Income Statement [Abstract] Statement [Table] Statement [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Westar Energy Inc [Member] Westar Energy Inc [Member] Utility operating in Kansas. KCPL [Member] KCPL [Member] Kansas City Power & Light Company [Member] Statement [Line Items] Statement [Line Items] OPERATING REVENUES Electric Revenue OPERATING EXPENSES: Costs and Expenses [Abstract] Fuel and purchased power FuelAndPurchasedPower Amount of operating expense for fuel and purchased power used by regulated operation SPP network transmission costs Cost of Transmission Operating and maintenance Utilities Operating Expense, Maintenance and Operations Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Taxes other than income tax Taxes, Miscellaneous Total Operating Expenses Costs and Expenses INCOME FROM OPERATIONS Operating Income (Loss) OTHER INCOME (EXPENSE): Other Income and Expenses [Abstract] Investment earnings Investment Income, Nonoperating Other income Other Nonoperating Income Other expense Other Nonoperating Expense Total Other Income (Expense), Net Nonoperating Income (Expense) Interest expense Interest Expense INCOME BEFORE INCOME TAXES Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Equity in earnings of equity method investees, net of income taxes Income (Loss) from Equity Method Investments NET INCOME Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Less: Net income attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest NET INCOME Net Income (Loss) Attributable to Parent Basic earnings per common share (in dollars per share) Earnings Per Share, Basic Diluted earnings per common share (in dollars per share) Earnings Per Share, Diluted Average number of basic common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Average number of diluted common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted COMPREHENSIVE INCOME Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] OTHER COMPREHENSIVE INCOME: Other Comprehensive Income (Loss), Net of Tax [Abstract] Derivative hedging activity Derivative Hedging Activity [Abstract] Derivative Hedging Activity [Abstract] Reclassification to expenses, net of tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Derivative hedging activity, net of tax Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Total other comprehensive income Other Comprehensive Income (Loss), Net of Tax Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Equity compensation expense and associated income tax benefits Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Performance share activity Schedule of Nonvested Performance-based Units Activity [Table Text Block] Restricted stock activity Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Restricted stock unit activity Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block] Retirement Benefits [Abstract] Schedule of Net Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Statement of Stockholders' Equity [Abstract] Dividends declared on common stock (in dollars per share) Common Stock, Dividends, Per Share, Declared Accounting Policies [Abstract] Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] As Previously Reported [Member] Scenario, Previously Reported [Member] Restatement Adjustment [Member] Restatement Adjustment [Member] Error Corrections and Prior Period Adjustments Restatement [Line Items] Error Corrections and Prior Period Adjustments Restatement [Line Items] Decrease in pension and post-retirement liability Liability, Defined Benefit Plan, Noncurrent Increase in other long-term liabilities Other Liabilities, Noncurrent Amortization of other Amortization of Other Deferred Charges Amortization of deferred refueling outage Amortization Of Deferred Refueling Outage Costs Amortization Of Deferred Refueling Outage Costs Deferred income taxes, net Deferred Income Tax Expense (Benefit) Investment tax credit amortization Investment Tax Credit Amortization The amount deducted from an entities' taxes, reflecting a percentage of an amount invested in certain assets spread over the useful life of those assets; the part related to the amortization of investment tax credits. Net deferred income taxes and credits Deferred Income Taxes and Tax Credits Payments for asset retirement obligations Payments For Asset Retirement Obligations Payments For Asset Retirement Obligations Other Other Noncash Income (Expense) Fuel inventory and supplies Increase (Decrease) In Energy Related Inventory Increase (Decrease) In Energy Related Inventory Fuel inventories Increase (Decrease) in Fuel Inventories Materials and supplies Increase (Decrease) in Raw Materials, Packaging Materials and Supplies Inventories Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Accrued interest Increase (Decrease) in Interest Payable, Net Other current liabilities Increase (Decrease) in Other Current Liabilities Changes in other assets Increase (Decrease) in Other Operating Assets Changes in other liabilities Increase (Decrease) in Other Operating Liabilities Deferred refueling outage costs Increase Decrease In Deferred Refueling Outage Costs The increase (decrease) in deferred refueling outage costs. Pension and post-retirement benefit obligations Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits Fuel recovery mechanisms Increase (Decrease) in over (under) Energy Recovery Cash Flows from Operating Activities Net Cash Provided by (Used in) Operating Activities Additions to property, plant and equipment Payments to Acquire Property, Plant, and Equipment Utility capital expenditures Payments to Acquire Property, Plant, and Equipment, Utility Payments to Acquire Property, Plant, and Equipment, Utility Allowance for borrowed funds used during construction Allowance For Borrowed Funds Used During Construction The component of the allowance for funds used during construction during the period based on the interest rate on borrowed funds used in financing the construction of regulated assets. Other investing activities Payments for (Proceeds from) Other Investing Activities Cash Flows from (used in) Investing Activities Net Cash Provided by (Used in) Investing Activities Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table] Geographic Distribution [Axis] Geographic Distribution [Axis] Geographic Distribution [Domain] Geographic Distribution [Domain] Geographic Distribution, Domestic [Member] Geographic Distribution, Domestic [Member] Other Evergy [Member] Other Evergy [Member] Other Evergy [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Decommissioning Trust Assets [Member] Decommissioning Trust Assets [Member] Decommissioning Trust Assets [Member] Equity Securities [Member] Equity Securities [Member] Equity Securities - Fourth Fund [Member] Equity Securities - Fourth Fund [Member] Equity Securities - Fourth Fund [Member] Equity Securities - Fifth Fund [Member] Equity Securities - Fifth Fund [Member] Equity Securities - Fifth Fund [Member] Alternative Investment Fund [Member] Alternative Investment Fund [Member] Alternative Investment Fund [Member] Real Estate Funds [Member] Real Estate Funds [Member] Core Bond Fund [Member] Core Bond Fund [Member] Core Bond Fund [Member] Debt Equity Other Fund [Member] Debt Equity Other Fund [Member] Debt Equity Other Fund [Member] Rabbi Trusts [Member] Rabbi Trusts [Member] Rabbi Trusts [Member] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] NAV, Fair Value Alternative Investment, Fair Value Disclosure NAV, Unfunded Commitments Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments NAV, Length of Settlement Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period NAV, Number of funds Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Number Of Funds Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Number Of Funds NAV, Number of funds making distributions Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Number Of Funds Making Distributions Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Number Of Funds Making Distributions NAV, Extension term Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Extension Term Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Extension Term NAV, Number of extensions Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Number Of Extensions Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Number Of Extensions Short-term Borrowings and Short-term Bank Lines of Credit [Abstract] Schedule of Short-term Debt [Table] Schedule of Short-term Debt [Table] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Wester Energy Revolving Credit Facility One [Member] Wester Energy Revolving Credit Facility One [Member] Wester Energy Revolving Credit Facility One [Member] Wester Energy Revolving Credit Facility Two [Member] Wester Energy Revolving Credit Facility Two [Member] Wester Energy Revolving Credit Facility Two [Member] Evergy [Member] Evergy [Member] Evergy [Member] Great Plains Energy [Member] Great Plains Energy [Member] Information on Great Plains Energy. KCP&L Receivables Company [Member] KCP&L Receivables Company [Member] KCP&L Receivables Company [Member] GMO Receivables Company [Member] GMO Receivables Company [Member] GMO Receivables Company [Member] Kcpl Greater Missouri Operations Member Kcpl Greater Missouri Operations Member Information on KCPL Greater Missouri Operations. Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Commercial Paper [Member] Commercial Paper [Member] Standby Letters of Credit [Member] Standby Letters of Credit [Member] Master Credit Facility [Member] Revolving Credit Facility [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Maximum [Member] Maximum [Member] Minimum [Member] Minimum [Member] Short-term Debt [Line Items] Short-term Debt [Line Items] Line Of Credit, Expired Line Of Credit, Expired Line Of Credit, Expired Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity Debt Instrument, Debt Default, Threshold Debt Instrument, Debt Default, Threshold Debt Instrument, Debt Default, Threshold Debt Instrument, debt to capitalization ratio Debt Instrument, Covenant, Debt to Capitalization Ratio Debt Instrument, Covenant, Debt to Capitalization Ratio Long-term Line of Credit Long-term Line of Credit Line of Credit Facility, Remaining Borrowing Capacity Line of Credit Facility, Remaining Borrowing Capacity Line of Credit Facility, Interest Rate at Period End Line of Credit Facility, Interest Rate at Period End Line of Credit Facility, Covenant Terms Line of Credit Facility, Covenant Terms Credit facility expiration date Line of Credit Facility, Expiration Date Maximum borrowing capacity with transfer of unused commitments Line Of Credit Facility Maximum Borrowing Capacity With Transfer Of Unused Commitments The maximum amount of lending capacity under Great Plains Energy's credit facility if unused commitments are transferred between that credit facility and the credit facilities of KCPL and GMO Maximum transfer of unused commitments Line Of Credit Facility Maximum Transfer Of Unused Commitments The maximum amount of unused commitments that can be transferred between the entity's revolving credit facility and Great Plains Energy's revolving credit facility. Line of Credit Facility, Covenant Compliance Line of Credit Facility, Covenant Compliance Line of Credit Facility, Current Borrowing Capacity Line of Credit Facility, Current Borrowing Capacity Line of Credit Facility, Amount Expired Line of Credit Facility, Amount Expired Line of Credit Facility, Amount Expired Amount of letters of credit outstanding Letters of Credit Outstanding, Amount Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Performance Shares [Member] Performance Shares [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive securities excluded from computation of earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Variable Interest Entities [Member] Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member] Cash paid for (received from): Supplemental Cash Flow Information [Abstract] Interest, net of amounts capitalized Interest Paid Income taxes, net of refunds Income Taxes Paid, Net Non-cash investing transactions: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Property, plant and equipment additions (reductions) Increase (Decrease) In Property, Plant And Equipment Increase (Decrease) In Property, Plant And Equipment Deconsolidation of property, plant and equipment of VIE DeconsolidationOfPropertyPlantAndEquipmentOfVIE Deconsolidation Of Property Plant And Equipment Of VIE Non-cash financing transactions: Other Noncash Investing and Financing Items [Abstract] Issuance of stock for compensation and reinvested dividends Stock Issued Non-cash financing, deconsolidation of VIE NonCashFinancingDeconsolidationOfVIE Non Cash Financing Deconsolidation Of VIE Assets acquired through capital leases Capital Lease Obligations Incurred Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Business Acquisition [Line Items] Business Acquisition [Line Items] One-time bill credits Business Combination, Acquisition Related Costs, One-Time Bill Credits Business Combination, Acquisition Related Costs, One-Time Bill Credits Annual bill credits Business Combination, Acquisition Related Costs, Annual Bill Credits Business Combination, Acquisition Related Costs, Annual Bill Credits Total impact to operating revenues Business Combination, Acquisition Related Costs, Customer Bill Credits Business Combination, Acquisition Related Costs, Customer Bill Credits Charitable contributions and community support Business Combination, Acquisition Related Costs, Charitable Contributions And Community Support Business Combination, Acquisition Related Costs, Charitable Contributions And Community Support Voluntary severance and accelerated equity compensation Business Combination, Acquisition Related Costs, Voluntary Severance And Accelerated Equity Compensation Business Combination, Acquisition Related Costs, Voluntary Severance And Accelerated Equity Compensation Other transaction and transition costs Business Combination, Acquisition Related Costs, Other Transaction And Transition Costs Business Combination, Acquisition Related Costs, Other Transaction And Transition Costs Reallocation and deferral of merger transition costs Business Combination, Acquisition Related Costs, Reallocation And Deferred Transaction Costs Business Combination, Acquisition Related Costs, Reallocation And Deferred Transaction Costs Total impact to operating and maintenance expense Business Combination, Acquisition Related Costs, Impact To Operating And Maintenance Expense Business Combination, Acquisition Related Costs, Impact To Operating And Maintenance Expense Total Business Combination, Acquisition Related Costs, Charges And Deferrals Business Combination, Acquisition Related Costs, Charges And Deferrals Equity Interest Type [Axis] Equity Interest Type [Axis] Equity Interest Issued or Issuable, Type [Domain] Equity Interest Issued or Issuable, Type [Domain] Common Stock [Member] Common Stock [Member] Stock Compensation Plan [Member] Stock Compensation Plan [Member] Common stock outstanding (in shares) Common Stock, Shares, Outstanding Awards outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Great Plains Energy shares to be converted to Evergy shares (in shares) Business Combination, Number Of Shares Converted Business Combination, Number Of Shares Converted Exchange ratio Business Acquisition, Conversion Ratio Business Acquisition, Conversion Ratio Number of shares issued (in shares) Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Closing price (in dollars per share) Business Acquisition, Share Price Fair value of shares issued Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Total purchase price Business Combination, Consideration Transferred Organization, Consolidation and Presentation of Financial Statements [Abstract] Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Revenue from Contract with Customer [Abstract] Revenue Revenue from Contract with Customer [Text Block] Asset Retirement Obligation Disclosure [Abstract] Asset Retirement Obligations Asset Retirement Obligation Disclosure [Text Block] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Retained Earnings [Member] Retained Earnings [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] AOCI - Net gains (losses) on cash flow hedges [Member] AOCI Including Portion Attributable to Noncontrolling Interest [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning balance (in shares) Shares, Outstanding Beginning balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Net income (loss) Cumulative