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 Revenues 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 SPPNetworkTransmissionCosts Cost incurred for SPP transmission costs 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 (Loss) Attributable to Parent 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 Weighted Average Number of Shares Outstanding, Basic 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] Net income OTHER COMPREHENSIVE INCOME: Other Comprehensive Income (Loss), Net of Tax [Abstract] Derivative hedging activity Derivative Hedging Activity [Abstract] Derivative Hedging Activity [Abstract] Gain (loss) on derivative hedging instruments Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Income tax benefit (expense) on derivative hedging instruments Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax Net gain (loss) on derivative hedging instruments Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax 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 Defined benefit pension plans Defined Benefit Pension Plans [Abstract] Defined Benefit Pension Plans [Abstract] Net gain (loss) arising during period Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax Income tax benefit benefit (expense) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax Net gain (loss) arising during period, net of tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax Change in unrecognized pension expense, net of tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Total other comprehensive income Other Comprehensive Income (Loss), Net of Tax Total comprehensive income, net of tax, including portion attributable to noncontrolling interest Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Total comprehensive income, net of tax, attributable to noncontrolling interest Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Retirement Benefits [Abstract] Schedule of Net Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Schedule of Net Funded Status [Table Text Block] Schedule of Net Funded Status [Table Text Block] Schedule of Amounts Recognized in Balance Sheet [Table Text Block] Schedule of Amounts Recognized in Balance Sheet [Table Text Block] Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year [Table Text Block] Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year [Table Text Block] Schedule of Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block] Schedule of Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block] Schedule of Assumptions Used [Table Text Block] Schedule of Assumptions Used [Table Text Block] Schedule of Expected Benefit Payments [Table Text Block] Schedule of Expected Benefit Payments [Table Text Block] Schedule of Plan Assets Target Allocations [Table Text Block] ScheduleOfPlanAssetsTargetAllocations [Table Text Block] Tabular disclosure of the target allocations for pension plans and other employee benefit plans. Schedule of Allocation of Plan Assets [Table Text Block] Schedule of Allocation of Plan Assets [Table Text Block] Schedule of Health Care Cost Trend Rates [Table Text Block] Schedule of Health Care Cost Trend Rates [Table Text Block] Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block] Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block] Schedule of Costs of Retirement Plans [Table Text Block] Schedule of Costs of Retirement Plans [Table Text Block] Regulated Operations [Abstract] 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 Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Public Float Entity Public Float Entity Shell Company Entity Shell Company Entity Emerging Growth Company Entity Emerging Growth Company Entity Ex Transition Period Entity Ex Transition Period Entity Small Business Entity Small Business Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Domain] Public Utilities, Regulatory Proceeding [Domain] Merger Settlement Agreement [Member] Merger Settlement Agreement [Member] Merger Settlement Agreement [Member] Regulatory Agency [Axis] Regulatory Agency [Axis] Regulatory Agency [Domain] Regulatory Agency [Domain] Kansas Corporation Commission [Member] Kansas Corporation Commission [Member] Information related to the State Corporation Commission of the State of Kansas. Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Great Plains Energy [Member] Great Plains Energy [Member] Information on Great Plains Energy. Business Acquisition [Line Items] Business Acquisition [Line Items] Additional bill credits, annual amount Public Utilities, Estimated Additional Bill Credits, Annual Amount Public Utilities, Estimated Additional Bill Credits, Annual Amount 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 Statement of Financial Position (Parenthetical) [Abstract] Statement of Financial Position (Parenthetical) [Abstract] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Series B Preferred Stock [Member] Series B Preferred Stock [Member] Evergy [Member] Evergy [Member] Evergy [Member] Common Stock, Shares Authorized Common Stock, Shares Authorized Common Stock, Shares, Issued Common Stock, Shares, Issued Preferred Stock, Shares Issued Preferred Stock, Shares Issued Preferred Stock, Liquidation Preference, Value Preferred Stock, Liquidation Preference, Value Tax Credit Carryforward Disclosure [Abstract] Tax Credit Carryforward Disclosure [Abstract] Tax Credit Carryforward [Table] Tax Credit Carryforward [Table] Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] General Business Tax Credit Carryforward [Member] General Business Tax Credit Carryforward [Member] Federal Alternative Minimum Tax Credit Carryforward [Member] Federal Alternative Minimum Tax Credit Carryforward [Member] Tax credit carryforwards related to the federal Alternative Minimum Tax State and Local Jurisdiction [Member] State and Local Jurisdiction [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Tax Credit Carryforward [Line Items] Tax Credit Carryforward [Line Items] Tax Credit Carryforward, Amount Tax Credit Carryforward, Amount Amount of tax credit acquired in business combination Amount of tax credit acquired in business combination Amount of tax credit acquired in GMO acquisition Tax Credit Carryforward, Description Tax Credit Carryforward, Description Tax Credit Carryforward, Expiration Date Tax Credit Carryforward, Expiration Date Tax Credit Carryforward, Valuation Allowance Tax Credit Carryforward, Valuation Allowance Tax Credit Carryforwards Originating In 2000 TaxCreditCarryforwardOriginatingIn2000 Tax Credit Carryforward Originating In 2000 Tax Credit Carryforwards Originating In 2001 TaxCreditCarryforwardsOriginatingIn2001 Tax Credit Carryforwards Originating In 2001 Tax Credit Carryforwards Originating In 2002 TaxCreditCarryforwardsOriginatingIn2002 Tax Credit Carryforwards Originating In 2002 Tax Credit Carryforwards Originating In 2003 TaxCreditCarryforwardsOriginatingIn2003 Tax Credit Carryforwards Originating In 2003 Tax Credit Carryforwards Originating In 2004 TaxCreditCarryforwardsOriginatingIn2004 Tax Credit Carryforwards Originating In 2004 Tax Credit Carryforwards Originating In 2005 TaxCreditCarryforwardsOriginatingIn2005 Tax Credit Carryforwards Originating In 2005 Tax Credit Carryforwards Originating In 2006 Tax Credit Carryforwards Originating In 2006 Tax Credit Carryforwards Originating In 2006 Tax Credit Carryforwards Originating In 2007 TaxCreditCarryforwardsOriginatingIn2007 Tax Credit Carryforwards Originating In 2007 Tax Credit Carryforwards Originating In 2008 TaxCreditCarryforwardsOriginatingIn2008 Tax Credit Carryforwards Originating In 2008 Tax Credit Carryforwards Originating In 2009 TaxCreditCarryforwardsOriginatingIn2009 Tax Credit Carryforwards Originating In 2009 Tax Credit Carryforwards Originating In 2010 TaxCreditCarryforwardsOriginatingIn2010 Tax Credit Carryforwards Originating In 2010 Tax Credit Carryforwards Originating In 2011 TaxCreditCarryforwardsOriginatingIn2011 Tax Credit Carryforwards Originating In 2011 Tax Credit Carryforwards Originating In 2012 TaxCreditCarryforwardsOriginatingIn2012 Tax Credit Carryforwards Originating In 2012 Tax Credit Carryforwards Originating In 2013 TaxCreditCarryforwardsOriginatingIn2013 Tax Credit Carryforwards Originating In 2013 Tax Credit Carryforwards Originating In 2014 TaxCreditCarryforwardsOriginatingIn2014 Tax Credit Carryforwards Originating In 2014 Tax Credit Carryforwards Originating In 2015 TaxCreditCarryforwardsOriginatingIn2015 Tax Credit Carryforwards Originating In 2015 Tax Credit Carryforwards Originating In 2016 TaxCreditCarryforwardsOriginatingIn2016 Tax Credit Carryforwards Originating In 2016 Tax Credit Carryforwards Originating In 2017 TaxCreditCarryforwardsOriginatingIn2017 Tax Credit Carryforwards Originating In 2017 Tax Credit Carryforwards Originating In 2018 TaxCreditCarryforwardsOriginatingIn2018 Tax Credit Carryforwards Originating In 2018 Summary of Reclassifications [Abstract] Summary of Reclassifications [Abstract] Inventory, Current [Table] Inventory, Current [Table] Inventory [Axis] Inventory [Axis] Inventory [Domain] Inventory [Domain] 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 Receivables [Abstract] 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. Asset Retirement Obligation Disclosure [Abstract] Schedule of Change in Asset Retirement Obligation Schedule of Change in Asset Retirement Obligation [Table Text Block] Deferred Income Taxes Disclosure [Abstract] Deferred Income Taxes Disclosure [Abstract] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Components of Deferred Tax Assets and Liabilities [Abstract] Components of Deferred Tax Assets and Liabilities [Abstract] Deferred Tax Assets, Gross [Abstract] Deferred Tax Assets, Gross [Abstract] Tax credit carryforward Deferred Tax Assets, Tax Credit Carryforwards, General Business Income taxes refundable to customers, net Deferred Tax Assets, Regulatory Assets and Liabilities Deferred employee benefit costs Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation Net operating loss carryforward Deferred Tax Assets, Operating Loss Carryforwards, Domestic Deferred state income taxes Deferred Tax Assets, State Taxes Alternative minimum tax carryforward Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax Accrued liabilities Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Other Deferred Tax Assets, Other Total deferred tax assets before valuation allowance Deferred Tax Assets, Gross Valuation allowances Deferred Tax Assets, Valuation Allowance Total deferred tax assets, net Deferred Tax Assets, Net of Valuation Allowance Deferred Tax Liabilities, Gross [Abstract] Deferred Tax Liabilities, Gross [Abstract] Plant-related Deferred Tax Liabilities, Property, Plant and Equipment Deferred employee benefit costs DeferredTaxLiabilitiesEmployeeBenefitCosts Deferred Tax Liabilities Employee Benefit Costs Acquisition premium DeferredTaxLiabilitiesAcquisitionPremium Deferred Tax Liabilities Acquisition Premium Other Deferred Tax Liabilities, Other Total deferred tax liabilities Deferred Tax Liabilities, Gross Net deferred income tax liabilities Deferred Tax Liabilities, Net SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] SEC Schedule, 12-09, Allowance, Credit Loss [Member] SEC Schedule, 12-09, Allowance, Credit Loss [Member] SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] Balance at beginning of period SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount Additions charged to costs and expenses SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Cost and Expense Additions charged to other accounts SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Other Account Deductions SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction Balance at end of period Pension Plans Fair Value Disclosure [Abstract] Pension Plans Fair Value Disclosure [Abstract] 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 Plan [Member] Pension Plan [Member] Other Postretirement Benefits Plan [Member] Other Postretirement Benefits Plan [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value Measured at Net Asset Value Per Share [Member] Fair Value Measured at Net Asset Value Per Share [Member] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] Domestic equities [Member] Defined Benefit Plan, Equity Securities, US [Member] International equity [Member] Defined Benefit Plan, Equity Securities, Non-US [Member] Corporate bonds [Member] Corporate Debt Securities [Member] US Treasury and agency bonds [Member] US Treasury and Government [Member] Mortgage & asset-backed securities [Member] Asset-backed Securities [Member] Real estate investments [Member] Defined Benefit Plan, Real Estate [Member] Combination debt/equity/other fund [Member] Balanced Funds [Member] Alternative investment funds [Member] Alternative Investment Funds [Member] Alternative Investment Funds [Member] Short-term investments [Member] Short-term Investments [Member] Other [Member] DefinedBenefitPlanOther [Member] Defined Benefit Plan Other [Member] Cash and Cash Equivalents [Member] Cash and Cash Equivalents [Member] Bond funds [Member] Fixed Income Funds [Member] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Traded Mutual Funds [Member] Traded Mutual Funds [Member] This category is comprised of traded mutual funds that are valued at daily listed prices. Institutional Common Collective Trust Funds [Member] Institutional Common Collective Trust Funds [Member] This category is used for institutional common/collective trust funds valued at daily Net Asset Values per share. Common Stock and Exchange Traded Funds [Member] Common Stock and Exchange Traded Funds [Member] Investments in traded common stocks or investments that follow an index, commodity or basket of assets that trades similar to a stock on an exchange. American Depository Receipts Global Depository Receipts and Ordinary Shares [Member] AmericanDepositoryReceiptsGlobalDepositoryReceiptsAndOrdinaryShares [Member] Investments in foreign companies held in traded American Depository Receipts, Global Depository Receipts, and/or ordinary shares of stock. Real Estate Investment Trust [Member] Real Estate Investment Trust [Member] Investments in traded Real Estate Investment Trusts. Limited Partnerships [Member] Limited Partnerships [Member] Investments in limited partnerships. Equity Funds [Member] Equity Funds [Member] Corporate Bonds [Member] Corporate Bond Securities [Member] Collateralized Mortgage Obligation Securities [Member] Collateralized Mortgage Backed Securities [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Fair Value, Assets, Level 2 to Level 1 Transfers, Amount Fair Value, Assets, Level 2 to Level 1 Transfers, Amount Fair Value of Plan Assets Defined Benefit Plan, Plan Assets, Amount Contributions by employer, remainder of fiscal year Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year Fair value of plan assets, beginning of the year Alternative Investment Alternative Investment Fair value measurement with unobservable inputs [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Actual return on plan assets [Abstract] Actual return on plan assets [Abstract] Balance at beginning of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Relating to assets still held Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Actual Return (Loss) on Plan Assets Still Held Relating to assets sold Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Actual Return (Loss) on Plan Assets Sold Purchase, sales and settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, (Sales), Issuances, (Settlements) Balance at end of period Fair Value, Assets, Level 2 To Alternative Investments Transfers, Amount Fair Value, Assets, Level 2 To Alternative Investments Transfers, Amount Fair Value, Assets, Level 2 To Alternative Investments Transfers, Amount Regulatory Assets [Abstract] Regulatory Assets [Abstract] Schedule of Regulatory Assets [Table] Schedule of Regulatory Assets [Table] KCPL Greater Missouri Operations [Member] Kcpl Greater Missouri Operations Member Information on KCPL Greater Missouri Operations. Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] La Cygne Station [Member] La Cygne Station [Member] La Cygne Station [Member] Regulatory Asset [Axis] Regulatory Asset [Axis] Regulatory Asset [Domain] Regulatory Asset [Domain] Pension and post-retirement costs [Member] Pension and Other Postretirement Plans Costs [Member] Loss on reacquired debt [Member] Loss on Reacquired Debt [Member] Debt fair value adjustment [Member] Debt Fair Value Adjustment [Member] Discloses the amount of debt fair value purchase accounting adjustment regulatory assets arising from the merger. Asset retirement obligations fair value adjustment [Member] Asset Retirement Obligations Fair Value Adjustment [Member] Discloses the amount of asset retirement obligation fair value purchase accounting adjustments to related regulatory assets arising from the merger. Depreciation [Member] Depreciation [Member] Discloses the difference between regulatory depreciation and depreciation expense recorded for financial reporting purposes. Removal Costs [Member] Removal Costs [Member] Asset Retirement Obligation Costs [Member] Asset Retirement Obligation Costs [Member] Analog meter unvrecovered investment [Member] Analog Meter Unvrecovered Investment [Member] Discloses the deferral of unrecovered investment of retired analog meters. Treasury Yield Hedge [Member] Treasury Yield Hedge [Member] Treasury Yield Hedge [Member] Cash Flow Hedging [Member] Cash Flow Hedging [Member] Iatan No. 1 and Common facilities depreciation and carrying costs [Member] Iatan No1 And Common Facilities Depreciation And Carrying Costs [Member] Discloses the amount of regulatory asset arising from Iatan No. 1 and common facilities depreciation and carrying costs not included in rate base. Iatan No. 2 construction accounting costs [Member] Iatan No2 Construction Accounting Costs [Member] Discloses the amount of regulatory asset arising from Iatan No. 2 operating costs, depreciation expense and carrying costs offset by Iatan No. 2's system energy value not included in rate base. Kansas property tax surcharge [Member] Kansas Property Tax Surcharge [Member] Discloses the amount of regulatory asset arising from the Kansas property tax surcharge not included in rate base and amortized over various periods. Disallowed plant costs [Member] Disallowed Plant Costs [Member] Discloses certain costs related to the Wolf Creek plant that were originally disallowed by The KCC. LaCygne environmental costs [Member] LaCygne Deferred Depreciation [Member] Discloses the amount of regulatory asset arising from LaCygne depreciation not included in rate base. Deferred customer programs [Member] Deferred Customer Programs [Member] Discloses the amount of regulatory asset arising from deferred customer program. Fuel recovery mechanisms [Member] Deferred Fuel Costs [Member] Solar Rebates [Member] Renewable Energy Program [Member] Transmission Delivery Charge [Member] Transmission Delivery Charge [Member] Transmission Delivery Charge [Member] Wolf Creek outage [Member] Wolf Creek outage [Member] Discloses deferred expenses associated with Wolf Creek's scheduled refueling and maintenance outages. Pension and other post-retirement benefit non-service costs [Member] Pension And Other Post-retirement Benefit Non-service Costs [Member] Discloses the non-service component of pension and post-retirement net benefit costs that are capitalized as authorized by regulators. Retired Generation Facility [Member] Retired Generation Facility [Member] Discloses amounts to be recovered for facilities that have been retired and are probable of recovery. Merger transition costs [Member] Merger Transition Costs [Member] Discloses recoverable transition costs related to the merger. Other Regulatory Assets (Liabilities) [Member] Other Regulatory Assets (Liabilities) [Member] Taxes recoverable through future rates [Member] Deferred Income Tax Charge [Member] Rate case expenses [Member] Rate Case Expenses [Member] Expenses, associated with various rate cases, which are deferred as regulatory assets based on the expected ability to recover them in future rates. This amount is not included in rate base and amortized over various periods. Derivative instruments [Member] Deferred Derivative Gain (Loss) [Member] Voluntary Separation Program [Member] Voluntary Separation Program [Member] Regulatory asset arising from costs related to the voluntary separation program. Missouri Public Service Division [Member] Missouri Public Service Division [Member] Information related to Missouri Public Service, a division of GMO. Regulatory Assets [Line Items] Regulatory Assets [Line Items] Regulatory Assets Regulatory Assets Regulatory Assets, Current Regulatory Assets, Current Regulatory Assets, Noncurrent Regulatory Assets, Noncurrent Amount not included in rate base Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided Regulatory Noncurrent Asset, End Date for Recovery Regulatory Noncurrent Asset, End Date for Recovery Regulatory Asset, Amortization Period Regulatory Asset, Amortization Period Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Jointly Owned Electric Utility Plants [Abstract] Jointly Owned Utility Plant Interests [Table] Jointly Owned Utility Plant Interests [Table] La Cygne Unit 2 [Member] La Cygne Unit 2 [Member] La Cygne Unit 2 [Member] Jeffrey Energy Center [Member] Jeffrey Energy Center [Member] Jeffrey Energy Center [Member] Jointly Owned Utility Plant [Axis] Jointly Owned Utility Plant [Axis] Jointly Owned Utility Plant [Domain] Jointly Owned Utility Plant [Domain] Iatan Common [Member] Jointly Owned Electricity Generation Plant Iatan Common [Member] Information on the jointly owned Iatan Common electric utility plant. Jeffrey Energy Center [Member] Jointly Owned Electricity Generation Plant Jeffrey Energy Center [Member] Information on the jointly owned Jeffrey Energy Center electric utility plant. Iatan No. 2 [Member] Jointly Owned Electricity Generation Plant Iatan No. 2 [Member] Information on the jointly owned Iatan No. 2 electric utility plant. Iatan No. 1 [Member] Jointly Owned Electricity Generation Plant Iatan No 1 [Member] Information on the jointly owned Iatan No. 1 electric utility plant. LaCygne Station [Member] JointlyOwnedElectricityGenerationPlantLaCygneStation [Member] LaCygne Station, a jointly owned plant in connection with generation of electricity, excluding nuclear. Wolf Creek [Member] Jointly Owned Nuclear Power Plant [Member] State Line [Member] Jointly Owned Electricity Generation Plant State Line [Member] State Line, a jointly owned plant in connection with generation of electricity, excluding nuclear. Jointly Owned Utility Plant Interests [Line Items] Jointly Owned Utility Plant Interests [Line Items] Jointly owned utility plant, proportionate ownership share Jointly Owned Utility Plant, Proportionate Ownership Share Utility plant in service Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service Accumulated depreciation Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation Nuclear fuel, net Nuclear Fuel, Net of Amortization Construction work in progress Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress Accredited capacity Accredited Capacity The accredited capacity of the jointly owned electric utility plant, in