmission and Transportation [Member] Transmission and Transportation Compliance obligation Compliance Obligation, Non -Current Compliance Obligation, Non -Current Accounts payable for capital expenditures eliminated from cash flows Capital Expenditures Incurred but Not yet Paid Segment Reporting Segment Reporting [Table Text Block] Other Other Retail Customer [Member] Other Retail Customer Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax Electric Regulated Operating Revenue, Electric, Non-Nuclear Notes Receivable, Fair Value Disclosure Notes Receivable, Fair Value Disclosure External Credit Rating by Grouping [Domain] External Credit Rating by Grouping [Domain] Other, Utility Plant Property, Plant, and Equipment [Text Block] Non-cash financing and investing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Taxes payable Increase (Decrease) in Income Taxes Payable Document Period End Date Document Period End Date Change in certain current assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Climate Commitment Act Climate Commitment Act [Member] Climate Commitment Act Net cash provided by (used in) investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] 7.250% Junior Subordinated Notes Series B Due 2056 7.250% Junior Subordinated Notes Series B Due 2056 [Member] 7.250% Junior Subordinated Notes Series B Due 2056 Subsidiaries Subsidiaries [Member] Cash Collateral Received Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash Not Offset Other property and investments: Other Property And Investments [Abstract] Debt Instrument, Face Amount Debt Instrument, Face Amount AFUDC - equity AFUDC Equity The increase (decrease) during the reporting period in AFUDC-Equity. Equity component of allowance for funds used during construction. Regulatory liabilities Regulatory Liabilities, Noncurrent Regulatory Liabilities, Noncurrent Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Total liabilities Liabilities, Fair Value Disclosure Accumulated other comprehensive income (loss), net of tax Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company GHG emission allowances GHG Emission Allowances, Current GHG Emission Allowances, Current Purchase Power Contract 3 Purchase Power Contract 3 [Member] Purchase Power Contract 3 Operating lease liabilities Operating Lease, Liability, Current Accounts Receivable, Allowance for Credit Loss Accounts Receivable, Allowance for Credit Loss [Table Text Block] Interest Interest Payable, Current Total finance lease assets Finance Lease, Right-of-Use Asset, after Accumulated Amortization Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Other deferred credits Other Deferred Credits Other deferred credits Name Outstanding Recovery, Individual Name Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Document Fiscal Period Focus Document Fiscal Period Focus Commodity Contracts Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Security Not Offset Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Purchased electricity Utilities Operating Expense, Purchased Power Public Utilities, Approved Rate Increase (Decrease), Amount Public Utilities, Approved Rate Increase (Decrease), Amount Summary of Consolidation Policy Schedule of Capitalization, Equity [Line Items] Company Selected Measure Name Company Selected Measure Name Business Combination, Contingent Consideration, Type [Axis] Business Combination, Contingent Consideration, Type [Axis] Schedule of Regulatory Assets [Table] Regulated Operation, Regulatory Asset [Table] Ownership percentage Subsidiary, Ownership Percentage, Parent Credit Facility [Domain] Credit Facility [Domain] Operating activities: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Compensation Amount Outstanding Recovery Compensation Amount Colstrip Units 1 and 2 Colstrip Units 1 and 2 [Member] Colstrip Units 1 and 2 [Member] Individual: Individual [Axis] Public Utility [Axis] Public Utility [Axis] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Entity Emerging Growth Company Entity Emerging Growth Company Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Deferred income taxes and tax credits, net Deferred Income Taxes and Tax Credits Accounting for Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities Disclosure [Text Block] Short-term debt Short-Term Debt Gross Amount Recognized in the Statement of Financial Position Derivative Liability, Subject to Master Netting Arrangement, before Offset Line of Credit Facility, Current Borrowing Capacity Line of Credit Facility, Current Borrowing Capacity Employer contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Financial Support to Nonconsolidated Legal Entity [Axis] Financial Support to Nonconsolidated Legal Entity [Axis] Natural Gas Processing Plant Natural Gas Processing Plant [Member] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Schedule of Regulatory Assets and Liabiliaties [Line Items] Schedule