effect of adoption of ASU 2016-09 Cumulative Effect of New Accounting Principle in Period of Adoption Issuance of stock Stock Issued During Period, Value, New Issues Issuance of stock (in shares) Stock Issued During Period, Shares, New Issues Issuance of stock to Great Plains Energy shareholders (in shares) Stock Issued During Period, Shares, Acquisitions Issuance of stock to Great Plains Energy shareholders Stock Issued During Period, Value, Acquisitions Issuance of restricted common stock (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Issuance of stock for compensation and reinvested dividends (in shares) Stock Issued During Period, Shares, Dividend Reinvestment Plan And Share-Based Compensation Stock Issued During Period, Shares, Dividend Reinvestment Plan And Share-Based Compensation Issuance of stock for compensation and reinvested dividends Stock Issued During Period, Value, Dividend Reinvestment Plan And Share-Based Compensation Stock Issued During Period, Value, Dividend Reinvestment Plan And Share-Based Compensation Tax withholding related to stock compensation Adjustments Related to Tax Withholding for Share-based Compensation Dividends declared on common stock Dividends, Common Stock, Cash Dividend equivalents declared Dividends, Share-based Compensation Stock compensation expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Deconsolidation of noncontrolling interests Noncontrolling Interest, Decrease from Deconsolidation Distributions to shareholders of noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Repurchase of common stock Stock Repurchased and Retired During Period, Value Repurchase of common stock Stock Repurchased During Period, Shares Repurchase of common stock Stock Repurchased During Period, Value Stock cancelled pursuant to Amended Merger Agreement (in shares) Stock Canceled During Period, Shares Stock Canceled During Period, Shares Stock cancelled pursuant to Amended Merger Agreement Stock Canceled During Period, Value Stock Canceled During Period, Value Derivative hedging activity, net of tax Other Stockholders' Equity, Other Ending balance (in shares) Ending balance Jointly Owned Utility Plant [Axis] Jointly Owned Utility Plant [Axis] Jointly Owned Utility Plant [Domain] Jointly Owned Utility Plant [Domain] Wolf Creek [Member] Jointly Owned Nuclear Power Plant [Member] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Beginning balance, January 1 Asset Retirement Obligation Liabilities assumed upon merger with Great Plains Energy Asset Retirement Obligation, Liabilities Assumed Asset Retirement Obligation, Liabilities Assumed Liabilities incurred during the year Asset Retirement Obligation, Liabilities Incurred Revision in timing and/or estimates Asset Retirement Obligation, Revision of Estimate Settlements Asset Retirement Obligation, Liabilities Settled Accretion Asset Retirement Obligation, Accretion Expense Ending balance Less: current portion Asset Retirement Obligation, Current Total noncurrent asset retirement obligation Asset Retirement Obligations, Noncurrent Jointly owned utility plant, proportionate ownership share Jointly Owned Utility Plant, Proportionate Ownership Share Receivables [Abstract] KCPL Greater Missouri Operations [Member] Other receivables, contracts with customers OtherReceivablesContractsWithCustomers The amount of other receivables resulting from contracts with customers. Sale Of Accounts Receivable - KCPL and GMO Sale Of Accounts Receivable - KCPL and GMO [Line Items] [Abstract] Sale Of Accounts Receivable - KCPL and GMO [Line Items] [Abstract] Accounts receivable pledged as collateral Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount Collateralized note payable Transfers Accounted for as Secured Borrowings, Associated Liabilities, Carrying Amount Maximum amount of outstanding principal under receivables agreement from mid-November to mid-June MaximumAmountOfOutstandingPrincipalUnderReceivablesAgreementFromMidNovToMidJun MaximumAmountOfOutstandingPrincipalUnderReceivablesAgreementFromMidNovToMidJun Maximum amount of outstanding principal under receivables agreement Maximum Amount Of Outstanding Principal Under Receivables Agreement Maximum amount of outstanding principal under receivables agreement Maximum amount of outstanding principal under receivables agreement from mid-June to mid-November MaximumAmountOfOutstandingPrincipalUnderReceivablesAgreementFromMidJunToMidNov MaximumAmountOfOutstandingPrincipalUnderReceivablesAgreementFromMidJunToMidNov Stockholders' Equity Note [Abstract] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Great Plains Energy 401(k) Savings Plan and Wester Energy Inc Employees 401(k) Savings Plan Great Plains Energy 401(k) Savings Plan and Wester Energy Inc Employees 401(k) Savings Plan [Member] Great Plains Energy 401(k) Savings Plan and Wester Energy Inc Employees 401(k) Savings Plan [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Westar Energy and KCP&L Receivables Company [Member] Westar Energy and KCP&L Receivables Company [Member] Westar Energy and KCP&L Receivables Company [Member] Common Shareholders' Equity [Line Items] Common Shareholders' Equity [Line Items] Common Shareholders' Equity [Line Items] Common stock - shares authorized (in shares) Common Stock, Shares Authorized Preferred stock - shares authorized (in shares) Preferred Stock, Shares Authorized Shares available for future issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Number of shares authorized to be repurchased (in shares) Stock Repurchase Program, Number of Shares Authorized to be Repurchased Stock Repurchased and Retired During Period, Value Stock repurchased and retired during period under repurchase plan, value StockRepurchasedAndRetiredDuringPeriodUnderRepurchasePlanValue Equity impact of the value of stock that has been repurchased and retired during the period under the repurchase plan. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital). Stock Repurchased and Retired During Period, Shares Stock Repurchased and Retired During Period, Shares Accelerated Share Repurchases, Settlement (Payment) or Receipt Accelerated Share Repurchases, Settlement (Payment) or Receipt Partial Settlement Of Accelerated Share Repurchase Agreement, Shares Partial Settlement Of Accelerated Share Repurchase Agreement, Shares Partial Settlement Of Accelerated Share Repurchase Agreement, Shares Restriction on payment of dividends, minimum ratio of total capitalization Restriction on Payment of Dividends, Minimum Ratio of Equity to Capitalization Restriction on Payment of Dividends, Minimum Ratio of Equity to Capitalization Retained earnings restrictions Equity Restrictions Restricted net assets of subsidiaries Amount of Restricted Net Assets for Consolidated and Unconsolidated Subsidiaries Additional Shares From Early ASR Settlement Additional Shares From Early ASR Settlement Additional Shares From Early ASR Settlement Carrying value and fair value of debt instruments Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block] Fair value of assets and liabilities Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Fair value investments, entities that calculate NAV Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table Text Block] Fair value recurring gain (loss) included in earnings Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Table Text Block] Inventory, Current [Table] Inventory, Current [Table] Inventory [Line Items] Inventory [Line Items] Fuel inventory Energy Related Inventory, Coal Supplies Energy Related Inventory, Supplies Energy Related Inventory, Supplies Fuel inventory and supplies Energy Related Inventory Guarantees [Abstract] Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Direct Guarantee [Member] Financial Guarantee [Member] Guarantee of Indebtedness of Others [Member] Guarantee of Indebtedness of Others [Member] Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Long-term Debt [Member] Long-term Debt [Member] Guarantor Obligations [Line Items] Guarantor Obligations [Line Items] Origin and purpose Guarantor Obligations, Origin and Purpose Maximum exposure Guarantor Obligations, Maximum Exposure, Undiscounted Obligations term Guarantor Obligations, Term Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Accounts, Notes, Loans and Financing Receivable by Receivable Type [Axis] Receivable Type [Axis] Receivable [Domain] Receivable [Domain] Trade Accounts Receivable [Member] Trade Accounts Receivable [Member] Accounts, Notes, Loans and Financing Receivable by Billing Status, Type [Axis] Billing Status, Type [Axis] Receivables Billing Status [Domain] Receivables Billing Status [Domain] Billed Revenues [Member] Billed Revenues [Member] Unbilled Revenues [Member] Unbilled Revenues [Member] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Customer accounts receivable Accounts Receivable, Gross, Current Other receivables Other Receivables, Gross, Current Allowance for doubtful accounts Allowance for Doubtful Accounts Receivable, Current Total Receivables, Net, Current Shareholders' Equity Stockholders' Equity Note Disclosure [Text Block] Pension Plans and Other Employee Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] Statement of Financial Position [Abstract] Variable Interest Entities [Member] Variable Interest Entity, Primary Beneficiary [Member] ASSETS Assets [Abstract] CURRENT ASSETS: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Receivables, net Related party receivables Accounts Receivable, Related Parties, Current Fuel inventory and supplies Income taxes receivable Income Taxes Receivable, Current Regulatory assets Regulatory Assets, Current Prepaid expenses and other assets Prepaid Expense and Other Assets, Current Total Current Assets Assets, Current PROPERTY, PLANT AND EQUIPMENT, NET Property, Plant and Equipment, Net OTHER ASSETS: Investments And Other Assets [Abstract] Regulatory assets Regulatory Assets, Noncurrent Nuclear decommissioning trust fund Decommissioning Fund Investments Goodwill Goodwill Other Other Assets, Noncurrent Total Other Assets Investments And Other Assets The total of investments and other long-term assets. TOTAL ASSETS Assets LIABILITIES AND EQUITY Liabilities and Equity [Abstract] CURRENT LIABILITIES: Liabilities, Current [Abstract] Current maturities of long-term debt Long-term Debt, Current Maturities Notes payable and commercial paper Short-term Bank Loans and Notes Payable Accounts payable Accounts Payable, Current Related party payables Accounts Payable, Related Parties, Current Accrued dividends Dividends Payable, Current Accrued taxes Taxes Payable, Current Accrued interest Interest Payable, Current Regulatory liabilities Regulatory Liability, Current Other Other Liabilities, Current Total Current Liabilities Liabilities, Current LONG-TERM LIABILITIES: Liabilities, Noncurrent [Abstract] Long-term debt, net Long-term Debt, Excluding Current Maturities Deferred income taxes Deferred Tax Liabilities, Net, Noncurrent Unamortized investment tax credits Accumulated Deferred Investment Tax Credit Regulatory liabilities Regulatory Liability, Noncurrent Pension and post-retirement liability Asset retirement obligations Other Total Long-Term Liabilities Liabilities, Noncurrent Commitments and Contingencies (Note 12) Commitments and Contingencies EQUITY: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Shareholders' Equity: Stockholders' Equity Attributable to Parent [Abstract] Common stock Common Stock, Value, Issued Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Shareholders' Equity Stockholders' Equity Attributable to Parent Noncontrolling Interests Stockholders' Equity Attributable to Noncontrolling Interest Total Equity TOTAL LIABILITIES AND EQUITY Liabilities and Equity New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2017-12 [Member] Accounting Standards Update 2017-12 [Member] Accounting Standards Update 2017-12 [Member] Accounting Standards Update 2017-07 [Member] Accounting Standards Update 201707 [Member] Accounting Standards Update 2017-07 [Member] Effect of Change [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Operating and maintenance expense Total operating expenses Income from operations Other expense Total other income (expense), net Debt Disclosure [Abstract] Long-Term Debt Long-term Debt [Text Block] Summary of Reclassifications Schedule of Error Corrections and Prior Period Adjustments [Table Text Block] Schedule of Fuel Inventory and Supplies Schedule of Inventory, Current [Table Text Block] Summary of Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Supplemental Cash Flow Information Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Schedule of Retrospective Adjustments Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block] Shareholder's equity Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract] Common stock - par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock - shares issued (in shares) Common Stock, Shares, Issued Receivables Loans Notes Trade And Other Receivables Disclosure And Transfers And Servicing Of Financial Asset [Text Block] Includes disclosure of claims held for amounts due a company. Examples include trade accounts receivables, notes receivables, loans receivables. Also provides the disclosures pertaining to a transferor's continuing involvement in financial assets that it has transferred in a securitization or asset-backed financing arrangements. Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Electric Utility Customer Class Residential [Member] Electric Utility Customer Class Residential [Member] Residential customer class from which revenues are generated by the regulated sale of electricity [Member] Electric Utility Customer Class Commercial [Member] Electric Utility Customer Class Commercial [Member] Commercial customer class from which revenues are generated by the regulated sale of electricity [Member] Electric Utility Customer Class Industrial [Member] Electric Utility Customer Class Industrial [Member] Industrial customer class from which revenues are generated by the regulated sale of electricity [Member] Electric Utility Customer Class Other Retail [Member] Electric Utility Customer Class Other Retail [Member] Other retail customer class from which revenues are generated by the regulated sale of electricity [Member] Electric Utility Customer Class Total Electric Retail [Member] Electric Utility Customer Class Total Electric Retail [Member] Total electric retail customer class from which revenues are generated by the regulated sale of electricity [Member] Electric Utility Customer Class Wholesale [Member] Electric Utility Customer Class Wholesale [Member] Wholesale customer class from which revenues are generated by the sale of wholesale power and capacity when the power is not required for customers within service territory [Member] Electric Utility Customer Class Transmission [Member] Electric Utility Customer Class Transmission [Member] Transmission customer class from which revenues are generated by the use of KCP&L's and GMO's transmission network by the SPP on behalf of other power providers [Member] Electric Utility Customer Class Industrial Steam [Member] Electric Utility Customer Class Industrial Steam [Member] Industrial steam customer class from which revenues are generated by the regulated sale of industrial steam to GMO's steam customers [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Electric Utility Segment [Member] Electric Utility Segment [Member] Electric Utility Segment [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Total revenue from contracts with customers Revenue from Contract with Customer, Excluding Assessed Tax Other OtherRevenue Revenue other than from contracts with customers. Operating revenues Merger of Great Plains Energy and Westar Energy Business Combination Disclosure [Text Block] Principles of Consolidation Consolidation, Policy [Policy Text Block] Fuel Inventory and Supplies Inventory, Policy [Policy Text Block] Earnings Per Share Earnings Per Share, Policy [Policy Text Block] New Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Organization and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] Regulated Operations [Abstract] Regulatory Proceedings [Table] Public Utilities General Disclosures [Table] Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Domain] Public Utilities, Regulatory Proceeding [Domain] Transmission Delivery Charge [Member] Transmission Delivery Charge [Member] Transmission Delivery Charge [Member] 2018 Rate Case Proceedings [Member] 2018 Rate Case Proceedings [Member] 2018 Rate Case Proceedings [Member] Merger Settlement Agreement [Member] Merger Settlement Agreement [Member] Merger Settlement Agreement [Member] FERC Proceedings [Member] FERC Proceedings [Member] FERC Proceedings [Member] FERC 2019 TFR Proceeding [Member] FERC2019TFRProceeding [Member] FERC 2019 TFR Proceeding Regulatory Agency [Axis] Regulatory Agency [Axis] Regulatory Agency [Domain] Regulatory Agency [Domain] Missouri Public Service Commission [Member] MissouriPublicServiceCommission [Member] Information related to the Public Service Commission of the State of Missouri. Kansas Corporation Commission [Member] Kansas Corporation Commission [Member] Information related to the State Corporation Commission of the State of Kansas. Federal Energy Regulatory Commission [Member] Federal Energy Regulatory Commission [Member] Federal Energy Regulatory Commission [Member] Regulatory Proceedings [Line Items] Public Utilities, General Disclosures [Line Items] Anticipated annual revenue increase authorized PublicUtilitiesApprovedRateIncreaseDecreaseAnticipatedAmount Amount of public utility's approved rate increase (decrease) by regulatory agency anticipated to be received by the utility following the approval of the utility's tariff sheets. Annual revenue increase (decrease), requested Public Utilities, Requested Rate Increase (Decrease), Amount Annual revenue increase (decrease), approved Public Utilities, Approved Rate Increase (Decrease), Amount Revised annual revenue increase, requested Public Utilities, Requested Rate Increase (Decrease), Amended, Amount Return on equity, requested Public Utilities, Requested Return on Equity, Percentage Return on equity, approved Public Utilities, Approved Return on Equity, Percentage Rate-making equity ratio, requested Public Utilities, Requested Equity Capital Structure, Percentage Rate-making equity ratio, approved Public Utilities, Approved Equity Capital Structure, Percentage Production tax credit, expiration period Public Utilities, Production Tax Credit, Expiration Period Public Utilities, Production Tax Credit, Expiration Period Annual revenue increase (decrease) related to rebasing, requested Public Utilities Requested Rate Increase Decrease Amount, Rebasing Fuel Purchased Power Expense And Property Tax Expense Amount of public utility's requested rate increase (decrease) amount, the portion related to the rebasing of fuel, purchased power expense and/or property tax expense Annual revenue increase (decrease) related to rebasing, approved PublicUtilitiesApprovedRateIncreaseDecreaseAmountRebasingFuelPurchasedPowerExpenseAndPropertyTaxExpense Amount of public utility's approved rate increase (decrease), the portion related to the rebasing of fuel, purchased power expense and/or property tax expense Increase (decrease) in depreciation expense, requested Public Utilities, Requested Rate Increase (Decrease), Amount, Depreciation Expense Public Utilities, Requested Rate Increase (Decrease), Amount, Depreciation Expense Increase (decrease) in depreciation expense, approved PublicUtilitiesApprovedRateIncreaseDecreaseAmountDepreciationExpense Public Utilities, Approved Rate Increase (Decrease), Amount, Depreciation Expense Recovery of wholesale contract, requested Public Utilities, Requested Rate Increase (Decrease), Amount, Recovery Of Wholesale Contract Public Utilities, Requested Rate Increase (Decrease), Amount, Recovery Of Wholesale Contract Recovery of wholesale contract, approved PublicUtilitiesApprovedRateIncreaseDecreaseAmountRecoveryOfWholesaleContract Public Utilities, Approved Rate Increase (Decrease), Amount, Recovery Of Wholesale Contract One-time bill credit, requested Public Utilities, Requested Rate Increase (Decrease), Amount, One-Time Bill Credit Public Utilities, Requested Rate Increase (Decrease), Amount, One-Time Bill Credit One-time bill credit, approved PublicUtilitiesApprovedRateIncreaseDecreaseAmountOneTimeBillCredit Public Utilities Approved Rate Increase (Decrease), Amount, One-Time Bill Credit Annual revenue increase (decrease), requested, not including rebasing Public Utilities Requested Rate Increase Decrease Amount Not Including Rebasing Fuel Purchased Power Expense And Property Tax Expense Amount of public utility's requested rate increase (decrease) with regulatory agency, not including rebasing fuel, purchased power expense and/or property tax expense Annual revenue increase (decrease), approved, not including rebasing PublicUtilitiesApprovedRateIncreaseDecreaseAmountNotIncludingRebasingFuelPurchasedPowerExpenseAndPropertyTaxExpense Amount of public utility's approved rate increase (decrease) with regulatory agency, not including rebasing fuel, purchased power expense and/or property tax expense Recommended return on equity Commission Staff Recommended Return On Equity Percentage Percentage of return on equity recommended by staff of the state commission. Recommended increase (decrease) to revenues Commission Staff Recommended Rate Increase Decrease Amount Amount of rate increase (decrease) recommended by staff of the state commission. Expected increase in annual transmission revenues Public Utilities, Expected Annual Transmissions Revenue, Increase (Decrease), Amount Public Utilities, Expected Annual Transmissions Revenue, Increase (Decrease), Amount Regulatory liability Regulatory Liabilities Annual transmissions revenue estimated amount of increase (decrease) over prior year PublicUtilitiesEstimatedAnnualTransmissionsRevenueIncreaseDecreaseOverPriorYearAmount Public utilities, estimated annual transmissions revenue amount of increase (decrease) over prior year Public Utilities, Requested Rate Increase (Decrease) Following Stipulation, Amount PublicUtilitiesRequestedRateIncreaseDecreaseAmountPerStipulation Amount of public utility's requested rate increase (decrease) with regulatory agency following entry into a stipulation and agreement with commission staff and/or other intervenors. Public Utilities, Requested Return on Equity Following Stipulation PublicUtilitiesRequestedReturnOnEquityPerStipulation Requested return on equity requested with regulatory agency following entry into a stipulation and agreement with commission staff and/or other intervenors Public Utilities, Requested Rate-Making Equity Ratio Following Stipulation PublicUtilitiesRequestedRateMakingEquityRatioPerStipulation Requested rate-making equity ratio requested with regulatory agency following entry into a stipulation and agreement with commission staff and/or other intervenors. Operating revenues Business Acquisition, Pro Forma Revenue Net income attributable to Evergy, Inc. Business Acquisition, Pro Forma Net Income (Loss) Basic earnings per common share (in dollars per share) Business Acquisition, Pro Forma Earnings Per Share, Basic Diluted earnings per common share (in dollars per share) Business Acquisition, Pro Forma Earnings Per Share, Diluted Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Kansas Gas And Electric Company [Member] Kansas Gas And Electric Company [Member] Kansas Gas And Electric Company [Member] Jeffrey Energy Center [Member] Jeffrey Energy Center [Member] Jeffrey Energy Center [Member] La Cygne Unit 2 [Member] La Cygne Unit 2 [Member] La Cygne Unit 2 [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] VIE ownership percentage Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Property, plant and equipment Income Tax Disclosure [Abstract] Income Tax Disclosure [Text Block] Income Tax Disclosure [Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted Stock Units (RSUs) [Member] Restricted Stock Units (RSUs) [Member] Restricted Stock [Member] Restricted Stock [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award Accelerated Compensation Cost Equity compensation expense Allocated Share-based Compensation Expense Income tax (expense) benefit Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Expected volatility, minimum (in hundredths) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum Expected volatility, maximum (in hundredths) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum Expected dividend yield (in hundredths) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Risk-free interest rate, minimum (in hundredths) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum Risk-free interest rate, maximum (in hundredths) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Beginning balance (in shares) Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Converted Great Plains Energy award upon merger (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Added from Merger Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Added from Merger Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Ending balance (in shares) Weighted average beginning balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Weighted average granted (in dollars 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 Weighted average converted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Added from Merger, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Added from Merger, Weighted Average Grant Date Fair Value Weighted average vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Weighted average forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Weighted average ending balance (in dollars per share) Total unrecognized compensation expense Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized 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 Remaining weighted-average contractual term (in years) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Domain] Initial Application Period Cumulative Effect Transition [Domain] Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Accounting Standards Update 2016-15 - Corporate Owned Life Insurance, Premiums [Member] Accounting Standards Update 2016-15 - Corporate Owned Life Insurance, Premiums [Member] Accounting Standards Update 2016-15 - Corporate Owned Life Insurance, Premiums [Member] Accounting Standards Update 2016-15 - Corporate Owned Life Insurance, Settlements [Member] Accounting Standards Update 2016-15 - Corporate Owned Life Insurance, Settlements [Member] Accounting Standards Update 2016-15 - Corporate Owned Life Insurance, Settlements [Member] Accounting Standards Update 2016-18 [Member] Accounting Standards Update 2016-18 [Member] Accounting Standards Update 2014-09 [Member] Accounting Standards Update 2014-09 [Member] Cash flows provided by (used in) operating activities Cash flows provided by (used in) investing activities Cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Operating revenues Taxes other than income tax Schedule of Change in Asset Retirement Obligation Schedule of Change in Asset Retirement Obligation [Table Text Block] Statement of Cash Flows [Abstract] Restricted cash Restricted Cash and Cash Equivalents Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension Plans, Defined Benefit [Member] Pension Plan [Member] Other Postretirement Benefit Plans, Defined Benefit [Member] Other Postretirement Benefits Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Components of net periodic benefit costs [Abstract] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Prior service cost Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Recognized net actuarial (gain)/loss Defined Benefit Plan, Amortization of Gain (Loss) Net periodic benefit costs before regulatory adjustment Net period benefit costs before regulatory adjustment The total amount of net periodic benefit cost for defined benefit plans for the period before regulatory adjustment. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments. Regulatory adjustment Defined Benefit Plan Regulatory Adjustment Increase (decrease) in net periodic benefit costs related to regulatory adjustments. Net periodic benefit costs Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Contributions by employer Defined Benefit Plan, Plan Assets, Contributions by Employer Contributions by employer, remainder of fiscal year Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Adjustments to reconcile income to net cash from operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Amortization of nuclear fuel Amortization of Nuclear fuel The noncash expense, not otherwise specified in the taxonomy, charged against earnings in the period to allocate the cost of nuclear fuel over the operating cycle of the nuclear plant. Amortization of deferred regulatory gain from sale leaseback Amortization Of Sale Leaseback Transaction Amortization Of Sale Leaseback Transaction Amortization of corporate-owned life insurance Amortization Of Corporate Owned Life Insurance Amortization Of Corporate Owned Life Insurance Non-cash compensation Share-based Compensation Allowance for equity funds used during construction Increase (Decrease) in Allowance for Equity Funds Used During Construction Equity in earnings of equity method investees, net of income taxes Changes in working capital items: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Accounts receivable pledged as collateral Increase decrease in accounts receivable pledged as collateral The increase (decrease) during the reporting period in the amount due within one year (or one business cycle) from customers for the credit sale of goods and services where those amounts have been pledged as collateral. Accounts payable Increase (Decrease) in Accounts Payable Accrued taxes Increase (Decrease) in Accrued Taxes Payable CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities [Abstract] Cash acquired from the merger with Great Plains Energy Cash Acquired from Acquisition Purchase of securities - trusts Payments to Acquire Investments to be Held in Decommissioning Trust Fund Sale of securities - trusts Proceeds from Decommissioning Trust Fund Assets Investment in corporate-owned life insurance Purchase Of Corporate Owned Life Insurance Purchase Of Corporate Owned Life Insurance Proceeds from investment in corporate-owned life insurance Proceeds from Life Insurance Policy Proceeds from settlement of interest rate swap Proceeds from Derivative Instrument, Financing Activities CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Short term debt, net Proceeds from (Repayments of) Short-term Debt Collateralized short-term borrowings, net Proceeds From Issuance Of Collateralized Debt Proceeds From Issuance Of Collateralized Debt Proceeds from long-term debt Proceeds from Issuance of Long-term Debt Retirements of long-term debt Repayments of Long-term Debt Retirements of Long Term Debt Of VIEs Retirements of Long Term Debt Of VIEs Retirements of Long Term Debt Of VIEs Repayment of capital leases Repayments of Long-term Capital Lease Obligations Borrowings against cash surrender value of corporate-owned life insurance Proceeds From Borrowings Against Corporate Owned Life Insurance Proceeds From Borrowings Against Corporate Owned Life Insurance Repayment of borrowings against cash surrender value of corporate-owned life insurance Repayments Of Borrowings Against Corporate Owned Life Insurance Repayments Of Borrowings Against Corporate Owned Life Insurance Issuance of common stock Proceeds from Issuance of Common Stock Distributions to shareholders of noncontrolling interests Payments to Noncontrolling Interests Cash dividends paid Payments of Dividends Repurchase of common stock Payments for Repurchase of Common Stock Other financing activities Proceeds from (Payments for) Other Financing Activities Cash Flows (used in) Financing Activities Net Cash Provided by (Used in) Financing Activities NET CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect CASH, CASH EQUIVALENTS AND RESTRICTED CASH: Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect [Abstract] Beginning of period End of period Short-term Borrowings and Short-term Bank Lines of Credit Short-term Debt [Text Block] Current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets Property, plant and equipment, net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Goodwill Other long-term assets, excluding goodwill Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Total assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Current liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities Long-term liabilities, excluding long-term debt Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Long-term debt, net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt Total liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Total purchase price Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Rate Matters and Regulation Public Utilities Disclosure [Text Block] Entity information [Abstract] Entity information for DEI Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Reported Value Measurement [Member] Reported Value Measurement [Member] Estimate of Fair Value Measurement [Member] Estimate of Fair Value Measurement [Member] Changes Measurement [Member] Changes Measurement [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] 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] Business Acquisition, Fair Value Adjustment, Long-Term Debt Business Acquisition, Fair Value Adjustment, Long-Term Debt Business Acquisition, Fair Value Adjustment, Long-Term Debt Long-term Debt Long-term Debt, Fair Value Summary Of Accounting Policies [Table] Summary Of Accounting Policies [Table] Summary Of Accounting Policies [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Transource Energy, LLC [Member] Transource Energy, LLC [Member] Transource Energy, LLC Prairie Wind Transmission, LLC [Member] Prairie Wind Transmission, LLC [Member] Prairie Wind Transmission, LLC [Member] Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] GPE Transmission Holding Company, LLC [Member] GPE Transmission Holding Company, LLC [Member] GPE Transmission Holding Company, LLC AEP Transmission Holding Company, LLC [Member] AEP Transmission Holding Company, LLC [Member] AEP Transmission Holding Company, LLC Summary Of Accounting Policies [Line Items] Summary Of Accounting Policies [Line Items] [Line Items] for Summary Of Accounting Policies [Table] Number of active wholly owned subsidiaries Number Of Wholly Owned Subsidiaries Number Of Wholly Owned Subsidiaries Ownership percentage Equity Method Investment, Ownership Percentage Ownership interest Noncontrolling Interest, Ownership Percentage by Parent Owned generating capacity Owned Generating Capacity Owned Generating Capacity Number of customers served Number Of Customers Served Number Of Customers Served Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Electric Plant in Service [Member] Electric Plant In Service [Member] Electric Plant In Service [Member] Construction Work in Progress [Member] Construction in Progress [Member] Nuclear Fuel [Member] Nuclear Fuel [Member] Plant to be Retired [Member] Plant To Be Retired [Member] Plant To Be Retired [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property, plant and equipment, gross Property, Plant and Equipment, Gross Property, plant and equipment, adjustment Property, Plant And Equipment, Adjustment Property, Plant And Equipment, Adjustment Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property, plant and equipment, net Schedule of Components of Income Tax Expense (Benefit) Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of Receivables Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Summary of Bad Debt Expense Impaired Financing Receivables [Table Text Block] Schedule of Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Nonrecurring Adjustment [Axis] Nonrecurring Adjustment [Axis] Nonrecurring Adjustment [Domain] Nonrecurring Adjustment [Domain] Acquisition-related Costs [Member] Acquisition-related Costs [Member] Anticipated Merger With Westar Energy, Inc. [Line Items] Anticipated Acquisition Of Westar Energy, Inc. [Line Items] Anticipated Acquisition Of Westar Energy, Inc. Earnings or Loss of Acquiree since Acquisition Date, Actual Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual Conversion ratio One-time bill credits Public Utilities, Estimated One-Time Bill Credits Public Utilities, Estimated One-Time Bill Credits Additional bill credits Public Utilities, Estimated Additional Bill Credits Public Utilities, Estimated Additional Bill Credits Additional bill credits, annual amount Public Utilities, Estimated Additional Bill Credits, Annual Amount Public Utilities, Estimated Additional Bill Credits, Annual Amount Merger-related savings on current rate cases Public Utilities, Savings On Current Rate Cases Public Utilities, Savings On Current Rate Cases Base rate moratorium period Public Utilities, Base Rate Moratorium Period Public Utilities, Base Rate Moratorium Period Return on equity refund KCCMergerROERefund Percentage of earned return on equity in excess of authorized return on equity that may be required to be returned to Kansas retail electric customers per the non-unanimous settlement agreement reached with the staff of The State Corporation Commission of the State of Kansas. Charitable contributions period Charitable Contributions Period Charitable Contributions Period Merger transaction costs, recovery amount Merger Transaction Costs, Recovery Amount Merger Transaction Costs, Recovery Amount Merger transaction costs, recovery period Merger Transaction Costs, Recovery Period Merger Transaction Costs, Recovery Period One-time bill credits, period Public Utilities, Estimated One-Time Bill Credits, Period Public Utilities, Estimated One-Time Bill Credits, Period Support to promote low-income weatherization, amount Support To Promote Low-Income Weatherization Efforts, Amount Support To Promote Low-Income Weatherization Efforts, Amount Support to promote low-income weatherization, period Support To Promote Low-Income Weatherization Efforts, Period Support To Promote Low-Income Weatherization Efforts, Period Revenue of acquiree since acquisition Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual Merger-related costs Business Combination, Acquisition Related Costs Related Party Transactions [Abstract] Related Party Transactions and Relationships Related Party Transactions Disclosure [Text Block] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves [Domain] Valuation Allowances and Reserves [Domain] Allowance for Doubtful Accounts [Member] Allowance for Doubtful Accounts [Member] Impairment losses recognized on receivables Valuation Allowances and Reserves, Additions for Charges to Cost and Expense Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Table] Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Table] Decommissioning Trust Assets - Equity [Member] Decommissioning Trust Assets - Equity [Member] Decommissioning Trust Assets - Equity [Member] Decommissioning Trust Assets - Debt [Member] Decommissioning Trust Assets - Debt [Member] Decommissioning Trust Assets - Debt [Member] Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items] Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items] Unrealized gain (losses) Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Dividends Payable [Table] Dividends Payable [Table] Dividends Payable [Line Items] Dividends Payable [Line Items] Dividends Payable Dividends Payable Geographic Distribution, Foreign [Member] Geographic Distribution, Foreign [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] High-Yield Bond Fund [Member] High-Yield Bond Fund [Member] High-Yield Bond Fund [Member] Emerging Markets Bond Fund [Member] Emerging Markets Bond Fund [Member] Emerging Markets Bond Fund [Member] Debt Securities [Member] Debt Securities [Member] US Treasury and Government [Member] US Treasury and Government [Member] US Government Corporations and Agencies Securities [Member] US Government Corporations and Agencies Securities [Member] US States and Political Subdivisions Debt Securities [Member] US States and Political Subdivisions Debt Securities [Member] Corporate Debt Securities [Member] Corporate Debt Securities [Member] Foreign Government Debt Securities [Member] Foreign Government Debt Securities [Member] Cash Equivalents [Member] Cash Equivalents [Member] Cash and Cash Equivalents [Member] Cash and Cash Equivalents [Member] Other Trust Assets [Member] Other Trust Assets [Member] Other assets within the trust fund. Self-Insured Health Plan Trust [Member] Self-Insured Health Plan Trust [Member] Self-Insured Health Plan Trust [Member] Assets [Abstract] Assets, Fair Value Disclosure [Abstract] Total nuclear decommissioning trust Decommissioning Fund Investments, Fair Value Total rabbi trust Rabbi Trust, Fair Value Disclosure Rabbi Trust, Fair Value Disclosure Total self-insured health plan trust Self Insured Health Plan Trust Fair Value Disclosure The fair value of investments held in a trust for KCP&L's self-insurance health plan. Total Assets, Fair Value Disclosure NAV Cash and Cash Equivalents, Fair Value Disclosure Cash and Cash Equivalents, Fair Value Disclosure Level 2 transferred to Level 1 Fair Value, Assets, Level 2 to Level 1 Transfers, Amount Level 2 transferred to NAV Fair Value, Assets, Level 2 To Alternative Investments Transfers, Amount Fair Value, Assets, Level 2 To Alternative Investments Transfers, Amount Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Iatan No 1 And 2 [Member] Jointly Owned Electricity Generation Plant Iatan No 1 And 2 [Member] Jointly Owned Electricity Generation Plant Iatan No 1 And 2 [Member] La Cygne Station [Member] La Cygne Station [Member] La Cygne Station [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Operating Expenses and Capital Costs Billed [Member] Operating Expenses And Capital Costs Billed [Member] Operating Expenses and Capital Costs Billed [Member] Money Pool [Member] Money Pool [Member] Transactions related to the Great Plains Energy Money Pool, an internal financing arrangement between Great Plains Energy, KCP&L and GMO. Income Taxes Payable [Member] Income Taxes Payable [Member] Income Taxes Payable [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Related party transaction Related Party Transaction, Amounts of Transaction Due from (to) related parties Related Party Transaction, Due from (to) Related Party, Current Due to related parties Due to Related Parties, Current Schedule of Short-term Debt [Table Text Block] Schedule of Short-term Debt [Table Text Block] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Senior Notes [Member] Senior Notes [Member] Unsecured Debt [Member] Unsecured Debt [Member] Senior Notes Due 2021 [Member] Senior Notes Due 2021 [Member] Senior Notes Due 2021. Senior Notes 5.292 Percent Series Due 2022 [Member] Senior Notes 5.292 Percent Series Due 2022 [Member] Senior Notes 5.292 Percent Series Due 2022. Senior Notes Due 2048 KCPL [Member] Senior Notes Due 2048 KCPL [Member] Senior Notes Due 2048 KCPL [Member] Senior notes due 2018 KCPL [Member] Senior notes due 2018 KCPL [Member] Senior notes due 2018 KCPL. EIRR bonds 2.875 percent Series 2008 [Member] Eirr Bonds 2875 Percent Series 2008 [Member] 2.875 percent EIRR bonds due 2038. Senior Notes Series A & B [Member] Senior Notes Series A & B [Member] Senior Notes Series A & B [Member] Senior Notes Series A due 2025 [Member] Senior Notes Series A due 2025 [Member] Senior Notes Series A due 2025 Senior Notes Series B due 2033 [Member] Senior Notes Series B due 2033 [Member] Senior Notes Series B due 2033. Debt Instrument [Line Items] Debt Instrument [Line Items] Long-term debt Long-term Debt Fair value adjustment Debt face amount Debt Instrument, Face Amount Long-term debt gross Long-term Debt, Gross Interest rates (in hundredths) Debt Instrument, Interest Rate, Stated Percentage Maturity date Debt Instrument, Maturity Date Repayments of long-term debt Repayments of Debt Repurchased amount Debt Instrument, Repurchase Amount Long-term debt, including current maturities, of KCP&L, GMO and assumed GPE long-term debt LongTermDebtIncrementalDebtFromKCPLGMOAndGPE Amount of long-term debt, including current maturities, of long-term debt of KCP&L, GMO and assumed long-term debt of Great Plains Energy included on Evergy's balance sheet as of the current period. Also includes long-term debt fair value adjustments associated with purchase accounting. Equity Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Schedule of related party receivables and payables Schedule of related party receivables and payables [Table Text Block] Tabular disclosure of related party receivables and payables. Income Earnings Per Share Reconciliation [Abstract] Less: net income allocated to RSUs Dilutive Securities, Effect on Basic Earnings Per Share, Options and Restrictive Stock Units Net income allocated to common stock Net Income (Loss) Available to Common Stockholders, Diluted Common Shares Outstanding Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Weighted average equivalent common shares outstanding - basic (in shares) Add: effect of dilutive securities (in shares) Weighted Average Number Diluted Shares Outstanding Adjustment Weighted average equivalent common shares outstanding - diluted (in shares) Basic and Diluted EPS Earnings Per Share [Abstract] Basic and Diluted EPS (in dollars per share) Earnings Per Share, Basic and Diluted Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Tax Reform [Abstract] Tax Reform [Abstract] Regulatory Liability [Axis] Regulatory Liability [Axis] Regulatory Liability [Domain] Regulatory Liability [Domain] Revenue Subject to Refund [Member] Revenue Subject to Refund [Member] Tax Reform Decrease in net deferred income tax liabilities due to tax reform Increase Decrease In Net Deferred Income Tax Liabilities Due to Tax Reform Increase/Decrease In Net Deferred Income Tax Liabilities Due to Tax Reform Decrease in net deferred income tax liabilities for revaluation of deferred income tax assets and liabilities in rate base Increase Decrease In Net Deferred Income Tax Liabilities For Revaluation Of Regulated Deferred Income Tax Assets And Liabilities Increase (decrease) in net deferred income tax liabilities for revaluation of regulated deferred income tax assets and liabilities Decrease in net deferred income tax liabilities for tax gross-up adjustment for ratemaking purposes due to tax reform Increase (Decrease) in Net Deferred Income Tax Liabilities For Tax Gross-Up Adjustment For Ratemaking Purposes Due To Tax Reform Increase (decrease) in net deferred income tax liabilities for tax gross-up adjustment for ratemaking purposes due to tax reform Income tax benefit from tax reform Income Tax Expense From Tax Reform, Total Income Tax Expense From Tax Reform, Total Schedule of Pre-tax Costs and Deferrals and Purchase Price Allocation Schedule of Business Acquisitions, by Acquisition [Table Text Block] Schedule of Assets Acquired and Liabilities Assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Unaudited Pro Forma Financial Information Business Acquisition, Pro Forma Information [Table Text Block] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Components of Income Tax Expense (Benefit), Continuing Operations [Abstract] Components of Income Tax Expense (Benefit), Continuing Operations [Abstract] Current income taxes Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) State Current State and Local Tax Expense (Benefit) Total Current Income Tax Expense (Benefit) Deferred income taxes Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) State Deferred State and Local Income Tax Expense (Benefit) Total Investment tax credit amortization Income tax expense Effective Income Tax Rate Reconciliation, Percent [Abstract] Effective Income Tax Rate Reconciliation, Percent [Abstract] Federal statutory income tax (in hundredths) Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent COLI policies Effective Income Tax Rate Reconciliation, Nondeductible Expense, Life Insurance, Percent State income taxes Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Flow through depreciation for plant-related differences EffectiveIncomeTaxRateReconciliationEffectOfRegulatoryTreatmentBookTaxDifferences Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to the effect of regulatory treatment of book and tax differences. Effective Income Tax Rate Reconciliation, Nondeductible Expense, Depreciation, Percent Federal tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent Non-controlling interest Effective Income Tax Rate Reconciliation, Noncontrolling Interest Income (Loss), Percent AFUDC Equity EffectiveIncomeTaxRateReconciliationAFUDCEquity Effective Income Tax Rate Reconciliation, AFUDC Equity Amortization of federal investment tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Percent Changes In Uncertain Tax Positions, Net Changes In Uncertain Tax Positions, Net Changes in uncertain tax positions, net State tax rate change Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent Stock compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Percent Officer compensation limitation Officer Compensation Limitation Officer compensation limitation Other Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Effective income tax rate (in hundredths) Effective Income Tax Rate Reconciliation, Percent Guarantees Guarantees [Text Block]