megawatts. Leasehold Interest Percentage Leasehold Interest Percentage Leasehold Interest Percentage 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 Property, Plant and Equipment [Abstract] 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] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Public Utility Property, Plant, and Equipment [Table Text Block] Public Utility Property, Plant, and Equipment [Table Text Block] Summary of Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Property_Plant_&_Equipment_of_VIEs [Table Text Block] Property_Plant_&_Equipment_of_VIEs [Table Text Block] Property_Plant_&_Equipment_of_VIEs [Table Text Block] Depreciation_Expense [Table Text Block] Depreciation_Expense [Table Text Block] Depreciation_Expense [Table 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] 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] 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] 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. Assets, Fair Value Disclosure Assets, 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 Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Asset Retirement Obligations Asset Retirement Obligation Disclosure [Text Block] Accounting Policies [Abstract] Consolidation, Policy [Policy Text Block] Consolidation, Policy [Policy Text Block] Use of Estimates, Policy [Policy Text Block] Use of Estimates, Policy [Policy Text Block] Cash and Cash Equivalents, Policy [Policy Text Block] Cash and Cash Equivalents, Policy [Policy Text Block] Fuel Inventory and Supplies Inventory, Policy [Policy Text Block] Property, Plant and Equipment, Policy [Policy Text Block] Property, Plant and Equipment, Policy [Policy Text Block] Depreciation, Depletion, and Amortization [Policy Text Block] Depreciation, Depletion, and Amortization [Policy Text Block] Plant Retirement and Abandonment, Policy [Policy Text Block] Plant Retirement and Abandonment, Policy [Policy Text Block] Asset Retirement Obligation [Policy Text Block] Asset Retirement Obligation [Policy Text Block] Public Utilities, Policy [Policy Text Block] Public Utilities, Policy [Policy Text Block] Life Settlement Contracts, Policy [Policy Text Block] Life Settlement Contracts, Policy [Policy Text Block] Fair Value of Financial Instruments, Policy [Policy Text Block] Fair Value of Financial Instruments, Policy [Policy Text Block] Revenue from Contract with Customer [Policy Text Block] Revenue from Contract with Customer [Policy Text Block] Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block] Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block] Property Gains And Losses [Policy Text Block] PropertyGainsAndLosses [Policy Text Block] Property Gains And Losses [Policy Text Block] Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Income Tax, Policy [Policy Text Block] Income Tax, Policy [Policy Text Block] New Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block] Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block] Earnings Per Share, Policy [Policy Text Block] Earnings Per Share, Policy [Policy Text Block] Income Tax Disclosure [Abstract] 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 Deferred Income Tax Expense (Benefit) Investment Tax Credit Investment Tax Credit [Abstract] Investment Tax Credit [Abstract] 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. Total Investment Tax Credit, Total Total investment tax credit included in current tax expense. 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. 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 Federal or 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 Operating Leases [Abstract] Operating Leases [Abstract] Operating Leases, Rent Expense, Net Operating Leases, Rent Expense, Net 2019 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2020 Operating Leases, Future Minimum Payments, Due in Two Years 2021 Operating Leases, Future Minimum Payments, Due in Three Years 2022 Operating Leases, Future Minimum Payments, Due in Four Years 2023 Operating Leases, Future Minimum Payments, Due in Five Years After 2023 Operating Leases, Future Minimum Payments, Due Thereafter Total Operating Leases, Future Minimum Payments Due Stockholders' Equity Note [Abstract] 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] KCP&L Receivables Company [Member] KCP&L Receivables Company [Member] KCP&L Receivables Company [Member] Kcpl Greater Missouri Operations Member Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Master Credit Facility [Member] Revolving Credit Facility [Member] Common Shareholders' Equity [Line Items] Common Shareholders' Equity [Line Items] Common Shareholders' Equity [Line Items] Common stock - shares authorized (in shares) 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 Repurchase of common stock Stock Repurchased During Period, Value Stock Repurchased and Retired During Period, Value 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 Final Settlement Of Accelerated Share Repurchase Agreement Shares FinalSettlementOfAcceleratedShareRepurchaseAgreementShares Final Settlement Of Accelerated Share Repurchase Agreement Shares [Line Items] 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 Debt Instrument, debt to capitalization ratio Debt Instrument, Covenant, Debt to Capitalization Ratio Debt Instrument, Covenant, Debt to Capitalization Ratio 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 Pension Plans and Other Employee Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] 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] Corporate-Owned Life Insurance [Abstract] Corporate-Owned Life Insurance [Abstract] Cash surrender value of policies Cash Surrender Value of Life Insurance Borrowings against policies Corporate Owned Life Insurance Borrowings Corporate Owned Life Insurance Borrowings Corporate-owned life insurance, net Life Insurance, Corporate or Bank Owned, Amount 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 Receivables, Net, Current Related party receivables Accounts Receivable, Related Parties, Current Accounts receivable pledged as collateral Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount Fuel inventory and supplies Income taxes receivable Income Taxes Receivable, Current Regulatory assets 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 Nuclear decommissioning trust fund Decommissioning Fund Investments Goodwill Goodwill Other Other Assets, Noncurrent Total Other Assets Assets, Noncurrent 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 Collateralized note payable Transfers Accounted for as Secured Borrowings, Associated Liabilities, Carrying Amount 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 Asset retirement obligations Asset Retirement Obligation, 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 Liability, Defined Benefit Plan, Noncurrent Asset retirement obligations Asset Retirement Obligations, Noncurrent Other Other Liabilities, Noncurrent Total Long-Term Liabilities Liabilities, Noncurrent Commitments and Contingencies (Note 14) 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 Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest TOTAL LIABILITIES AND EQUITY Liabilities and Equity Net Operating Loss Carryforwards Disclosure [Abstract] Net Operating Loss Carryforwards Disclosure [Abstract] Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Internal Revenue Service (IRS) [Member] Internal Revenue Service (IRS) [Member] Kansas City Power and Light Company [Member] Subsidiaries [Member] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards Operating Loss Carryforwards Amount of Net Operating Losses related to business acquisition Amount of Net Operating Losses related to business acquisition The amount of net operating loss carryforwards acquired in in the GMO acquisition. Operating Loss Carryforwards, Valuation Allowance Operating Loss Carryforwards, Valuation Allowance Operating Loss Carryforwards, Expiration Date Operating Loss Carryforwards, Expiration Date Net operating losses year of origination [Abstract] Net operating losses year of origination [Abstract] Net operating losses year of origination [Abstract] Net operating loss carryforwards originating in 2003 Net operating loss carryforwards originating in 2003 Net operating loss carryfowards originating in 2003 Net operating loss carryfowards originating in 2004 Net operating loss carryfowards originating in 2004 Net operating loss carryfowards originating in 2004 Net operating loss carryfowards originating in 2005 Net operating loss carryfowards originating in 2005 Net operating loss carryfowards originating in 2005 Net operating loss carryfowards originating in 2006 Net operating loss carryfowards originating in 2006 Net operating loss carryfowards originating in 2006 Net operating loss carryfowards originating in 2007 Net operating loss carryfowards originating in 2007 Net operating loss carryfowards originating in 2007 Net operating loss carryfowards originating in 2008 Net operating loss carryfowards originating in 2008 Net operating loss carryfowards originating in 2008 Net operating loss carryfowards originating in 2009 Net operating loss carryfowards originating in 2009 Net operating loss carryfowards originating in 2009 Net operating loss carryfowards originating in 2010 Net operating loss carryfowards originating in 2010 Net operating loss carryfowards originating in 2010 Net operating loss carryfowards originating in 2011 Net operating loss carryfowards originating in 2011 Net operating loss carryfowards originating in 2011 Net operating loss carryforwards originating in 2012 Net Operating Loss Carryforwards Originating In 2012 Net operating loss carryforwards originating in 2012 Net operating loss carryforwards originating in 2013 Net Operating Loss Carryforwards Originating In 2013 Net operating loss carryforwards originating in 2013. Net operating loss carryforwards originating in 2014 Net Operating Loss Carryforwards Originating In 2014 Net operating loss carryforwards originating in 2014 Net operating loss carryforwards originating in 2015 Net Operating Loss Carry Forwards Originating In 2015 Net Operating Loss Carry Forwards Originating in 2015 Net operating loss carryforwards originating in 2016 Net Operating Loss Carryforwards Originating in 2016 Net Operating Loss Carryforwards Originating in 2016 Net operating loss carryforwards originating in 2017 NetOperatingLossCarryforwardsOriginatingin2017 Net Operating Loss Carryforwards Originating in 2017 Net operating loss carryforwards originating in 2018 NetOperatingLossCarryforwardsOriginatingIn2018 Net Operating Loss Carryforwards Originating In 2018 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] Commercial Paper [Member] Commercial Paper [Member] Standby Letters of Credit [Member] Standby Letters of Credit [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 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 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] Allowance for funds used during construction [Table Text Block] ScheduleOfAllowanceForFundsUsedDuringConstruction [Table Text Block] Schedule Of Allowance For Funds Used During Construction [Table Text Block] Depreciable Lives of Property Plant and Equipment [Table Text Block] Depreciable Lives of Property Plant and Equipment [Table Text Block] Depreciable Lives of Property Plant and Equipment [Table Text Block] Cash surrender value of corporate owned life insurance [Table Text Block] CashSurrenderValueOfCorporateOwnedLifeInsurance [Table Text Block] Cash surrender value of corporate owned life insurance [Table Text Block] Other Income (Expense), Net [Table Text Block] Schedule