of Regulatory Assets and Liabiliaties [Line Items] Schedule of Regulatory Assets and Liabiliaties [Line Items] Energy costs: Energy Costs [Abstract] Award Timing Predetermined Award Timing Predetermined [Flag] Capitalization: Capitalization [Abstract] Capitalization [Abstract] Project [Domain] Project [Domain] Net utility plant Public Utilities, Property, Plant and Equipment, Net Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Other expense Other Nonoperating Expense Unrealized gain on derivative instruments Long-term, Assets Derivative Asset, Noncurrent Value no cost allowances passed back to customers that exceeded usage, Regulatory Asset Value no cost allowances passed back to customers that exceeded usage, Regulatory Asset Value no cost allowances passed back to customers that exceeded usage, Regulatory Asset Power contract acquisition adjustment gain Power Contract Acquisition Adjustment Gain Current Current Fair Value adjustment of the power contract acquisitions, that will be recognized as income within one year. Lessor, Lease, Description [Table] Lessor, Lease, Description [Table] Purchased gas adjustment receivable purchase gas adjustment, long-term purchase gas adjustment, long-term All Executive Categories All Executive Categories [Member] Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Regulated Operations [Abstract] Discounted cash flow Valuation, Income Approach [Member] Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Schedule of Net Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Asset Acquisition [Domain] Asset Acquisition [Domain] Scenario [Domain] Scenario [Domain] Deferred income taxes Deferred Tax and Other Liabilities, Noncurrent Regulatory assets related to power contracts Regulatory Assets Related To Power Contracts Regulatory assets recorded in relation to power contracts Operating lease right-of-use asset Total operating lease right-of-use assets Operating Lease, Right-of-Use Asset First mortgage bonds and senior notes Senior Notes, Noncurrent Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Public Utilities, Approved Rate Increase (Decrease), Percentage Public Utilities, Approved Rate Increase (Decrease), Percentage Debt Disclosure [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Customer's share plus interest Customer's share plus interest [Member] Customer's share plus interest Segment Information Segment Reporting [Text Block] Low Minimum [Member] Expiration Date Trading Arrangement Expiration Date Tacoma LNG Tacoma LNG [Member] Tacoma LNG [Member] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Commercial Commercial [Member] Commercial Total other long-term and regulatory assets Total Longterm And Regulatory Assets Total of all long term and regulatory assets. Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Public Utilities, Regulatory Proceeding [Domain] Public Utilities, Regulatory Proceeding [Domain] Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Beaver Creek Wind Project Beaver Creek Wind Project [Member] Beaver Creek Wind Project Schedule of Graduated Scale of Rate Adjustment Mechanism Schedule of Graduated Scale of Rate Adjustment Mechanism [Table Text Block] Schedule of Graduated Scale of Rate Adjustment Mechanism Common stock dividend paid Dividends, Common Stock Net periodic benefit cost Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Unamortized investment tax credits Accumulated Deferred Investment Tax Credit Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Derivative [Table] Derivative [Table] Common stock, shares authorized (in shares) Common Stock, Shares Authorized Agreement Term Agreement Term Agreement Term Accounts receivable and unbilled revenue Increase (Decrease) in Accounts and Other Receivables Schedule of Regulatory Assets and Liabiliaties [Table] Schedule of Regulatory Assets and Liabiliaties [Table] Schedule of Regulatory Assets and Liabiliaties [Table] Exercise Price Award Exercise Price Investing activities: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Segment Reporting [Line Items] Segment Reporting [Line Items] Document Quarterly Report Document Quarterly Report Purchased gas adjustment increase (decrease) in purchased gas increase (decrease) in purchased gas Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Segments [Domain] Segments [Domain] Grays Harbor Tolling Grays Harbor Tolling [Member] Grays Harbor Tolling [Member] Electric Plant Electric Plant [Member] Electric Plant [Member] Other, Long Term Debt Debt Disclosure [Text Block] Deferred Emission Compliance Auction Proceeds, Regulatory Liability Deferred Emission Compliance Auction Proceeds, Regulatory Liability Deferred Emission Compliance Auction Proceeds, Regulatory Liability Redemption of bonds and notes Repayments of Long-Term Debt Scenario [Axis] Scenario [Axis] Operating Activities [Domain] Operating Activities [Domain] Contractual Obligation Contractual Obligation Deferred Emission Compliance Costs, Regulatory Liability Deferred Emission Compliance Costs, Regulatory Liability Deferred Emission Compliance Costs, Regulatory Liability Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Equity Component [Domain] Equity Component [Domain] Common plant Public Utilities Property Plant And Equipment Common Plant The period end book value of the common plant. PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Adoption Date Trading Arrangement Adoption Date Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Counterparty Name [Domain] Counterparty Name [Domain] Total common shareholder’s equity Beginning Balance Ending Balance Equity, Attributable to Parent Investment Tax Credit Investment Tax Credit ASSETS Assets [Abstract] Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Included in regulatory assets / liabilities Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Regulatory Assets (Liabilities) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Regulatory Assets (Liabilities) Accounting Policies [Abstract] Accounting Policies [Abstract] Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Public Utilities, Requested Return on Equity, Percentage Public Utilities, Requested Return on Equity, Percentage Derivative [Line Items] Offsetting Assets and Liabilities [Line Items] [Line Items] for Offsetting Assets and Liabilities [Table] Operating Lease, Liability Operating Lease, Liability Operating Lease, Liability Insider Trading Policies and Procedures [Line Items] Total finance lease liabilities Finance Lease, Liability Other Proceeds from (Payment for) Other Financing Activity Allowance for doubtful accounts Accounts Receivable, Allowance for Credit Loss, Current Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Purchased natural gas adjustment, interest Purchased natural gas adjustment, interest Purchased natural gas adjustment, interest Utility Plant [Abstract] Utility Plant [Abstract] Prepaid expense and other Prepaid Expense and Other Assets, Current Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Variable Interest Entity, Measure of Activity, capacity Variable Interest Entity, Measure of Activity, Contracted Capacity Variable Interest Entity, Measure of Activity, Contracted Capacity Commitments and Contingencies Disclosure Commitments and Contingencies Disclosure [Text Block] Purchased gas adjustment liability Purchased Gas Adjustment Liability, Long-term Purchased Gas Adjustment Liability, Long-term Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Construction in Progress, Gross Construction in Progress, Gross Number of Operating Segments Number of Operating Segments Entity Central Index Key Entity Central Index Key Weighted Average Weighted Average [Member] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] All Adjustments to Compensation All Adjustments to Compensation [Member] Name of Property [Domain] Name of Property [Domain] Customers' Share Customer's share [Member] Customer's share Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Net cash provided by (used in) operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Long-Term Contract for Purchase of Electric Power [Domain] Long-Term Contract for Purchase of Electric Power [Domain] Requested credit for adequate assurance Requested Credit for Adequate Assurance [Member] Requested Credit for Adequate Assurance [Member] Common shareholder’s equity: Equity, Attributable to Parent [Abstract] Income Statement [Abstract] Income Statement [Abstract] Deferred Emission Compliance Auction Proceeds, Passback to Customers Deferred Emission Compliance Auction Proceeds, Passback to Customers Deferred Emission Compliance Auction Proceeds, Passback to Customers Document Transition Report Document Transition Report Ownership [Axis] Ownership [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Investment, Name [Axis] Investment, Name [Axis] Operating expenses: Operating Expenses [Abstract] Finance lease liabilities Finance Lease, Liability, Noncurrent Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Reportable Segment, Aggregation before Other Operating Segment Reportable Segment, Aggregation before Other Operating Segment [Member] Number of Agreements Number of Agreements Number of Agreements Purchased Electricity Purchased Electricity [Member] Purchased Electricity [Member] Electric derivative instruments Electric Portfolio [Member] Electric Portfolio [Member] Debt Instrument, Basis Spread on Variable Rate Debt Instrument, Basis Spread on Variable Rate Lessor, Lease, Description [Line Items] Lessor, Lease, Description [Line Items] City Area Code City Area Code Colstrip Adjustment Rider Colstrip Adjustment Rider [Member] Colstrip Adjustment Rider Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] 7.000% Junior Subordinated Notes Due 2056 7.000% Junior Subordinated Notes Series A Due 2056 [Member] 7.000% Junior Subordinated Notes Series A Due 2056 Offsetting Assets and Liabilities Offsetting Assets and Liabilities [Table Text Block] Offsetting Assets and Liabilities [Table Text Block] Document Information [Table] Document Information [Table] All Individuals All Individuals [Member] Other Other [Member] Other Total other revenue2 Total Other Revenue Total Other Revenue Dividends paid Payments of Dividends Name Forgone Recovery, Individual Name Interest charges: Interest Costs Incurred [Abstract] Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Other regulatory assets Other Regulatory Assets Carrying amount as of the balance sheet date of other capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer. Total long-term and regulatory liabilities Total Longterm And Regulatory Liabilities Total of all long term and regulatory liabilities. Statement [Line Items] Statement [Line Items] Total assets Total assets Assets Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan [Table] Regulatory liability for deferred income taxes Deferred Tax Liabilities, Regulatory Assets and Liabilities New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Accounting Standards Update and Change in Accounting Principle [Abstract] Amortization of prior service cost Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] PEO PEO [Member] Line of Credit Facility, Maximum Amount Outstanding During Period Line of Credit Facility, Maximum Amount Outstanding During Period Area of Service Territory (in sqmi) Area of Service Territory Area of Service Territory Amortization of Financing Cash Flow Hedge Contracts to Earnings Tax Amortization of Financing Cash Flow Hedge Contracts to Earnings Tax Amortization of Financing Cash Flow Hedge Contracts to Earnings Tax Measurement Basis [Axis] Measurement Basis [Axis] Goodwill Goodwill Retirement Plan Type [Axis] Retirement Plan Type [Axis] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Purchased Gas Adjustment, Schedule 101 Purchased Gas Adjustment, Schedule 101 [Member] Purchased Gas Adjustment, Schedule 101 Nameplate Capacity Nameplate Capacity Nameplate Capacity Retained Earnings Retained Earnings [Member] Operating lease liabilities Operating Lease, Liability, Noncurrent Taxes Taxes Payable, Current Total operating expenses Operating Expenses Long-term debt Other Long-Term Debt, Noncurrent AFUDC Public Utilities, Allowance for Funds Used During Construction, Additions Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Fair Value Inputs, Liabilities, Quantitative Information Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common Stock, Shares, Outstanding Beginning Balance (in shares) Ending Balance (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Deferred Interest Term Deferred Interest Term Deferred Interest Term Entity Current Reporting Status Entity Current Reporting Status Net cash provided by (used in) financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount HQC Solar Holdings 1, LLC HQC Solar Holdings 1, LLC [Member] HQC Solar Holdings 1, LLC Prepayments and other Increase (Decrease) in Prepaid Expense and Other Assets Liabilities: Liabilities, Fair Value Disclosure [Abstract] Annual Power Cost Variability, by Recovery Type [Axis] Annual Power Cost Variability, by Recovery Type [Axis] Annual Power Cost Variability, by Recovery Type [Axis] Ownership [Domain] Ownership [Domain] Purchased natural gas costs, recoverable Purchased natural gas costs, recoverable Purchased natural gas costs, recoverable Adjustments to reconcile net income (loss) to net cash provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Receivables charged-off Accounts Receivable, Allowance for Credit Loss, Writeoff Natural Gas Natural Gas [Member] Financing activities: Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Additional Collateral, Aggregate Fair Value Additional Collateral, Aggregate Fair Value Regulatory Assets [Line Items] Regulatory Asset [Line Items] Interest cost Defined Benefit Plan, Interest Cost Other Regulated Operating Revenue, Other Natural gas derivatives (MMBtus)3 Natural Gas Derivatives [Member] Natural Gas Derivatives [Member] Assets Derivative Assets Derivative Asset Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Underlying Securities Award Underlying Securities Amount Fair Value Estimate of Fair Value Measurement [Member] Revenue Revenue from Contract with Customer [Text Block] Appaloosa Solar Project Appaloosa Solar Project [Member] Appaloosa Solar Project Net Amount Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Battle Butte Solar Project Battle Butte Solar Project [Member] Battle Butte Solar Project Other Payment for (Proceeds from) Other Investing Activity Segment Reporting [Table] Segment Reporting [Table] Aggregate expected contributions Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year Other long-term and regulatory liabilities: Longterm And