of Other Nonoperating Income (Expense) [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] Short-term Borrowings and Short-term Bank Lines of Credit Short-term Debt [Text Block] 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] Maximum Amount Of Outstanding Principal Under Receivables Agreement From Mid-Dec To Mid-Jan MaximumAmountOfOutstandingPrincipalUnderReceivablesAgreementFromMid-DecToMid-Jan Maximum amount of outstanding principal under receivables agreement from mid-Dec to mid-Jan 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 Jan To Mid Feb MaximumAmountOfOutstandingPrincipalUnderReceivablesAgreementFromJanToMidFeb Maximum Amount Of Outstanding Principal Under Receivables Agreement From Jan To Mid Feb Maximum amount of outstanding principal under receivable agreement from mid-July to expiration MaximumAmountOfOutstandingPrincipalUnderReceivableAgreementFromMid-JulyToExpiration Maximum amount of outstanding principal under receivable agreement from mid-July to the expiration date of the facility. Maximum Amount Of Outstanding Principal Under Receivables Agreement From Mid February to Mid July Maximum Amount Of Outstanding Principal Under Receivables Agreement From Mid February to Mid July Maximum Amount Of Outstanding Principal Under Receivables Agreement From Mid February to mid July. Maximum amount of outstanding principal under receivables agreement from mid-June to expiration MaximumAmountOfOutstandingPrincipalUnderReceivablesAgreementFromMidJunToExpiration Maximum Amount Of Outstanding Principal Under Receivables Agreement From Mid JunTo Expiration Related Party Transactions [Abstract] Related Party Transactions and Relationships Related Party Transactions Disclosure [Text Block] Income Tax Disclosure [Text Block] Income Tax Disclosure [Text Block] Subsequent Events [Abstract] Subsequent Event [Table] Subsequent Event [Table] Transmission Delivery Charge [Member] 2018 Rate Case Proceedings [Member] 2018 Rate Case Proceedings [Member] 2018 Rate Case Proceedings [Member] FERC Proceedings [Member] FERC Proceedings [Member] FERC Proceedings [Member] FERC 2019 TFR Proceeding [Member] FERC2019TFRProceeding [Member] FERC 2019 TFR Proceeding Missouri Public Service Commission [Member] MissouriPublicServiceCommission [Member] Information related to the Public Service Commission of the State of Missouri. Federal Energy Regulatory Commission [Member] Federal Energy Regulatory Commission [Member] Federal Energy Regulatory Commission [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] 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 Valuation Allowance [Abstract] Valuation Allowance [Table] Valuation Allowance [Table] Valuation Allowance by Deferred Tax Asset [Axis] Valuation Allowance by Deferred Tax Asset [Axis] Deferred Tax Asset [Domain] Deferred Tax Asset [Domain] Valuation Allowance [Line Items] Valuation Allowance [Line Items] Valuation Allowance, Deferred Tax Asset, Change in Amount Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Valuation Allowance, Deferred Tax Asset, Explanation of Change Valuation Allowance, Deferred Tax Asset, Explanation of Change Schedule II Valuation and Qualifying Accounts SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] 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] 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. Depreciation Depreciation Electric plant in service Public Utilities, Property, Plant and Equipment, Plant in Service Electric plant acquisition adjustment Property, Plant And Equipment, Adjustment Property, Plant And Equipment, Adjustment Accumulated depreciation Public Utilities, Property, Plant and Equipment, Accumulated Depreciation Plant in service Public Utilities Property Plant And Equipment In Service Net Public Utilities Property Plant And Equipment In Service Net Construction work in progress Public Utilities, Property, Plant and Equipment, Construction Work in Progress Nuclear fuel, net Plant To Be Retired, Net Plant To Be Retired, Net Net value of plant to be retired at period end Property, plant and equipment, net Electric plant in service Electric plant in service Electric plant in service Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Plant in service Plant in service Plant in service Regulatory Proceedings [Table] Public Utilities General Disclosures [Table] 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 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 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, 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 Final amount of one time customer bill credit FinalAmountOfOneTimeCustomerBillCredit Final amount of one time customer bill credit to be paid to customers related to the impact of the Tax Cuts and Jobs Act. 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 Liabilities Regulatory Liabilities Annual transmissions revenue estimated amount of increase (decrease) over prior year Public Utilities, Estimated Annual Transmission Revenue Increase (Decrease) Over Prior Year Amount, Before Tax Rate Change Reduction PublicUtilitiesEstimatedAnnualTransmissionRevenueIncreaseDecreaseOverPriorYearAmountBeforeTaxRateChangeReduction Public Utilities Estimated Annual Transmission Revenue Increase (Decrease) Ove rPrior Year Amount Before Tax Rate Change Reduction Public Utilities, Estimated Annual Transmission Revenue (Increase) Decrease Over Prior Year Amount, Reduction Due To Tax Rate Change PublicUtilitiesEstimatedAnnualTransmissionRevenueIncreaseDecreaseOverPriorYearAmountReductionDueToTaxRateChange Public Utilities Estimated Annual Transmission Revenue Increase (Decrease) Over Prior Year Amount Reduction Due To Tax Rate Change 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. Revenue from Contract with Customer [Abstract] 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] 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. Revenues Depreciable Lives [Abstract] Depreciable Lives [Abstract] Regulatory Asset [Domain] Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service Public Utilities, Property, Plant and Equipment, Generation, Useful Life Public Utilities, Property, Plant and Equipment, Generation, Useful Life Public Utilities, Property, Plant and Equipment, Transmission, Useful Life Public Utilities, Property, Plant and Equipment, Transmission, Useful Life Public Utilities, Property, Plant and Equipment, Distribution, Useful Life Public Utilities, Property, Plant and Equipment, Distribution, Useful Life Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Useful Life Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Useful Life Condensed Financial Information Disclosure [Abstract] Condensed Financial Statements [Table] Condensed Financial Statements [Table] Great Plains Energy [Member] Parent Company [Member] Condensed Financial Information of Parent Company Only Disclosure [Text Block] Condensed Financial Information of Parent Company Only Disclosure [Text Block] 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] 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 Quarterly Financial Information Disclosure [Abstract] Quarterly Financial Information [Text Block] Quarterly Financial Information [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. Merger-related, after tax costs BusinessCombinationMergerRelatedCostsAfterTax Business Combination Merger Related Costs, AfterTax 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 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 Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Restatement [Axis] Restatement [Axis] Restatement [Domain] Restatement [Domain] As Previously Reported [Member] 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] 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 Investment tax credit amortization Net deferred income taxes and credits Deferred Income Taxes and Tax Credits Payments for asset retirement obligations Asset Retirement Obligation, Cash Paid to Settle Other/Solar rebates paid 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 Increase (Decrease) in Interest Payable, Net 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 Total reclassifications 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 Total reclassifications Net Cash Provided by (Used in) Investing Activities Unrecorded Unconditional Purchase Obligation [Table] Unrecorded Unconditional Purchase Obligation [Table] Unrecorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Unrecorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Fuel [Member] Public Utilities, Inventory, Fuel [Member] Power [Member] Purchased Power [Member] Commitments for purchased power. Other [Member] Other purchase commitments [Member] Purchase commitments for other items not otherwise disclosed in the taxonomy. Unrecorded Unconditional Purchase Obligations and Lease Commitments [Line Items] Unrecorded Unconditional Purchase Obligation [Line Items] Purchase Commitments [Abstract] Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract] Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months Unrecorded Unconditional Purchase Obligation, Due within Two Years Unrecorded Unconditional Purchase Obligation, Due within Two Years Unrecorded Unconditional Purchase Obligation, Due within Three Years Unrecorded Unconditional Purchase Obligation, Due within Three Years Unrecorded Unconditional Purchase Obligation, Due within Four Years Unrecorded Unconditional Purchase Obligation, Due within Four Years Unrecorded Unconditional Purchase Obligation, Due within Five Years Unrecorded Unconditional Purchase Obligation, Due within Five Years Unrecorded Unconditional Purchase Obligation, Due after Five Years Unrecorded Unconditional Purchase Obligation, Due after Five Years Unrecorded Unconditional Purchase Obligation Unrecorded Unconditional Purchase Obligation Total operating expenses Equity in earnings from subsidiaries Investment earnings Total other income (expense), net Interest expense INCOME BEFORE INCOME TAXES Income tax (expense) benefit Net income (loss) Income tax benefit Reclassification to expenses Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax Income tax (expense) benefit on reclassification to expenses Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Reclassification to expenses, net of tax Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Other comprehensive income from subsidiaries, net of tax Other comprehensive income from subsidiaries, net of tax Other comprehensive income from subsidiaries, net of tax Total other comprehensive income Comprehensive income 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) Allowance for Funds Used During Construction [Abstract] Allowance for Funds Used During Construction [Abstract] Public Utilities, Allowance for Funds Used During Construction, Rate Public Utilities, Allowance for Funds Used During Construction, Rate AFUDC borrowed funds AFUDC equity funds Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity Total Public Utilities, Allowance for Funds Used During Construction, Additions Other Income (Expense) [Abstract] Other Income (Expense) [Abstract] Non Service Cost Component Of Net Benefit Cost Non Service Cost Component Of Net Benefit Cost Non Service Cost Component Of Net Benefit Cost Other Other Expenses Other expense Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Kansas Gas And Electric Company [Member] Kansas Gas And Electric Company [Member] Kansas Gas And Electric Company [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Secured Debt [Member] Secured Debt [Member] Pollution Control Bonds [Member] Pollution Control Bonds [Member] Pollution Control Bonds [Member] Senior Notes [Member] Senior Notes [Member] Medium-term Notes [Member] Medium-term Notes [Member] Unsecured Debt [Member] Unsecured Debt [Member] Corporate Debt Securities [Member] Mortgage Bonds Due 2020 WR [Member] MortgageBondsDue2020WR [Member] Mortgage Bonds due 2020 WR [Member] Mortgage Bonds Due 2025 WR [Member] MortgageBondsDue2025WR [Member] Mortgage Bonds Due 2025 WR [Member] Mortgage Bonds Due 2026 WR [Member] MortgageBondsDue2026WR [Member] Mortgage Bonds Due 2026 WR [Member] Mortgage Bonds Due 2027 WR [Member] MortgageBondsDue2027WR [Member] Mortgage Bonds Due 2027 WR [Member] Mortgage Bonds Due 2042 WR [Member] MortgageBondsDue2042WR [Member] Mortgage Bonds Due 2042 WR [Member] Mortgage Bonds Due 2043A WR [Member] MortgageBondsDue2043AWR [Member] Mortgage Bonds Due 2043A WR [Member] Mortgage Bonds Due 2043B WR [Member] MortgageBondsDue2043BWR [Member] Mortgage Bonds Due 2043B WR [Member] Mortgage Bonds Due 2045 WR [Member] MortgageBondsDue2045WR [Member] Mortgage Bonds Due 2045 WR [Member] Mortgage Bonds Due 2019 KGE [Member] MortgageBondsDue2019KGE [Member] Mortgage Bonds Due 2019 KGE [Member] Mortgage Bonds Due 2023 KGE [Member] MortgageBondsDue2023KGE [Member] Mortgage Bonds Due 2023 KGE [Member] Mortgage Bonds Due 2037 KGE [Member] MortgageBondsDue2037KGE [Member] Mortgage Bonds Due 2037 KGE [Member] Mortgage Bonds Due 2038 KGE [Member] MortgageBondsDue2038KGE [Member] Mortgage Bonds Due 2038 KGE [Member] Mortgage Bonds Due 2044 KGE [Member] MortgageBondsDue2044KGE [Member] Mortgage Bonds Due 2044 KGE [Member] General Mortgage Bonds EIRR Due 2023 [Member] General Mortgage Bonds EIRR Due 2023 [Member] General Mortgage Bonds EIRR Due 2023 [Member] General Mortgage bonds Series 2009A due 2019 [Member] General Mortgage bonds Series 2009 due 2019 [Member] General Mortgage bonds Series 2009 due 2019. First Mortgage Bonds due through 2021 [Member] First Mortgage Bonds due through 2021 [Member] First Mortgage Bonds due through 2021 [Member] Pollution Control Bonds Due 2032A WR [Member] PollutionControlBondsDue2032AWR [Member] Pollution Control Bonds Due 2032A WR [Member] Pollution Control Bonds Due 2032B WR [Member] PollutionControlBondsDue2032BWR [Member] Pollution Control Bonds Due 2032B WR [Member] Pollution Control Bonds Due 2027 KGE [Member] PollutionControlBondsDue2027KGE [Member] Pollution Control Bonds Due 2027 KGE [Member] Pollution Control Bonds Due 2031 KGE [Member] PollutionControlBondsDue2031KGE [Member] Pollution Control Bonds Due 2031 KGE [Member] Pollution Control Bonds Due 2032A KGE [Member] PollutionControlBondsDue2032AKGE [Member] Pollution Control Bonds Due 2032A KGE [Member] Pollution Control Bonds Due 2032B KGE [Member] PollutionControlBondsDue2032BKGE [Member] Pollution Control Bonds Due 2032B KGE [Member] EIRR Bonds Series 2007A and 2007B due 2035 [Member] EIRR Bonds Series 2007A and 2007B due 2035 [Member] EIRR Bonds Series 2007A and 2007B due 2035 [Member] EIRR bonds 2.875 percent Series 2008 [Member] Eirr Bonds 2875 Percent Series 2008 [Member] 2.875 percent EIRR bonds due 2038. Senior notes due 2018 KCPL [Member] Senior notes due 2018 KCPL [Member] Senior notes due 2018 KCPL. Senior Notes due 2023 KCPL [Member] Senior Notes due 2023 KCPL [Member] 3.15% Series Senior Notes due 2023 KCPL [Member] Senior Notes due 2025 KCPL [Member] Senior Notes due 2025 KCPL [Member] Senior Notes due 2025 KCPL [Member] Senior notes due 2035 KCPL [Member] Senior notes due 2035 KCPL [Member] Senior notes due 2035 KCPL. Senior Notes Due 2041 KCPL [Member] Senior Notes Due 2041 KCPL [Member] Senior Notes Due 2041 KCPL. Senior Notes Due 2047 KCPL [Member] Senior Notes Due 2047 KCPL [Member] Senior Notes Due 2047. Senior Notes Due 2048 KCPL [Member] Senior Notes Due 2048 KCPL [Member] Senior Notes Due 2048 KCPL [Member] Senior notes 8.27 percent series due 2021 [Member] Senior Notes 827 Percent Series Due 2021 [Member] Senior notes 8.27 percent series due 2021. 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. Senior Notes Series C due 2043 [Member] Senior Notes Series C due 2043 [Member] Senior Notes Series C due 2043. 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. Medium term notes 7.33 percent series due 2023 [Member] Medium Term Notes 733 Percent Series Due 2023 [Member] Medium term notes 7.33 percent series due 2023. Medium term notes 7.17 percent series due 2023 [Member] Medium Term Notes 717 Percent Series Due 2023 [Member] Medium term notes 7.17 percent series due 2023 General Mortgage bonds EIRR series 2007B due 2035 [Member] General Mortgage bonds EIRR series 2007B due 2035 [Member] General Mortgage bonds EIRR series 2007B due 2035. Unsecured Debt Due 2021 VIE [Member] UnsecuredDebtDue2021VIE [Member] Unsecured Debt Due 2021 VIE [Member] General Mortgage bonds EIRR series 2005 [Member] General Mortgage bonds EIRR series 2005 [Member] General Mortgage bonds EIRR series 2005 Long-Term debt fair value adjustment [Member] Long-TermDebtFairValueAdjustment [Member] Long-Term debt fair value adjustment recorded in association with the merger. Debt Instrument [Line Items] Debt Instrument [Line Items] Total Redemption Cost, Amount Extinguishment of Debt, Amount Long-term debt gross Long-term Debt, Gross EIRR bonds repurchased and held Debt Instrument Carrying Amount Repurchased and Held Amount of long-term debt before deduction of unamortized discount or premium that has been repurchased and is being held by the issuer. Maturity date Debt Instrument, Maturity Date Debt Instrument Maturity Date Range Start Debt Instrument, Maturity Date Range, Start Debt Instrument Maturity Date Range End Debt Instrument, Maturity Date Range, End Current maturities Unamortized discount and premium, net and debt issuance costs Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Interest rates (in hundredths) Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed Long-term Debt, Weighted Average Interest Rate, at Point in Time Long-term Debt, Weighted Average Interest Rate, at Point in Time Variable rate (in hundredths) Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate Rate after amortizing gains or losses in Other Comprehensive Income (in hundredths) Debt Instrument, Interest Rate, Effective Percentage Amortization of Financing Costs Amortization of Debt Issuance Costs Line Of Credit Facility Maximum Borrowing Capacity As Amended Line Of Credit Facility Maximum Borrowing Capacity As Amended Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility, as amended. Debt Instrument, Optional Redemption Price, Percentage Debt Instrument, Optional Redemption Price, Percentage The redemption price of the aggregate principle amount of Great Plains Energy's $4.3 billion senior notes if at any time prior to November 30, 2017, Great Plains Energy determines in its reasonable judgment that the anticipated acquisition of Westar will not close prior to November 30, 2017. Debt Instrument, Mandatory Redemption Price, Percentage Debt Instrument, Mandatory Redemption Price, Percentage The redemption price of the aggregate principle amount of Great Plains Energy's $4.3 billion senior notes in the event that the anticipated acquisition of Westar does not close by November 30, 2017, or in the event that the Merger Agreement is earlier terminated. Repayments of long-term debt Repayments of Debt Proceeds from Issuance of Senior Long-Term Debt Proceeds from Issuance of Debt Total Redemption Cost Total Long-Term Debt Redemption Cost Total redemption cost of long-term debt consisting of the principal amount of the senior notes plus a redemption premium, and including accrued and unpaid interest Loss on extinguishment of debt Gain (Loss) on Extinguishment of Debt Fair value adjustment Business Acquisition, Fair Value Adjustment, Long-Term Debt Business Acquisition, Fair Value Adjustment, Long-Term Debt Debt Instrument, Face Amount Debt Instrument, Face Amount Debt Instrument, Repurchase 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. KCPL Municipal Bond Insurance Policies [Abstract] KCPL Municipal Bond Insurance Policies [Abstract] KCPL Municipal Bond Insurance Policies [Abstract] Insurance Agreement Covenant Indebtedness To Total Capitalization Ratio Maximum Insurance Agreement Covenant Indebtedness To Total Capitalization Ratio Maximum The maximum indebtedness to total capitalization ratio permitted under the municipal bond insurance policy. Principal outstanding covered by insurance policies Principal outstanding covered by insurance policies Principal value of debt instrument outstanding which is covered by a municipal bond insurance policy between KCP and L and Syncora Guarantee, Inc. (Syncora). The insurance agreements beotween KCP and L and Syncora provide for reimbursement by KCP and L for any amounts that Syncora pays under the municipal bond insurance policies. Additional collateral necessary due to issuance of additional mortgage bonds Additional collateral necessary due to issuance of additional mortgage bonds Additional collateral necessary under the insurance agreement due to the issuance of general mortgage bonds in 2009 that resulted in the aggregate amount of outstanding general mortgage bonds exceeding 10% of total capitalization. Insurance Agreement Covenant Description Insurance Agreement Covenant Description Description of minimum financial levels (for example, tangible net worth and working capital) and achievement of certain financial ratios (for example, working capital ratio and debt service coverage ratio), and adherence to certain clauses which generally require or restrict certain actions (for example, entering into a debt arrangement with equal or greater seniority, and selling or discontinuing a certain business segment or material subsidiary) to be in compliance with the covenant clauses of the municipal bond insurance policy. May also include a discussion of the adverse consequences that would result if the entity violates or fails to satisfy the covenants. Insurance Agreement Covenant Compliance Insurance Agreement Covenant Compliance States whether the entity was in compliance with the municipal bond insurance covenants throughout the reporting period, and describes facts and circumstances of any compliance failure. Proportion Of Secured Debt To Total Indebtedness Based On Bond Ratings Maximum In Hundredths Proportion Of Secured Debt To Total Indebtedness Based On Bond Ratings Maximum In Hundredths The maximum proportion of secured debt to total capitalization under which KCP and L may issue additional bonds per its General Mortgage Indenture, if the long-term rating for such bonds by Standard and Poor's or Moody's Investors Service would be at or below A- or A3. If this ratio of secured debt to total capitalization would exceed this amount after giving effect to such additional bonds, no additional bonds may be issued. Aggregate Amount Of Outstanding General Mortgage Bonds As Percentage Of Total Capitalization Maximum In Hundredths Aggregate Amount Of Outstanding General Mortgage Bonds As Percentage Of Total Capitalization Maximum In Hundredths If the aggregate amount of outstanding general mortgage bonds as a percentage of total capitalization exceeds this amount, additional collateral must be provided to the insurance company under the municipal bonds insurance agreement. Long-term Debt, Fiscal Year Maturity [Abstract] Long-term Debt, Fiscal Year Maturity [Abstract] Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months Long-term Debt, Maturities, Repayments of Principal in Year Two Long-term Debt, Maturities, Repayments of Principal in Year Two Long-term Debt, Maturities, Repayments of Principal in Year Three Long-term Debt, Maturities, Repayments of Principal in Year Three Long-term Debt, Maturities, Repayments of Principal in Year Four Long-term Debt, Maturities, Repayments of Principal in Year Four Long-term Debt, Maturities, Repayments of Principal in Year Five Long-term Debt, Maturities, Repayments of Principal in Year Five GMO Senior Notes [Abstract] GMO Senior Notes [Abstract] GMO Senior Notes Debt Instrument, Covenant Description Debt Instrument, Covenant Description Debt Instrument, Covenant Compliance Debt Instrument, Covenant Compliance Westar Mortgage Bonds [Abstract] WestarMortgageBonds [Abstract] Westar Mortgage Bonds [Abstract] Debt Instrument, Restrictive Covenants Debt Instrument, Restrictive Covenants Additional Principal First Mortgage Bonds Available To Be Issued AdditionalPrincipalFirstMortgageBondsAvailableToBeIssued Principal amount of additional first mortgage bonds available to be issued under th most restrictive mortgage provisions. Maximum Amount Of First Mortgage Bonds Authorized MaximumAmountOfFirstMortgageBondsAuthorized The maximum amount of First Mortgage Bonds authorized to be issued under the mortgage and deed of trust. Statement of Cash Flows [Abstract] Cash and cash equivalents CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] 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 refueling outage 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 Gain (Loss) on Sale of Properties Gain (Loss) on Sale of Properties Non-cash compensation Share-based Compensation Allowance for equity funds used during construction Increase (Decrease) in Allowance for Equity Funds Used During Construction Payments for asset retirement obligations Payments For Asset Retirement Obligations Payments For Asset Retirement Obligations Equity in earnings of equity method investees, net of income taxes Other 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. Prepaid expenses and other current assets Accounts payable Increase (Decrease) in Accounts Payable Accrued taxes Increase (Decrease) in Accrued Taxes Payable Changes in other assets Changes in other liabilities Cash Flows from Operating Activities 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, Investing Activities Other investing activities Cash Flows from (used in) Investing 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 Proceeds from long-term debt of variable interest entity ProceedsFromLTDVIE Proceeds From LTD VIE 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 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 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 from (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 Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents End of period Significant Accounting Policies [Text Block] Significant Accounting Policies [Text Block] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Adjustments to reconcile income to net cash from operating activities: Equity in earnings from subsidiaries Accounts receivable from subsidiaries Increase (Decrease) in Due from Related Parties Accounts payable to subsidiaries Increase (Decrease) in Accounts Payable, Related Parties Cash dividends from subsidiaries SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Consolidated Subsidiaries Net Cash Provided by (Used in) Operating Activities Investment in subsidiary Payments to Acquire Interest in Subsidiaries and Affiliates Net Cash Provided by (Used in) Investing Activities Issuance of common stock Proceeds from Issuance of Common Stock Issuance of preferred stock Proceeds from Issuance of Preferred Stock and Preference Stock Net cash from financing activities Net Change in Cash and Cash Equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and Cash Equivalents at Beginning of Year Cash and Cash Equivalents at End of Period Earnings Per Share [Abstract] Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Weighted Average Number Diluted Shares Outstanding Adjustment Weighted Average Number Diluted Shares Outstanding Adjustment Weighted Average Number of Shares Outstanding, Diluted Earnings Per Share, Basic and Diluted Earnings Per Share, Basic and Diluted Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 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) Property, Plant and Equipment Disclosure [Text Block] Property, Plant and Equipment Disclosure [Text Block] Regulatory Liabilities [Abstract] Regulatory Liabilities [Abstract] Schedule of Regulatory Liabilities [Table] Schedule of Regulatory Liabilities [Table] Regulatory Liability [Axis] Regulatory Liability [Axis] Regulatory Liability [Domain] Regulatory Liability [Domain] Taxes refundable through future rates [Member] Deferred Refundable Income Taxes [Member] Rate action of a regulator resulting in the return of income tax refunds to customers through future rates. Deferred regulatory gain from sale leaseback [Member] Deferred regulatory gain from sale leaseback [Member] Discloses the gain KGE recorded on the 1987 sale and leaseback of its 50% interest in La Cygne Unit 2. Emission allowances [Member] Emission Allowances [Member] Discloses the amount of regulatory liability arising from emission allowances sales. Nuclear decommissioning [Member] Nuclear decommissioning [Member] Discloses the difference between the fair value of the assets held in the nuclear decommissioning trust and the amount recorded for the accumulated accretion and depreciation expense associated with the asset retirement obligation elated to Wolf Creek. Pension and Other Postretirement Plans Costs [Member] Jurisdictional allowance for funds used during construction [Member] Jurisdictional Allowance For Funds Used During Construction [Member] Discloses AFUDC that is accrued subsequent to the time the associated construction charges are included in prices and prior to the time the related assets are placed in service. La Cygne leasehold dismantling costs [Member] La Cygne Leasehold Dismantling Costs [Member] Discloses amounts collected but not yet spent on the contractual obligation to dismantle a portion of La Cygne Unit 2. Kansas tax credits [Member] Kansas Tax Credits [Member] Discloses Kansas tax credits on investment in utility plant. Purchase power agreement [Member] Purchase Power Agreement [Member] Discloses the amount included in retail electric rates from customers in excess of costs incurred under purchase power agreements. Merger customer credits [Member] Merger Customer Credits [Member] Discloses one-time merger bill credits to KCP&L's Kansas electric retail customers. Refund of tax reform benefits [Member] Refund of tax reform benefits [Member] Discloses amounts collected from customers in 2018 related to federal income tax in excess of the income tax owed by the Evergy Companies as a result of the lower federal income tax rate enacted by the Tax Cuts and Jobs Act. Regulatory Liabilities [Line Items] Regulatory Liabilities [Line Items] Regulatory Liability, Current Regulatory Liabilities, Noncurrent Regulatory Liability, Amortization Period Regulatory Liability, Amortization Period Schedule of Quarterly Financial Information [Table Text Block] Quarterly Financial Information [Table Text Block] Statement of Stockholders' Equity [Abstract] Dividends declared on common stock (in dollars per share) Common Stock, Dividends, Per Share, Declared Organization, Consolidation and Presentation of Financial Statements [Abstract] Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Disaggregation of Revenue Disaggregation of Revenue [Table 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] Performance Shares [Member] Performance Shares [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 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 Revenue Revenue from Contract with Customer [Text Block] Schedule of Short-term Debt [Table Text Block] Schedule of Short-term Debt [Table Text Block] Rate Matters and Regulation [Abstract] Rate Matters and Regulation [Abstract] Schedule of Regulatory Assets [Table Text Block] Schedule of Regulatory Assets [Table Text Block] Schedule of Regulatory Liabilities [Table Text Block] Schedule of Regulatory Liabilities [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] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Geographic Distribution, Foreign [Member] Geographic Distribution, Foreign [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 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] Debt Security, Government, Non-US [Member] Debt Security, Government, Non-US [Member] Cash Equivalents [Member] Cash Equivalents [Member] Commodity Contract [Member] Commodity Contract [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] 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] Assets [Abstract] Assets, Fair Value Disclosure [Abstract] Total Derivative Assets (Liabilities), at Fair Value, Net Derivative Assets (Liabilities), at Fair Value, Net Derivative, Fair Value, Net Derivative, Fair Value, Net Cash and Cash Equivalents, Fair Value Disclosure Cash and Cash Equivalents, Fair Value Disclosure Level 2 transferred to Level 1 Level 2 transferred to NAV Estimates Of Environmental Financial Impact And Related Issues [Table] Estimates Of Environmental Financial Impact And Related Issues [Table] Supply Commitment [Axis] Supply Commitment [Axis] Supply Commitment Arrangement [Domain] Supply Commitment Arrangement [Domain] Supply Commitment [Member] Supply Commitment [Member] Jeffrey Units Nos 1 and 2 [Member] JointlyOwnedElectricityGenerationsPlantJeffrey Units Nos 1 and 2 [Member] Jeffrey Units Number 1 and 2, a jointly owned plant in connection with generation of electricity, excluding nuclear. Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] MISSOURI MISSOURI KANSAS KANSAS Estimates Of Environmental Financial Impact And Related Issues [Line Items] Estimates Of Environmental Financial Impact And Related Issues [Line Items] Nuclear Insurance [Abstract] Nuclear Insurance [Abstract] Nuclear Insurance [Abstract] Industry Aggregate Limit For Nuclear Insurance Industry_Aggregate_Limit_For_Nuclear_Insurance Industry Aggregate Limit For Nuclear Insurance Industry Aggregate Limit For Non Nuclear Insurance IndustryAggregateLimitForNonNuclearInsurance Industry Aggregate Limit For Non NuclearInsuarnce Nuclear Liability Insurance [Abstract] Nuclear Liability Insurance [Abstract] Nuclear Liability Insurance [Abstract] Nuclear Liability Insurance, Full Limit Of Public Liability NuclearLiabilityInsuranceFullLimitOfPublicLiability Nuclear Liability Insurance Full Limit Of Public Liability Nuclear Liability Insurance, Maximum Available Commercial Insurance NuclearLiabilityInsuranceMaximumAvailableCommercialInsurance Nuclear Liability Insurance Maximum Available Commercial Insurance Nuclear Liability Insurance, Industry Wide Retrospective Assessment Program NuclearLiabilityInsuranceIndustryWideRetrospectiveAssessmentProgram Nuclear Liability Insurance Industry Wide Retrospective Assessment Program Nuclear Liability Insurance, Owners Insurance Amount, Maximum NuclearLiabilityInsuranceOwnersInsuranceAmountMaximum Nuclear Liability Insurance Owners Insurance Amount Maximum Nuclear Liability Insurance, Owners Insurance, Amount Per Incident NuclearLiabilityInsuranceOwnersInsuranceAmountPerIncident Nuclear Liability Insurance Owners Insurance Amount, Per Incident Nuclear Liability Insurance, Owners Property Insurance, Maximum NuclearLiabilityInsuranceOwnersPropertyInsuranceMaximum Nuclear Liability Insurance Owners Property Insurance Maximum Nuclear Liability Insurance, Owners Nonnuclear Property Insurance, Maximum NuclearLiabilityInsuranceOwnersNonnuclearPropertyInsuranceMaximum Nuclear Liability Insurance Owners Nonnuclear Property Insurance Maximum Nuclear Liability Insurance, Owners Property Insurance Assessment, Maximum NuclearLiabilityInsuranceOwnersPropertyInsuranceAssessmentMaximum Nuclear Liability Insurance Owners Property Insurance Assessment Maximum Schedule of Jointly Owned Utility Plants [Table Text Block] Schedule of Jointly Owned Utility Plants [Table Text Block] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Beginning balance 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 Total noncurrent asset retirement obligation Preferred Stock 3 Point 80 [Member] Preferred Stock 3 Point 80 [Member] 3.80% Preferred Stock Preferred Stock 4 Point 50 [Member] Preferred Stock 4 Point 50 [Member] 4.50% Preferred Stock Preferred Stock 4 Point 20 [Member] Preferred Stock 4 Point 20 [Member] 4.20% Preferred Stock Preferred Stock 4 Point 35 [Member] Preferred Stock 4 Point 35 [Member] 4.35% Preferred Stock Cumulative Preferred Stock [Member] Cumulative Preferred Stock [Member] Preference Stock Convertible Preferred Stock [Member] Accounts receivable from subsidiaries Due from Related Parties, Current Notes receivable from subsidiaries Notes Receivable, Related Parties, Current Prepaid expenses and other assets Total Current Assets Investment in subsidiaries Equity Method Investments Notes receivable from subsidiaries Notes Receivable, Related Parties, Noncurrent Deferred income taxes Deferred Tax Assets, Net, Noncurrent Total Other Assets Total Assets LIABILITIES AND EQUITY Accounts payable to subsidiaries Derivative instruments Derivative Liability, Current Total Current Liabilities Long-term debt, net Total Long-Term Liabilities EQUITY Capitalization, Long-term Debt and Equity [Abstract] Common stock Accumulated other comprehensive loss Total shareholders' equity Commitments and Contingencies 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 Schedule of Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Long-Term Debt Long-term Debt [Text Block] Summary of Tax Credit Carryforwards [Table Text Block] Summary of Tax Credit Carryforwards [Table Text Block] Summary of Operating Loss Carryforwards [Table Text Block] Summary of Operating Loss Carryforwards [Table Text Block] 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 Deferred Tax Assets and Liabilities [Table Text Block] Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Supplemental Cash Flow Information [Abstract] Variable Interest Entities [Member] Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member] Cash paid for (received from): Supplemental Cash Flow Elements [Abstract] Interest, net of amounts capitalized Interest Paid, Including Capitalized Interest, Operating and Investing Activities 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) NonCashPropertyPlantAndEquipmentAdditions(Reductions) Non-cash property, plant and equipment additions (reductions) 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 Schedule of Debt [Table Text Block] Schedule of Debt [Table Text Block] Schedule of Maturities of Long-term Debt [Table Text Block] Schedule of Maturities of Long-term Debt [Table Text Block] Summary Of Accounting Policies [Table] Summary Of Accounting Policies [Table] Summary Of Accounting Policies [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2017-07 [Member] Accounting Standards Update 2017-07 [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 2016-15 - 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 2016-18 [Member] Accounting Standards Update 2016-18 [Member] Scenario, Adjustment [Member] Scenario, Adjustment [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Prairie Wind Transmission, LLC [Member] Prairie Wind Transmission, LLC [Member] Prairie Wind Transmission, LLC [Member] Transource Energy, LLC [Member] Transource Energy, LLC [Member] Transource Energy, LLC Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] AEP Transmission Holding Company, LLC [Member] AEP Transmission Holding Company, LLC [Member] AEP Transmission Holding Company, LLC GPE Transmission Holding Company, LLC [Member] GPE Transmission Holding Company, LLC [Member] GPE Transmission Holding Company, LLC As Previously Reported [Member] Summary Of Accounting Policies [Line Items] Summary Of Accounting Policies [Line Items] [Line Items] for Summary Of Accounting Policies [Table] Pension and postretirement liability 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 and renewable purchased power Owned Generating Capacity And Renewable Purchased Power Owned Generating Capacity and Renewable Purchased Power Number of customers served Number Of Customers Served Number Of Customers Served Common Stock, Dividends, Per Share, Declared Dividends Payable Dividends Payable 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] Long-term Debt, Gross Derivative, Notional Amount Derivative, Notional Amount Business Acquisition, Fair Value Adjustment, Long-Term Debt Long-term Debt Long-term Debt, Fair Value Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Capital Leases, Minimum Annual Rental Payments [Abstract] Capital Leases, Minimum Annual Rental Payments [Abstract] Schedule of Capital Leased Assets [Table] Schedule of Capital Leased Assets [Table] Major Property Class [Axis] Major Property Class [Axis] Major Property Class [Domain] Major Property Class [Domain] Vehicles [Member] Vehicles [Member] Computer Equipment [Member] Computer Equipment [Member] Electric Generation Equipment [Member] Electric Generation Equipment [Member] Other Machinery and Equipment [Member] Other Machinery and Equipment [Member] Capital Leased Assets [Line Items] Capital Leased Assets [Line Items] 2019 Capital Leases, Future Minimum Payments Due, Next Twelve Months 2020 Capital Leases, Future Minimum Payments Due in Two Years 2021 Capital Leases, Future Minimum Payments Due in Three Years 2022 Capital Leases, Future Minimum Payments Due in Four Years 2023 Capital Leases, Future Minimum Payments Due in Five Years After 2023 Capital Leases, Future Minimum Payments Due Thereafter Total capital lease payments Capital Leases, Future Minimum Payments Due Amounts representing imputed interest Capital Leases, Future Minimum Payments, Interest Included in Payments Present value of net minimum lease payments under capital leases Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments Less: current portion Capital Lease Obligations, Current Total long-term obligations under capital leases Capital Lease Obligations, Noncurrent 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 [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 Merger of Great Plains Energy and Westar Energy Business Combination Disclosure [Text Block] Pension and Post-Retirement Benefits [Abstract] Pension and Post-Retirement Benefits [Abstract] Jointly Owned Nuclear Power Plant [Member] Other Postretirement Benefits Plan [Member] Retirement Plan Sponsor Location [Axis] Retirement Plan Sponsor Location [Axis] Retirement Plan Sponsor Location [Domain] Retirement Plan Sponsor Location [Domain] Retirement Plan Tax Status [Axis] Retirement Plan Tax Status [Axis] Retirement Plan Tax Status [Domain] Retirement Plan Tax Status [Domain] Retirement Plan Funding Status [Axis] Retirement Plan Funding Status [Axis] Retirement Plan Funding Status [Domain] Retirement Plan Funding Status [Domain] Retirement Plan Name [Axis] Retirement Plan Name [Axis] Retirement Plan Name [Domain] Retirement Plan Name [Domain] Bonds [Member] DefinedBenefitPlanBond [Member] Debt instruments issued by corporation, government and governmental agency, municipality, and other institution or funds that invest in such securities; in which defined benefit plan asset is invested. Mortgage & asset-backed securities [Member] Other investments DefinedBenefitPlanOtherInvestment [Member] Other investments in which defined benefit plan assets are invested. Investment Objective [Axis] Investment Objective [Axis] Investment Objective [Domain] Investment Objective [Domain] Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Defined Benefit Plan, Benefit Obligation, beginning of the year Defined Benefit Plan, Benefit Obligation Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Contributions by participants Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant Plan amendments Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment Actuarial (gain) loss Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Settlements and special termination benefits Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement Obligations assumed upon merger with Great Plains Energy Defined Benefit Plan, Benefit Obligation, Business Combination Other Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Other Change Defined Benefit Plan, Benefit Obligation, end of the year Change in plan assets Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Actual return on plan assets Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Contributions by employer and participants Defined Benefit Plan Contributions by Employer and Participants The increase in the fair value of plan assets from contributions made by the employer and plan participants. Benefits paid Defined Benefit Plan, Plan Assets, Benefits Paid Settlements Defined Benefit Plan, Plan Assets, Payment for Settlement Assets acquired upon merger with Great Plains Energy Defined Benefit Plan, Plan Assets, Business Combination Other DefinedBenefitPlanPlanAssetsOther Other increases (decreases) in plan assets. Fair value of plan assets, end of the year Funded status at end of year Defined Benefit Plan, Funded (Unfunded) Status of Plan Amounts recognized in the consolidated balance sheets Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract] Non-current asset Assets for Plan Benefits, Defined Benefit Plan Current pension and other post-retirement liability Liability, Pension and Other Postretirement and Postemployment Benefits, Current Noncurrent pension liability and other post-retirement liability Liability, Pension and Other Postretirement and Postemployment Benefits, Noncurrent Net amount recognized before regulatory treatment DefinedBenefitPlanAmountsRecognizedInBalanceSheetBeforeRegulatoryTreatment Amount of asset (liability), recognized in statement of financial position, for defined benefit pension and other postretirement plans, before regulatory treatment. Accumulated OCI or regulatory asset/liability DefinedBenefitPlanAmountRecognizedInAccumulatedOtherComprehensiveIncomeOrRegulatoryAssetLiability The aggregate amount recognized in accumulated other comprehensive income, regulatory assets and regulatory liabilities associated with the defined benefit plan(s). Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position Amounts in accumulated other comprehensive income or regulatory asset/liability not yet recognized as a component of net periodic benefit cost [Abstract] Amounts In Accumulated Other Comprehensive Income Or Regulatory Asset/Liability Not Yet Recognized As A Component Of Net Periodic Benefit Cost [Abstract] Amounts In Accumulated Other Comprehensive Income Or Regulatory Asset/Liability Not Yet Recognized As A Component Of Net Periodic Benefit Cost [Abstract] Actuarial (gain) loss DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeOrRegulatoryAssetLiabilityNetGainsLossesBeforeTax The pretax net amounts of gains and losses that are not yet recognized as a component of net periodic benefit cost, and that are recognized as increases or decreases in other comprehensive income or regulatory (assets) liabilities as they arise. Gains and losses are due to changes in the value of either the benefit obligation or the plan assets. Prior service cost DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeOrRegulatoryAssetLiabilityNetPriorServiceCostCreditBeforeTax Amount related to the pretax cost of benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation, which has not yet been recognized as components of net periodic benefit cost. Other DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeOrRegulatoryAssetLiabilityOtherBeforeTax Amount related to other amounts recorded in accumulated other comprehensive income or regulatory (assets) liabilities, before tax. Unfunded accumulated benefit obligation for non qualified plans UnfundedAccumulatedBenefitObligationForNonQualifiedPlans The unfunded accumulated benefit obligation related to non-qualified benefit plans. Segregated assets for non-qualified benefit plans SegregatedAssetsForNonQualifiedBenefitPlans Assets that have been segregated in trusts to cover the unfunded non-qualified benefit plans. Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] 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) Settlement and special termination benefits Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Recognized net actuarial (gain) loss Defined Benefit Plan, Amortization of Gain (Loss) Net periodic benefit costs before regulatory adjustment and intercompany allocations Net period benefit costs before regulatory adjustment And Intercompany Allocations The total amount of net periodic benefit cost for defined benefit plans for the period before regulatory adjustment and intercompany allocations. 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. Intercompany allocations DefinedBenefitPlansIntercompanyAllocations Increase (decrease) in net periodic benefit costs related to intercompany allocations. Net periodic benefit costs Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income Regulatory Assets/Liabilities [Abstract] Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income Regulatory Assets/Liabilities [Abstract] Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Income Regulatory Assets/Liabilities [Abstract] Current year net (gain) loss Other Comprehensive Income (Loss) Or Regulatory Asset Liability, Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax Amount before tax of (increase) decrease in the value of the projected benefit obligation related to a change in an actuarial assumption and increase (decrease) in the value of the plan assets resulting from experience different from that assumed, that has not been recognized in net periodic benefit (cost) credit. Amortization of gain (loss) Other Comprehensive Income (Loss) Or Regulatory Asset Liability, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax Amount before tax of reclassification adjustment from accumulated other comprehensive income (loss) or regulatory asset/liability related to pension and other postretirement benefit plans. Prior service cost Other Comprehensive (Income) Loss or Regulatory Asset Liability, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit) Arising During Period, before Tax Amount before tax of cost (credit) of benefit changes attributable to plan participants' prior service resulting from a plan amendment or plan initiation that has not been recognized in net periodic benefit costs (credit). Amortization of prior service cost Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI or Regulatory Asset Liability, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax Amount before tax of reclassification adjustment from accumulated other comprehensive (income) loss or regulatory asset/liability for prior service cost (credit) related to pension and other postretirement benefit plans. Other regulatory activity OtherComprehensiveIncomeLossOrRegulatoryAssetLiabilityPensionAndOtherPostretirementBenefitPlansOtherRegulatoryActivity Changes in pension and postretirement benefit plan assets and benefit obligations recognized in OCI or regulatory assets/liabilities due to other regulatory activity. Total Recognized In OCI Or Regulatory Asset Liability Total Recognized In Other Comprehensive Income Or Regulatory Asset Liability The total recognized in other comprehensive income or regulatory assets/liabilities. Total Recognized In Net Periodic Benefit Costs And OCI Or Regulatory Asset Liability Total Recognized In Net Periodic Benefit Costs And Other Comprehensive Income Or Regulatory Asset Liability Total recognized in net periodic benefit costs and other comprehensive income or regulatory asset/liability. Prior service cost amortization DefinedBenefitPlanFutureAmortizationOfPriorServiceCostFromAOCIOrRegulatoryAsset Amount included in accumulated other comprehensive income (AOCI) or a regulatory asset related to prior service cost (credit) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position. Actuarial gain (loss) amortization DefinedBenefitPlanFutureAmortizationOfGainLossFromAOCIOrRegulatoryAsset Amount included in accumulated other comprehensive income (AOCI) or a regulatory asset related to gain (loss) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position. ABO for all defined benefit pension plans Defined Benefit Plan, Accumulated Benefit Obligation Pension plans with the PBO in excess of plan assets Defined Benefit Plan, Pension Plan with Project Benefit Obligation in Excess of Plan Assets [Abstract] Projected benefit obligation Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation Fair value of plan assets Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract] Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract] Accumulated benefit obligation Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation Fair value of plan assets Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets Weighted-average assumptions used to determine the benefit obligation Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Rate of compensation increase Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Weighted-average assumptions used to determine net costs Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Expected long-term return on plan assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets Rate of compensation increase Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Contributions to plans in next year Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Defined Benefit Plan, Expected Future Benefit Payment [Abstract] Defined Benefit Plan, Expected Future Benefit Payment [Abstract] Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months Defined Benefit Plan, Expected Future Benefit Payment, Year Two Defined Benefit Plan, Expected Future Benefit Payment, Year Two Defined Benefit Plan, Expected Future Benefit Payment, Year Three Defined Benefit Plan, Expected Future Benefit Payment, Year Three Defined Benefit Plan, Expected Future Benefit Payment, Year Four Defined Benefit Plan, Expected Future Benefit Payment, Year Four Defined Benefit Plan, Expected Future Benefit Payment, Year Five Defined Benefit Plan, Expected Future Benefit Payment, Year Five Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter Defined Benefit Plan, Plan Assets, Allocations [Abstract] Defined Benefit Plan, Plan Assets, Allocations [Abstract] Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract] Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract] Health care cost trend rate assumed for next year Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year Rate to which the cost trend is assumed to decline (the ultimate trend rate) Defined Benefit Plan, Ultimate Health Care Cost Trend Rate Year that rate reaches ultimate trend Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate [Abstract] Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate [Abstract] Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation Employee Savings Plans Defined Contribution Plan [Abstract] Defined Contribution Plan, Cost Defined Contribution Plan, Cost Receivable Type [Axis] Customer Contracts [Member] Customer Contracts [Member] Impairment losses recognized on receivables Restricted cash Restricted Cash and Cash Equivalents Guarantees Guarantees [Text Block] Leases [Abstract] Public Utilities, Inventory, Fuel [Member] Other purchase commitments [Member] Capital Leased Assets, Gross Capital Leased Assets, Gross Capital Leases, Balance Sheet, Assets by Major Class, Net Capital Leases, Balance Sheet, Assets by Major Class, Net Accumulated amortization Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation Operating income Net Income (Loss) Attributable to Parent Earnings Per Share, Basic and Diluted Basic EPS Diluted EPS Schedule of Accounting Charges and Deferrals Related to Merger Schedule of Business Acquisitions, by Acquisition [Table Text Block] Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Table Text Block] Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Table Text Block] Schedule of Purchase Price Allocation 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] Equity Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Jointly Owned Electric Utility Plants [Text Block] Jointly Owned Electric Utility Plants [Text Block] The entire disclosure on jointly owned electric utility plants. Tax Reform [Abstract] Tax Reform [Abstract] 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 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 Merger-related after-tax financing costs BusinessCombinationFinancingRelatedChargesAfterTax Business combination, financing related charges, after tax Merger contingent, after-tax mark-to-market interest rate swap gains MergerContingentAfterTaxMarkToMarketInterestRateSwapGains Merger contingent after-tax mark-to-market interest rate swap gains Merger-related, reductions of revenues for customer bill credits BusinessCombinationOneTimeBillCredits,AfterTax Merger-related reductions to revenue as a result of one-time customer bill credits, after tax. New Accounting Standards [Abstract] New Accounting Standards [Abstract] Accounting Standards Update 2016-02 [Member] Accounting Standards Update 2016-02 [Member] 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] Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Increase in Assets from ASU 2016-02 Increase in Assets from ASU 2016-02 Increase in Assets from ASU 2016-02 New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Schedule of Capital Leased Assets [Table Text Block] Schedule of Capital Leased Assets [Table Text Block] Schedule of Future Minimum Lease Payments for Capital Leases [Table Text Block] Schedule of Future Minimum Lease Payments for Capital Leases [Table Text Block] Contractual Obligation, Fiscal Year Maturity Schedule [Table Text Block] Contractual Obligation, Fiscal Year Maturity Schedule [Table Text Block] Shareholders' Equity Stockholders' Equity Note Disclosure [Text Block] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] VIE ownership percentage Property, plant and equipment 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 [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 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 Repurchase of common stock Stock Repurchased During Period, Shares 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 Change in unrecognized pension expense, net of tax Other Stockholders' Equity, Other Ending balance (in shares) Ending balance New Accounting Pronouncements or Change in Accounting Principle [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Abstract] Adjustments for Error Corrections [Axis] Adjustments for Error Corrections [Axis] Adjustments for Error Correction [Domain] Adjustments for Error Correction [Domain] Operating and maintenance expense Income from operations Other expense Total other income (expense), net