Regulatory Liabilities [Abstract] Public Utilities, Approved Debt Capital Structure, Percentage Public Utilities, Approved Debt Capital Structure, Percentage Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Other income (expense): Other Nonoperating Income (Expense) [Abstract] All Trading Arrangements All Trading Arrangements [Member] Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Operating income (loss) Operating Income (Loss) Electricity, US Regulated [Member] Electricity, US Regulated [Member] Other Noncurrent Liabilities Other, Noncurrent [Member] Other, Noncurrent Remaining performance obligations Revenue, Remaining Performance Obligation, Amount Fuel and natural gas inventory, at average cost Fuel And Gas Inventory At Average Cost The carrying amount of the fuel and gas inventory used in the generation of electricity and for future sales to the Company's natural gas customers, calculated using the average cost method, as of the balance sheet date. Current Fiscal Year End Date Current Fiscal Year End Date Beaver Creek 2 Wind Project Beaver Creek 2 Wind Project [Member] Beaver Creek 2 Wind Project PCA Mechanism PCA Mechanism [Member] PCA Mechanism [Member] Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Derivative [Line Items] Derivative [Line Items] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Service cost Defined Benefit Plan, Service Cost Change in short-term debt, net Proceeds from (Repayments of) Short-Term Debt Regulation and Rates [Table] Regulation and Rates [Table] Regulation and Rates [Table] Remaining Contract Term, PLNG Remaining Contract Term, PLNG Remaining Contract Term, PLNG Company's Share Companys share [Member] Companys share Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Proceeds From Sale of Transferable Tax Credits Proceeds From Sale of Transferable Tax Credits Proceeds From Sale of Transferable Tax Credits Measure: Measure [Axis] Purchase Power Contract Purchase Power Contract [Member] Purchase Power Contract Equity Components [Axis] Equity Components [Axis] Product and Service [Domain] Product and Service [Domain] Public Utilities, Allowance for Funds Used During Construction, Rate Public Utilities, Allowance for Funds Used During Construction, Rate Regulatory assets and liabilities Increase (Decrease) in Regulatory Assets and Liabilities Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] CAPITALIZATION AND LIABILITIES Capitalization, Long-Term Debt and Equity [Abstract] Entity Interactive Data Current Entity Interactive Data Current Finance Lease, Liability, Current Finance Lease, Liability, Current Lease, Remaining Lease Term Lease, Remaining Lease Term Lease, Remaining Lease Term Funding Participant Contract Funding Participant Contract [Member] Funding Participant Contract Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Investment from Parent Proceeds from Contributions from Parent Entity Small Business Entity Small Business Natural gas derivative instruments Natural Gas Portfolio [Member] Natural Gas Portfolio [Member] Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Natural Gas, US Regulated [Member] Natural Gas, US Regulated [Member] Termination Date Trading Arrangement Termination Date Working Capital Needs [Member] Working Capital Needs [Member] Working Capital Needs [Member] Utility Plant [Domain] Utility Plant [Domain] Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Net unrealized gain (loss) from pension and postretirement plans, net of tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Net Amount Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Other Other Liabilities, Current Other Other Assets, Noncurrent Document Type Document Type Other [Abstract] Other [Abstract] Other [Abstract] Materials and supplies, at average cost Materials, Supplies, and Other Conservation amortization Utilities Operating Expense, Conservation Amortization The amount of expense recognized in the current period that reflects the allocation of conservation expenditures over the prescribed amortization period. 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] Unrealized gain on derivative instruments Current, Assets Derivative Asset, Current Annual Power Cost Variability, by Party [Domain] Annual Power Cost Variability, by Party [Domain] Annual Power Cost Variability, by Party [Domain] Fair Value as of Grant Date Award Grant Date Fair Value Operating Activities [Axis] Operating Activities [Axis] Significant Accounting Policies Significant Accounting Policies [Text Block] Common Plant Common Plant [Member] Common Plant [Member] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Operating Costs and Expenses Operating Costs and Expenses Arrangement Duration Trading Arrangement Duration Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Proceeds from long-term debt and bonds issued Proceeds from Issuance of Long-Term Debt Local Phone Number Local Phone Number Entity Registrant Name Entity Registrant Name Entity Address, Postal Zip Code Entity Address, Postal Zip Code Annual Power Cost Variability, Range [Domain] Annual Power Cost Variability, Range [Domain] [Domain] for Annual Power Cost Variability, Range [Axis] Public Utilities, Approved Equity Capital Structure, Percentage Public Utilities, Approved Equity Capital Structure, Percentage Income (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Commitments and contingencies (Note 8) Commitments and Contingencies Revenues Revenues Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Derivative, Credit Risk Exposure, Percentage Derivative, Credit Risk Exposure, Percentage Derivative, Credit Risk Exposure, Percentage Counterparty Name [Axis] Counterparty Name [Axis] Assets and Liabilities, Lessee Assets and Liabilities, Lessee [Table Text Block] Assets and Liabilities, Lessee 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] All Award Types Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Fair Value Liability Derivative, Net Liability Position, Aggregate Fair Value Fair Value Measurements Fair Value Disclosures [Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] Variable Interest Entity [Table] Variable Interest Entity [Table] Materials and supplies Increase (Decrease) in Materials and Supplies Jointly Owned Non-Utility Plant Share Jointly Owned Non-Utility Plant Share Jointly Owned Non-Utility Plant Share Supplemental cash flow information: Supplemental Cash Flow Information [Abstract] External Credit Rating, Non Investment Grade External Credit Rating, Noninvestment Grade [Member] Purchased natural gas Utilities Operating Expense, Gas and Petroleum Purchased Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Industrial Industrial [Member] Industrial PEO Name PEO Name Puget LNG Puget LNG [Member] Puget LNG [Member] Restricted Cash Restricted Cash Electric Generation Fuel Electric Generation Fuel [Member] Electric Generation Fuel [Member] Purchased allowances net obligation costs collected in rates, Regulatory Asset Purchased allowances net obligation costs collected in rates, Regulatory Asset Purchased allowances net obligation costs collected in rates, Regulatory Asset Cash payments (refunds) for income taxes Income Tax Paid, before Refund Received Purchase Power Contract 2 Purchase Power Contract 2 [Member] Purchase Power Contract 2 Over Over-collection [Member] Over-collection Price (per MWh) Fair Value Inputs, Price Per Megawatt-Hour Fair Value Inputs, Price Per Megawatt-Hour Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Accounts Receivable, Allowance for Credit Loss [Roll Forward] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Ratio of Indebtedness to Net Capital Ratio of Indebtedness to Net Capital Interest expense Interest expense Interest Expense, Debt Liability Class [Axis] Liability Class [Axis] Miscellaneous1 Miscellaneous Customer [Member] Miscellaneous Customer Cash, cash equivalents, and restricted cash at beginning of period Cash, cash equivalents, and restricted cash at end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Cash Collateral Posted Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Not Offset Accounts payable Increase (Decrease) in Accounts Payable Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] External Credit Rating, Investment Grade External Credit Rating, Investment Grade [Member] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Restricted cash Restricted Cash and Cash Equivalent, Current Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Colstrip Units 3 and 4 Colstrip Units 3 and 4 [Member] Colstrip Units 3 and 4 [Member] Debt Instrument [Axis] Debt Instrument [Axis] Ownership interest (percent) Equity Method Investment, Ownership Percentage Taxes other than income taxes Utilities Operating Expense, Taxes Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Axis] Investment, Name [Domain] Investment, Name [Domain] Customer [Domain] Customer [Domain] Leases Lessee, Operating Leases [Text Block] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] 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] Fair Value Inputs, Assets and Liabilities, Quantitative Information Fair Value Inputs, Assets and Liabilities, Quantitative Information [Table Text Block] Fair Value Inputs, Assets and Liabilities, Quantitative Information [Table Text Block] GHG emission allowances Increase (decrease) in greenhouse gas emissions allowances Increase (decrease) in greenhouse gas emissions allowances Total current assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] Insider Trading Arrangements [Line Items] Purchased natural gas costs Purchased natural gas costs Purchased natural gas costs Total long-term debt Long-Term Debt, Excluding Current Maturities General Rate Case General Rate Case [Member] General Rate Case [Member] Award Type Award Type [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Accounts receivable, net of allowance for doubtful accounts of $26,675 and $26,452, respectively Accounts Receivable, after Allowance for Credit Loss, Current Retained earnings Retained Earnings (Accumulated Deficit) Commodity Contract Commodity Contract [Member] Product and Service [Axis] Product and Service [Axis] (Over) and under collected between $17 - $40 million Range 2 [Member] Range 2 Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Schedule of Credit Risk Related Contingent Features Schedule of Credit Risk Related Contingent Features [Table Text Block] Schedule of Credit Risk Related Contingent Features [Table Text Block] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Qualified Pension Benefits Pension Plan [Member] Common Stock Common Stock [Member] Fair Value Measurement [Domain] Fair Value Measurement [Domain] External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Axis] Electric generation fuel Utilities Operating Expense, Fuel Used Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Purchased Gas Adjustment Purchased Gas Adjustment [Member] Purchased Gas Adjustment Bad Debt Deferral, COVID 19 Bad Debt Deferral, COVID 19 Bad Debt Deferral, COVID 19 Derivative Contract [Domain] Derivative Contract [Domain] Equity Awards Adjustments Equity Awards Adjustments [Member] Unbilled revenue Unbilled Revenues Operating utility revenues, recorded on the basis of services rendered, which have not been billed as of the balance sheet date. Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Total capitalization and liabilities Liabilities and Equity Unrealized loss on derivative instruments Long-term, Liabilities Derivative Liability, Noncurrent Employee Stock Option Share-Based Payment Arrangement, Option [Member] Electricity Electricity [Member] Summary of Consolidation Policy Capitalization, Equity [Table] Construction work in progress Public Utilities, Property, Plant and Equipment, Construction Work in Progress Public Utilities, Property, Plant and Equipment, Construction Work in Progress Segments [Axis] Segments [Axis] SERP Pension Benefits Supplemental Employee Retirement Plan [Member] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Jointly Owned Utility Plant [Axis] Jointly Owned Utility Plant [Axis] Tabular List, Table Tabular List [Table Text Block] Noncash or Part Noncash Divestiture, Name [Domain] Noncash or Part Noncash Divestiture, Name [Domain] Additional paid-in capital Additional Paid in Capital Other Current Liabilities Other, Current [Member] Other, Current ICE Margin ICE Margin [Member] ICE Margin Name Awards Close in Time to MNPI Disclosures, Individual Name Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Utility operations and maintenance Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Annual Power Cost Variability, Amount Annual Power Cost Variability, Amount Annual Power Cost Variability, Amount Business Combination, Contingent Consideration, Type [Domain] Business Combination, Contingent Consideration, Type [Domain] Other Revenue From Contracts with Customers [Member] Other Revenue From Contracts with Customers [Member] Other Revenue From Contracts with Customers [Member] - for use in 606 quantitative disclosure Jointly Owned Utility Plant [Domain] Jointly Owned Utility Plant [Domain] (Over) and under collected up to $17 million Range 1 [Member] Range 1 Adjustment to Compensation: Adjustment to Compensation [Axis] purchased gas adjustment, Schedule 106 106B Purchased Gas Adjustment, Schedule 106 & 106B [Member] Purchased Gas Adjustment, Schedule 106 & 106B Other Increase (Decrease) in Other Accounts Payable and Accrued Liabilities Annual Power Cost Variability, by Party [Axis] Annual Power Cost Variability, by Party [Axis] Annual Power Cost Variability, by Party [Axis] Annual Power Cost Variability, by Recovery Type [Domain] Annual Power Cost Variability, by Recovery Type [Domain] Annual Power Cost Variability, by Recovery Type [Domain] Hedging Designation [Domain] Hedging Designation [Domain] Power contract acquisition adjustment loss Power Contract Acquisition Adjustment Loss Current Current fair value adjustment of the power contract acquisitions that will be recognized as income within one year. Non-utility expense and other Nonutility Expense And Other The amount of unregulated operating and other expenses recognized during the period. Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Cash payments for interest (net of capitalized interest) Interest Paid, Excluding Capitalized Interest, Operating Activity Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Hedging Designation [Axis] Hedging Designation [Axis] Fuel and natural gas inventory Increase (Decrease) in Fuel Inventories Credit Facility [Axis] Credit Facility [Axis] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Total assets Assets, Fair Value Disclosure Other Benefits Other Pension Plan [Member] Number of Windmills Number of Windmills Number of Windmills Solar PV Energy Project Solar PV Energy Project [Member] Solar PV Energy Project Name Measure Name Accounts payable Accounts Payable, Current Pay vs Performance Disclosure [Line Items] Other Operating Segment Other Operating Segment [Member] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Other non-cash Other Noncash Income (Expense) Debt Instrument [Line Items] Debt Instrument [Line Items] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Additional Paid-in Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Asset Acquisition, Price of Acquisition, Expected Asset Acquisition, Price of Acquisition, Expected Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and Cash Equivalent Public Utilities, Requested Rate Increase (Decrease), Percentage Public Utilities, Requested Rate Increase (Decrease), Percentage Fair Value Inputs, Price Per Millions of BTU Fair Value Inputs, Price Per Millions of BTU Fair Value Inputs, Price Per Millions of BTU Company Selected Measure Amount Company Selected Measure Amount Not Designated as Hedging Instrument Not Designated as Hedging Instrument [Member] Regulation and Rates Disclosure Regulation and Rates Disclosure [Text Block] The entire disclosure of the events that have or may impact rates including, but not limited to, pending or recently concluded regulatory proceedings. Depreciation and amortization Depreciation, Depletion and Amortization Annual Power Cost Variability, Range [Axis] Annual Power Cost Variability, Range [Axis] Annual Power Cost Variability, Range [Axis] Long-term debt: Long-Term Debt, Excluding Current Maturities [Abstract] Debt discount issuance costs and other Debt discount and other Debt instrument unamortized discount and fair value adjustment of debt instrument, net. Current assets: Assets, Current [Abstract] Accrued expenses: Accrued Expenses [Abstract] Derivative Liability Derivative Liability Derivative Liability Non-PEO NEO Non-PEO NEO [Member] Entity Address, Address Line One Entity Address, Address Line One Other long-term and regulatory assets: Other Longterm And Regulatory Assets [Abstract] Income tax (benefit) expense Income Tax Expense (Benefit) Pollution control bonds Long-Term Pollution Control Bond Other income Other Nonoperating Income (Over) or under collected beyond $40 million Range 3 [Member] Range 3 Award Timing Method Award Timing Method [Text Block] Regulation and Rates [Line Items] Regulation and Rates [Line Items] Regulation and Rates [Line Items] Net increase (decrease) in cash, cash equivalents, and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Liabilities: Offsetting Derivative Liabilities [Abstract] Forecast Forecast [Member] Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Amortization of net loss (gain) Defined Benefit Plan, Amortization of Gain (Loss) New Accounting Pronouncements Accounting Standards Update and Change in Accounting Principle [Text Block] Net income (loss) Net Income (loss) Net income (loss) Net Income (Loss) Attributable to Parent Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Debt issuance costs Unamortized Debt Issuance Expense Common Stock Shares Issued Not Disclosed Common Stock Shares Issued Not Disclosed Common Stock Shares Issued Not Disclosed Statement [Table] Statement [Table] Public Utilities, Approved Return on Equity, Percentage Public Utilities, Approved Return on Equity, Percentage Restatement Determination Date: Restatement Determination Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Wholesale Wholesale [Member] Wholesale Total operating revenue Revenue Regulated and Unregulated Operating Revenue Gross Amount Recognized in the Statement of Financial Position Derivative Asset, Subject to Master Netting Arrangement, before Offset Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Power contract acquisition adjustment gain Power Contract Acquisition Adjustment Non Current Current Fair Value adjustment of the power contract acquisitions, that will be recognized as income after one year. Operating revenue: Revenues [Abstract] Balance at beginning of period Balance at end of period Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs Posted Collateral Collateral Already Posted, Aggregate Fair Value Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Fair Value measurement, sensitivity analysis, hypothetical increase or decrease of market prices, result on fair value Fair Value measurement, sensitivity analysis, hypothetical increase or decrease of market prices, result on fair value, percent Fair Value measurement, sensitivity analysis, hypothetical increase or decrease of market prices, result on fair value, percent Financial Support to Nonconsolidated Legal Entity [Domain] Financial Support to Nonconsolidated Legal Entity [Domain] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract]