Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets [Text Block]
Goodwill and Intangible Assets Disclosure [Text Block]
Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts Disclosure [Table]
Valuation Allowances and Reserves Type [Axis]
Valuation Allowances and Reserves [Domain]
Allowance for Doubtful Accounts [Member]
Legal Reserve [Member]
Reserve for Environmental Costs [Member]
Valuation Allowance of Deferred Tax Assets [Member]
Legal Entity [Axis]
Entity [Domain]
Kansas City Power and Light Company [Member]
Subsidiaries [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period
Valuation Allowances and Reserves, Balance
Additions charged to costs and expenses
Valuation Allowances and Reserves, Charged to Cost and Expense
Additions charged to other accounts
Valuation Allowances and Reserves, Charged to Other Accounts
Deductions
Valuation Allowances and Reserves, Deductions
Balance at end of period
Short-term Borrowings and Short-term Bank Lines of Credit [Abstract]
Short-term Borrowings and Short-term Bank Lines of Credit [Text Block]
Short-term Debt [Text Block]
Guarantees [Abstract]
Schedule of Guarantor Obligations [Table]
Schedule of Guarantor Obligations [Table]
Legal Entity [Axis]
Entity [Domain]
KCPL Greater Missouri Operations [Member]
Kcpl Greater Missouri Operations Member
Information on KCPL Greater Missouri Operations.
Guarantor Obligations, Nature [Axis]
Guarantor Obligations, Nature [Axis]
Guarantor Obligations, Nature [Domain]
Guarantor Obligations, Nature [Domain]
Direct Guarantee [Member]
Direct Guarantee [Member]
An agreement (contract) that requires the guarantor to make payments to the guaranteed party based on another entity's failure to pay specified obligations.
Standby Letters of Credit [Member]
Standby Letters of Credit [Member]
Guarantee of Indebtedness of Others [Member]
Guarantee of Indebtedness of Others [Member]
Revolving Credit Facility [Member]
Revolving Credit Facility [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted
Guarantor Obligations, Maximum Exposure, Undiscounted
Guarantor Obligations, Term
Guarantor Obligations, Term
Commercial paper
Commercial Paper
Commercial paper outstanding
Letters of Credit Outstanding, Amount
Letters of Credit Outstanding, Amount
Amount of outstanding cash borrowings
Short-term Bank Loans and Notes Payable
Compensation and Retirement Disclosure [Abstract]
Schedule of Defined Benefit Plans Disclosures [Table]
Defined Benefit Plans and Other Postretirement Benefit Plans [Axis]
Defined Benefit Plans and Other Postretirement Benefit Plans [Domain]
Pension Plans, Defined Benefit [Member]
Pension Plans, Defined Benefit [Member]
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer
Change in projected benefit obligation [Roll Forward]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation
Defined Benefit Plan, Benefit Obligation
Service cost
Defined Benefit Plan, Service Cost
Interest cost
Defined Benefit Plan, Interest Cost
Defined Benefit Plan, Contributions by Plan Participants
Defined Benefit Plan, Contributions by Plan Participants
Defined Benefit Plan, Plan Amendments
Defined Benefit Plan, Plan Amendments
Actuarial (gain) loss
Defined Benefit Plan, Actuarial Gain (Loss)
Defined Benefit Plan, Benefits Paid
Defined Benefit Plan, Benefits Paid
Defined Benefit Plan, Settlements, Benefit Obligation
Defined Benefit Plan, Settlements, Benefit Obligation
Defined Benefit Plan, Benefit Obligation
Change in plan assets [Roll Forward]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of the year
Defined Benefit Plan, Fair Value of Plan Assets
Actual return on plan assets
Defined Benefit Plan, Actual Return on Plan Assets
Defined benefit plan, 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.
Defined benefit plan, benefits paid, portion paid from plan assets
Defined Benefit Plan Benefits Paid Portion Paid from Plan Assets
The amount of payments paid from plan assets for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets.
Fair value of plan assets at end of the year
Funded status at end of year
Defined Benefit Plan, Funded Status of Plan
Amounts recognized in the consolidated balance sheets [Abstract]
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent
Defined Benefit Plan Amounts Recognized in Balance Sheet before Regulatory Treatment
Defined Benefit Plan Amounts Recognized in Balance Sheet before Regulatory Treatment
The aggregate net amount recognized in the balance sheet associated with the defined benefit plan(s) before OCI/regulatory treatment.
Defined benefit plan amount recognized in Accumulated Other Comprehensive Income or regulatory asset/liability
Defined benefit plan amount recognized in Accumulated Other Comprehensive Income or Regulatory Asset Liability
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 Recognized in Balance Sheet
Defined Benefit Plan, Amounts Recognized in Balance Sheet
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]
-- None. No documentation exists for this element. --
Defined Benefit Plan Accumulated Other Comprehensive Income Or Regulatory Asset/Liability Net Gains/Losses Before Tax
Defined Benefit Plan Accumulated Other Comprehensive Income Or Regulatory Asset Liability Net Gains Losses Before Tax
The pretax net amount 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.
Defined Benefit Plan Accumulated Other Comprehensive Income Or Regulatory Asset/Liability Net Prior Service Cost Credit Before Tax
Defined Benefit Plan Accumulated Other Comprehensive Income Or Regulatory Asset Liability Net Prior Service Cost Credit Before Tax
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.
Defined Benefit Plan Accumulated Other Comprehensive Income Or Regulatory Asset/Liability Net Transition Obligation Before Tax
Defined Benefit Plan Accumulated Other Comprehensive Income Or Regulatory Asset Liability Net Transition Obligation Before Tax
Of the original amount of transition assets as of the date FAS 87 or 106 was initially applied, the portion of which has yet to be recognized as components of net periodic benefit cost. This amount is pretax.
Defined Benefit Plan Accumulated Other Comprehensive Income Other Before Tax
Defined Benefit Plan Accumulated Other Comprehensive Income Other Before Tax
Amount related to other amounts recorded in accumulated other comprehensive income or regulatory (assets) liabilities, before tax.
Components of net periodic benefit costs [Abstract]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan, Expected Return on Plan Assets
Defined Benefit Plan, Expected Return on Plan Assets
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)
Defined Benefit Plan, Amortization of Gains (Losses)
Defined Benefit Plan, Amortization of Gains (Losses)
Defined Benefit Plan, Amortization of Transition Obligations (Assets)
Defined Benefit Plan, Amortization of Transition Obligations (Assets)
Settlement charges
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements
Net periodic benefit costs before regulatory adjustment
Net period benefit costs before regulatory adjustment
The total amount of net periodic benefit cost for defined benefit plans for the period before regulatory adjustment. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.
Defined benefit plan, regulatory adjustment
Defined benefit plan, Regulatory adjustment
The element used to encapsulate periodic benefit costs related to regulatory adjustments.
Defined Benefit Plan, Net Periodic Benefit Cost
Defined Benefit Plan, Net Periodic Benefit Cost
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]
-- None. No documentation exists for this element. --
Net gain (loss) arising during period
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax
Prior service cost
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Arising During Period, before Tax
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Benefit Cost, before Tax
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Benefit Cost, before Tax
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Transition Asset (Obligation), Recognized in Net Periodic Benefit Cost, before Tax
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Transition Asset (Obligation), Recognized in Net Periodic Benefit Cost, before Tax
Other regulatory activity
Defined Benefit Plan, Other Costs
Total Recognized In Other Comprehensive Income 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 Other Comprehensive Income 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.
Estimated prior service cost that will be amortized in the next fiscal year
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit)
Net loss for the defined benefit plans that will be amortized in the next fiscal year
Defined Benefit Plan, Amortization of Net Gains (Losses)
Transition costs for the defined benefit plans that will be amortized in the next fiscal year
Defined Benefit Plan, Amortization of Net Transition Asset (Obligation)
Length Of Time For Amortization Of Net Actuarial Gains And Losses For Financial Reporting Purposes
Length Of Time For Amortization Of Net Actuarial Gains And Losses For Financial Reporting Purposes
The length of time for amortization of net actuarial gains and losses for financial reporting purposes.
Length Of Time For Amortization Of Net Actuarial Gains And Losses For Regulatory Reporting Purposes
Length Of Time For Amortization Of Net Actuarial Gains And Losses For Regulatory Reporting Purposes
The length of time for amortization of net actuarial gains and losses for regulatory reporting purposes.
Accumulated benefit obligation (ABO) for all defined benefit plans
Defined Benefit Plan, Accumulated Benefit Obligation
Pension plans with the accumulated benefit obligation in excess of plans assets [Abstract]
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets [Abstract]
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit Obligation
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit Obligation
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Accumulated Benefit Obligation
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Accumulated Benefit Obligation
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets
Unfunded accumulated benefit obligation for GMO SERP
Unfunded accumulated benefit obligation for GMO SERP
The unfunded accumulated benefit obligation related to the GMO SERP acquired in the GMO acquisition.
Segregated assets for GMO SERP
Segregated assets for GMO SERP
Assets that have been segregated to cover the unfunded GMO SERP acquired in the GMO acquisition.
Pension plans with plan assets in excess of accumulated benefit obligations [Abstract]
Pension Plans With Plan Assets In Excess Of Accumulated Benefit Obligations [Abstract]
Defined benefit plans with plan assets in excess of accumulated benefit obligations, projected benefit obligation
Defined benefit plans with plan assets in excess of accumulated benefit obligations projected benefit obligation
If aggregate disclosures are presented, the aggregate benefit obligation for plans with plan assets in excess of accumulated benefit obligations as of the measurement date of each statement of financial position presented.
Defined benefit plans with plan assets in excess of accumulated benefit obligations, accumulated benefit obligation
Defined benefit plans with plan assets in excess of accumulated benefit obligations, accumulated benefit obligation
If aggregate disclosures are presented, the aggregate pension accumulated benefit obligation for pension plans with plan assets in excess of accumulated benefit obligations as of the measurement date of each statement of financial position presented.
Defined benefit plans with plan assets in excess of accumulated benefit obligations, fair value of plan assets
Defined benefit plans with plan assets in excess of accumulated benefit obligations, fair value of plan assets
If aggregate disclosures are presented, the aggregate fair value of plan assets for pension plans with plan assets in excess of accumulated benefit obligations as of the measurement date of each statement of financial position presented.
Weighted average assumptions used to determine the benefit obligation [Abstract]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase
Weighted average assumptions used to determine net costs [Abstract]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase
Contribute to plans in next year
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months
Defined Benefit Plan, Expected Future Benefit Payments, Year Two
Defined Benefit Plan, Expected Future Benefit Payments, Year Two
Defined Benefit Plan, Expected Future Benefit Payments, Year Three
Defined Benefit Plan, Expected Future Benefit Payments, Year Three
Defined Benefit Plan, Expected Future Benefit Payments, Year Four
Defined Benefit Plan, Expected Future Benefit Payments, Year Four
Defined Benefit Plan, Expected Future Benefit Payments, Year Five
Defined Benefit Plan, Expected Future Benefit Payments, Year Five
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter
Defined Benefit Plan, Target Allocation Percentage
Defined Benefit Plan, Target Allocation Percentage
Health care cost trend (in hundredths)
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year
Health care cost rate declining through
Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate
Ultimate cost trend rate (in hundredths)
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate
Effect on total service and interest component, increase
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components
Effect on total service and interest component, decrease
Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components
Effect on post-retirement benefit obligation, increase
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation
Effect on post-retirement benefit obligation, decrease
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation
Employee Savings Plans [Abstract]
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Defined contribution savings plan, cost of plan
Defined Contribution Plan, Cost Recognized
Voluntary Separation Program [Abstract]
Voluntary Separation Program [Abstract]
Voluntary separation program
Voluntary Separation Program
Statement of Cash Flows [Abstract]
Statement [Table]
Statement [Table]
Parent Company [Member]
Parent Company [Member]
Scenario [Axis]
Scenario [Axis]
Scenario, Unspecified [Domain]
Scenario, Unspecified [Domain]
Statement [Line Items]
Statement [Line Items]
Cash Flows from Operating Activities
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest
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
Amortization
Deferred income taxes, net
Deferred Income Tax Expense (Benefit)
Equity in earnings (loss) from Subsidiaries
Equity in earnings (loss) from Subsidiaries
Income or loss from subsidiaries.
Cash flows affected by changes in:
Increase (Decrease) in Operating Capital [Abstract]
Accounts receivable from subsidiaries
Increase (Decrease) in Due from Related Parties
Taxes receivable
Increase (Decrease) in Income Taxes Receivable
Accounts payable to subsidiaries
Increase (Decrease) in Due to Related Parties
Other accounts payable
Increase (Decrease) in Other Accounts Payable and Accrued Liabilities
Accrued taxes
Increase (Decrease) in Accrued Taxes Payable
Accrued interest
Increase (Decrease) in Interest Payable, Net
Cash dividends from subsidiaries
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries
Interest rate hedge settlement
Forward starting swaps settlement
The amount of cash paid during the current period for settlement of forward starting swaps
Other operating activities
Other Operating Activities, Cash Flow Statement
Net cash from operating activities
Net Cash Provided by (Used in) Operating Activities
Cash Flows from Investing Activities
Net Cash Provided by (Used in) Investing Activities [Abstract]
Intercompany lending
Intercompany lending
Cash outflows (inflows) from intercompany lending.
Net money pool lending
Net money pool lending
Net money pool lending
Net cash from investing activities
Net Cash Provided by (Used in) Investing Activities
Cash Flows from Financing Activities
Net Cash Provided by (Used in) Financing Activities [Abstract]
Issuance of common stock
Proceeds from Issuance of Common Stock
Issuance of long-term debt
Proceeds from Issuance of Long-term Debt
Issuance fees
Payment of Financing and Stock Issuance Costs
Net change in short-term borrowings
Proceeds from (Repayments of) Short-term Debt
Dividends paid
Payments of Dividends
Other financing activities
Proceeds from (Payments for) Other Financing Activities
Net cash from financing activities
Net Cash Provided by (Used in) 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 Carrying Value
Cash and Cash Equivalents at End of Year
Schedule of Finite-Lived Intangible Assets [Table Text Block]
Schedule of Finite-Lived Intangible Assets [Table Text Block]
Amortization Expense Related to Intangible Assets [Table Text Block]
Amortization Expense Related to Intangible Assets [Table Text Block]
Schedule of amortization expense related to intangible assets by entity.
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Values of open positions for derivative instruments [Table Text Block]
Schedule of Derivative Instruments [Table Text Block]
Fair value of open derivative positions, gross values before netting agreements and netting of cash collatral [Table Text Block]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]
Gain (loss) recognized in other comprehensive income or earnings for interest rate and commodity hedges [Table Text Block]
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]
Gain (loss) recognized in a regulatory balance sheet account or earnings for utility commodity hedges [Table Text Block]
Derivative Instruments Recognized In Regulatory Assets [Text Block]
This element can be used for disclosing the entity's tabular disclosure of utility commodity derivatives fair value changes recorded to either a regulatory asset or liability consistent with Missouri Public Service Commission regulatory orders
Accumulated other comprehensive income related to cash flow hedges [Table Text Block]
Schedule Of Derivative Instruments Related To Cash Flow Hedges In Accumulated Other Comprehensive Income [Text Block]
This element can be used for disclosing the entity's tabular disclosure cash flow hedges included in accumulated other comprehensive income.
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies
Commitments and Contingencies Disclosure [Text Block]
Statement of Financial Position [Abstract]
Class of Stock [Axis]
Class of Stock [Axis]
Class of Stock [Domain]
Class of Stock [Domain]
Cumulative Preferred Stock [Member]
Cumulative Preferred Stock [Member]
Preferred Stock by Name [Axis]
Preferred Stock by Name [Axis]
The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table.
Preferred Stock, Class [Domain]
Preferred Stock, Class [Domain]
Type or class of preferred stock or special stock.
Preferred Stock 3 Point 80 [Member]
Preferred Stock Dividend Rate 1 [Member]
Preferred stock upon which unpaid dividends accumulate until paid to shareholders. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer. Shares issued for 3.80% cumulative preferred stock.
Preferred Stock 4 Point 50 [Member]
Preferred Stock Dividend Rate 2 [Member]
Preferred stock upon which unpaid dividends accumulate until paid to shareholders. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer. Shares issued for 4.50% cumulative preferred stock.
Preferred Stock 4 Point 20 [Member]
Preferred Stock Dividend Rate 3 [Member]
Preferred stock upon which unpaid dividends accumulate until paid to shareholders. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer. Shares issued for 4.20% cumulative preferred stock.
Preferred Stock 4 Point 35 [Member]
Preferred Stock Dividend Rate 4 [Member]
Preferred stock upon which unpaid dividends accumulate until paid to shareholders. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer. Shares issued for 4.35% cumulative preferred stock.
ASSETS
Assets [Abstract]
Current Assets
Assets, Current [Abstract]
Cash and cash equivalents
Funds on deposit
Deposits Assets, Current
Receivables, net
Receivables, Net, Current
Accounts receivable pledged as collateral
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount
Fuel inventories, at average cost
Energy Related Inventory
Materials and supplies, at average cost
Other Inventory, Supplies, Gross
Deferred refueling outage costs
Deferred refueling outage costs
Sum of the carrying amounts of deferred costs for nuclear plant refueling outages that are expected to be recognized as a charge against earnings.
Refundable income taxes
Income Taxes Receivable, Current
Deferred income taxes
Deferred Tax Assets, Net of Valuation Allowance, Current
Derivative instruments
Derivative Assets, Current
Prepaid expenses and other assets
Prepaid Expense, Current
Assets, Current, Total
Assets, Current
Utility Plant, at Original Cost
Public Utilities, Property, Plant and Equipment, Net [Abstract]
Electric
Public Utilities, Property, Plant and Equipment, Plant in Service
Less-accumulated depreciation
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation
Net utility plant in service
Public Utilities, Property, Plant and Equipment in service, Net
Period end amount of total net PPE in service
Construction work in progress
Public Utilities, Property, Plant and Equipment, Construction Work in Progress
Nuclear Fuel, Net of Amortization
Nuclear Fuel, Net of Amortization
Public Utilities, Property, Plant and Equipment, Net
Public Utilities, Property, Plant and Equipment, Net
Investments and Other Assets
Investments And Other Assets [Abstract]
Nuclear decommissioning trust fund
Decommissioning Fund Investments
Regulatory Assets
Regulatory Assets, Noncurrent
Goodwill
Goodwill
Derivative instruments
Derivative Assets, Noncurrent
Other Assets, Noncurrent
Investments and Other Assets, Total
Investments And Other Assets
The total of investments and other long-term assets.
Assets, Total
Assets
LIABILITIES AND CAPITALIZATION
Liabilities and Equity [Abstract]
Current Liabilities
Liabilities, Current [Abstract]
Notes payable
Collateralized note payable
Transfers Accounted for as Secured Borrowings, Associated Liabilities, Carrying Amount
Current maturities of long-term debt
Long-term Debt, Current Maturities
Accounts payable
Accounts Payable, Current
Affiliated payables
Accounts Payable, Related Parties, Current
Accrued taxes
Taxes Payable, Current
Accrued interest
Interest Payable, Current
Accrued compensation and benefits
Employee-related Liabilities, Current
Pension and post-retirement liability
Derivative instruments
Derivative Liabilities, Current
Other Liabilities, Current
Liabilities, Current, Total
Liabilities, Current
Deferred Credits and Other Liabilities
Liabilities, Noncurrent [Abstract]
Deferred income taxes
Deferred Tax Liabilities, Net, Noncurrent
Deferred tax credits
Accumulated Deferred Investment Tax Credit
Asset retirement obligations
Asset Retirement Obligations, Noncurrent
Pension and post-retirement liability
Regulatory Liabilities
Regulatory Liability, Noncurrent
Other Liabilities, Noncurrent
Liabilities, Noncurrent, Total
Liabilities, Noncurrent
Capitalization
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Common shareholders' equity
Stockholders' Equity Attributable to Parent [Abstract]
Common Stock, Value, Issued
Common Stock, Value, Issued
Retained earnings
Retained Earnings (Accumulated Deficit)
Treasury Stock, Value
Treasury Stock, Value
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss), Net of Tax
Common Shareholders' Equity, Total
Common Stockholders' Equity
Noncontrolling interest
Stockholders' Equity Attributable to Noncontrolling Interest
Cumulative preferred stock $100 par value
Preferred Stock, Value, Outstanding [Abstract]
Preferred Stock, Value, Issued
Preferred Stock, Value, Issued
Long-term debt
Long-term Debt, Excluding Current Maturities
Total Capitalization
Capitalization, Long-term Debt and Equity
Commitments and Contingencies
Commitments and Contingencies
Liabilities and Equity, Total
Liabilities and Equity
Accounting Policies [Abstract]
Summary of Significant Accounting Policies [Text Block]
Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block]
Segment Reporting [Abstract]
Segment financial information
Schedule of Segment Reporting Information, by Segment [Table Text Block]
Trading Activities, Gain and Losses, by Type, by Income Statement Location [Table]
Trading Activities, Gain and Losses, by Type, by Income Statement Location [Table]
Hedging Designation [Axis]
Hedging Designation [Axis]
Hedging Designation [Domain]
Hedging Designation [Domain]
Not Designated as Hedging Instrument [Member]
Not Designated as Hedging Instrument [Member]
Trading Activity, by Type [Axis]
Trading Activity [Axis]
Trading Activity, by Type [Domain]
Trading Activity, by Type [Domain]
Commodity [Member]
Commodity [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading Activity, Gains and Losses, Net [Line Items]
Gains (losses) reflected in the income statement for changes in fair value of commodity contracts not designated as hedging
Trading Activity, Gains and Losses, Net
Income Statement [Abstract]
Operating Revenues
Electric Revenue [Abstract]
Electric revenues
Electric Revenue
Operating Expenses
Costs and Expenses [Abstract]
Fuel
Utilities Operating Expense, Fuel Used
Purchased power
Utilities Operating Expense, Purchased Power
Transmission of electricity by others
Cost of Transmission, Other
Utility operating and maintenance expenses
Utilities Operating Expense, Maintenance and Operations
Depreciation and amortization
Depreciation, Depletion and Amortization, Nonproduction
General taxes
Taxes, Miscellaneous
Other General and Administrative Expense
Costs and Expenses, Total
Costs and Expenses
Operating Income (Loss)
Operating Income (Loss)
Non-operating income
Nonoperating income
Equity component of Allowance for Funds Used During Construction and the aggregate amount of other income amounts resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) profits on securities (net of losses), and (d) miscellaneous other income items.
Non-operating expenses
Other Nonoperating Expense
Interest charges
Interest Expense
Income before income tax (expense) benefit and income (loss) from equity investments
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest
Income tax (expense) benefit
Income Tax Expense (Benefit)
Loss from equity investments, net of income taxes
Income (Loss) from Equity Method Investments
Income from continuing operations
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest
Income (loss) from discontinued operations, net of income taxes
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest
Net income
Less: Net income attributable to noncontrolling interest
Net Income (Loss) Attributable to Noncontrolling Interest
Net income (loss) attributable to Great Plains Energy
Net Income (Loss) Attributable to Parent
Preferred stock dividend requirements
Preferred Stock Dividends, Income Statement Impact
Earnings available for common shareholders
Net Income (Loss) Available to Common Stockholders, Basic
Average number of common shares outstanding (in shares)
Weighted Average Number of Shares Outstanding, Basic
Average number of diluted common shares outstanding
Weighted Average Number of Shares Outstanding, Diluted
Basic earnings (loss) per common share
Earnings Per Share, Basic [Abstract]
Continuing operations
Income (Loss) from Continuing Operations, Per Basic Share
Discontinued operations
Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share
Basic earnings per common share
Earnings Per Share, Basic
Diluted earnings (loss) per common share
Earnings Per Share, Diluted [Abstract]
Continuing operations
Income (Loss) from Continuing Operations, Per Diluted Share
Discontinued operations
Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share
Diluted earnings per common share
Earnings Per Share, Diluted
Cash dividends per common share
Common Stock, Dividends, Per Share, Declared
Comprehensive Income
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Other comprehensive income
Other Comprehensive Income (Loss), Net of Tax [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)
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 on Derivatives Included in Net Income, Net of Tax
Derivative hedging activity, net of tax
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax
Net gain (loss) arising during period
Amortization of net losses included in net periodic benefit costs
Income tax benefit (expense)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax
Net change in unrecognized pension expense
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax
Comprehensive income attributable to Great Plains Energy
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Less: comprehensive income attributable to noncontrolling interest
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest
Comprehensive income
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest
Other comprehensive income (loss)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Statement of Stockholders' Equity [Abstract]
Equity Components [Axis]
Equity Components [Axis]
Equity Component [Domain]
Equity Component [Domain]
Stock Transactions, Parenthetical Disclosures [Abstract]
Stock Transactions, Parenthetical Disclosures [Abstract]
Common Stock, Dividends, Per Share, Declared
Related Party Transactions [Abstract]
Related Party Transactions and Relationships
Related Party Transactions Disclosure [Text Block]
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred Stock [Text Block]
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]
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]
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
Expected revised current deferred income tax asset for net operating losses
Expected revised current deferred income tax asset for net operating losses
Expected revised amount of current deferred income tax asset for net operating losses in first quarter of 2013 as a result of extended bonus depreciation due to the American Taxpayer Relief Act of 2012
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
Quarterly Financial Data [Abstract]
Operating revenues
Operating income (loss)
Net income
Net income (loss) attributable to Great Plains Energy
Earnings Per Share, Basic
Earnings Per Share, Diluted
Earnings Per Share, Basic and Diluted
Earnings Per Share, Basic and Diluted
Income [Abstract]
Earnings Per Share Reconciliation [Abstract]
Less: net income (loss) attributable to noncontrolling interest
Net Income (Loss) Attributable to Noncontrolling Interest, Other
Less: preferred stock dividend requirements
Common Shares Outstanding [Abstract]
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Add: effect of dilutive securities (in shares)
Weighted Average Number Diluted Shares Outstanding Adjustment
Diluted average number of common shares outstanding (in shares)
Earnings per share [Abstract]
Earnings Per Share [Abstract]
Pension Plans and Other Employee Benefits
Pension and Other Postretirement Benefits Disclosure [Text Block]
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule of Condensed Financial Statements [Table]
Condensed Financial Information of Parent Company Only Disclosure [Text Block]
Legal Proceedings [Abstract]
Loss Contingencies [Table]
Loss Contingencies [Table]
Loss Contingencies by Nature of Contingency [Axis]
Loss Contingency Nature [Axis]
Loss Contingency, Nature [Domain]
Loss Contingency, Nature [Domain]
Pending Litigation [Member]
Pending Litigation [Member]
Total Wolf Creek including KCPL [Member]
Total Wolf Creek including KCPL [Member]
Total Wolf Creek includng KCPL.
Loss Contingencies [Line Items]
Loss Contingencies [Line Items]
Approximate amount of refunds received as a net purchaser of power through settlements with sellers of power
Approximate Amount Of Refund Received From Various Providers
The approximate amount of refunds received by MPS Merchant Services, Inc., a wholly owned subsidiary of KCP and L Greater Missouri Operations Company, for net purchases of power in the California energy markets between October 2, 2000 through June 20, 2001.
Estimated additional refunds entitled to receive
Estimated Additional Refunds Entitled To Receive
Estimated additional refunds entitled to receive.
Amount of claims addressed under refund proceedings
Loss Contingency, Damages Sought, Value
Nuclear Plant [Abstract]
Nuclear Plant
Schedule Of Nuclear Plant [Text Block]
This element can be used to encapsulate the entire disclosure for plant used in connection with the generation of nuclear energy.
Fair Value, by Balance Sheet Grouping [Table]
Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis]
Fair Value, Disclosure Item Amounts [Domain]
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of financial instruments [Abstract]
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Long-term Debt
Long-term Debt
Long-term Debt, Fair Value
Long-term Debt, Fair Value
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table]
Antidilutive Securities Excluded from Computation of Earnings Per Share, by Antidilutive Securities [Axis]
Antidilutive Securities [Axis]
Antidilutive Securities, Name [Domain]
Antidilutive Securities, Name [Domain]
Performance Shares [Member]
Performance Shares [Member]
Restricted Stock [Member]
Restricted Stock [Member]
Stock Options [Member]
Stock Options [Member]
Equity Units [Member]
Equity Unit Purchase Agreements [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
Jointly Owned Electric Utility Plants [Abstract]
-- None. No documentation exists for this element. --
Jointly Owned Electric Utility Plants [Text Block]
Jointly Owned Electric Utility Plants [Text Block]
The entire disclosure on jointly owned electric utility plants.
Derivative [Table]
Derivative, by Nature [Axis]
Derivative, Name [Domain]
Futures contracts [Member]
Future [Member]
Forward Contracts [Member]
Option contracts [Member]
Options Held [Member]
Hedging Relationship [Axis]
Hedging Relationship [Domain]
Cash Flow Hedging [Member]
Derivative [Line Items]
Price Risk Derivatives [Abstract]
Percentage of projected natural gas usage hedged year one
Percentage Of Projected Natural Gas Usage Hedged Year One
Percentage of projected natural gas usage hedged for the year following the balance sheet date.
Percentage of projected natural gas usage hedged year two
Percentage Of Projected Natural Gas Usage Hedged Year Two
Percentage of projected natural gas usage hedged for the second year following the balance sheet date.
Percentage of expected on peak natural gas and natural gas equivalent purchased power price exposure hedged year one
Percentage Of Expected On Peak Natural Gas And Natural Gas Equivalent Purchased Power Price Exposure Hedged Year One
Percentage of expected on-peak natural gas and natural gas equivalent purchased power price exposure that is hedged for the year following the balance sheet date.
Percentage of expected on peak natural gas and natural gas equivalent purchased power price exposure hedged year two
Percentage Of Expected On Peak Natural Gas And Natural Gas Equivalent Purchased Power Price Exposure Hedged Year Two
Percentage of expected on-peak natural gas and natural gas equivalent purchased power price exposure that is hedged for the second year following the balance sheet date.
Percentage of expected on peak natural gas and natural gas equivalent purchased power price exposure hedged year three
Percentage of expected on peak natural gas and natural gas equivalent purchased power price exposure hedged year three
Percentage of projected natural gas usage hedged for the third year following the balance sheet date.
Notional Contract Amount
Derivative, Notional Amount
Fair Value
Derivative, Fair Value, Gross Amount Not Offset Against Collateral, Net
Common Stock [Member]
Retained Earnings [Member]
Treasury Stock [Member]
Accumulated Other Comprehensive Income (Loss) [Member]
Noncontrolling Interest [Member]
Other Consolidated Entities [Member]
Other Consolidated Entities [Member]
Other companies which are controlled, directly or indirectly, by the parent. The usual condition for control is ownership of a majority (over 50%) of the outstanding voting stock. The power to control may also exist with a lesser percentage of ownership, for example, by contract, lease, agreement with other stockholders or by court decree.
Beginning balance
Beginning balance (in shares)
Shares, Issued
Issuance of common stock
Stock Issued During Period, Value, New Issues
Issuance of common stock (in shares)
Stock Issued During Period, Shares, New Issues
Issuance of restricted common stock
Stock Issued During Period, Value, Share-based Compensation, Gross
Issuance of restricted common stock (in shares)
Stock Issued During Period, Shares, Share-based Compensation, Gross
Equity compensation expense, net of forfeitures
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs
Proceeds from Contributions from Parent
Unearned Compensation [Abstract]
Issuance of restricted common stock
Stock Issued During Period, Value, Restricted Stock Award, Gross
Forfeiture of restricted common stock
Stock Issued During Period, Value, Restricted Stock Award, Forfeitures
Compensation expense recognized
Adjustments to Additional Paid in Capital, Share-based Compensation, Restricted Stock Unit or Restricted Stock Award, Requisite Service Period Recognition
Stockholders' Equity, Other
Stockholders' Equity, Other
Loss on reissuance of treasury stock
Treasury Stock Reissued at Lower than Repurchase Price
Dividends:
Dividends [Abstract]
Common stock
Dividends, Common Stock, Cash
Preferred stock - at required rates
Dividends, Preferred Stock, Cash
Performance shares
Dividends, Share-based Compensation, Cash
Treasury shares acquired
Treasury Stock, Value, Acquired, Cost Method
Treasury shares acquired (in shares)
Treasury Stock, Shares, Acquired
Treasury shares reissued
Stock Issued During Period, Value, Treasury Stock Reissued
Treasury shares reissued (in shares)
Stock Issued During Period, Shares, Treasury Stock Reissued
Derivative hedging activity, net of tax
Change in unrecognized pension expense, net of tax
Net income attributable to noncontrolling interest
Distribution
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders
Ending balance
Ending balance (in shares)
Fair Value Disclosures [Abstract]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table]
Other Great Plains [Member]
Fair Value by Asset Class [Axis]
Asset Class [Axis]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, by Asset Class [Domain]
Fair Value by Asset Class [Domain]
Derivative Financial Instruments, Assets [Member]
Derivative Financial Instruments, Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value
Total realized/unrealized gains or (losses) included in non-operating income
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales
Settlements
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements
Balance at end of period
Total unrealized gains and (losses) included in non-operating income relating to assets and liabilities still on the consolidated balance sheet at period end
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income
Unrecorded Unconditional Purchase Obligation and Lease Commitments [Table]
Unrecorded Unconditional Purchase Obligation and Lease Commitments [Table]
Describes each unrecorded unconditional purchase obligation arrangement to purchase goods and services that extend over multiple periods, any assets pledged to secure payment, any lease commitments (capital or operating) and the fixed or determinable amount of payments due in each of the next five years and thereafter.
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]
Public Utilities, Inventory, Fuel [Member]
Public Utilities, Inventory, Fuel [Member]
Purchased Power [Member]
Purchased Power [Member]
Commitments for purchased power.
Capacity [Member]
Capacity [Member]
Non-regulated natural gas transportation [Member]
Non-regulated natural gas transportation [Member]
Commitments for non-regulated natural gas transportation.
La Cygne Environmental Project [Member]
La Cygne Environmental Project [Member]
Commitments related to the La Cygne Environmental Project.
Other purchase commitments [Member]
Other purchase commitments [Member]
Purchase commitments for other items not otherwise disclosed in the taxonomy.
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 Equipment under operating leases [Member]
property, plant equipment under operating leases [Member]
Information on property, plant and equipment used by the Company under operating leases.
Property, Plant and Equipment under capital leases [Member]
Property, Plant and Equipment under capital leases [Member]
Information on property, plant and equipment used by the Company under capital leases.
Supply Commitment [Axis]
Supply Commitment [Axis]
Supply Commitment Arrangement [Domain]
Supply Commitment Arrangement [Domain]
Supply Commitment [Member]
Supply Commitment [Member]
Reimbursement Commitments [Member]
Reimbursement commitments member [Member]
Commitments from others to reimburse the Company for leased property, plant or equipment.
Unrecorded Unconditional Purchase Obligations and Lease Commitments [Line Items]
Unrecorded Unconditional Purchase Obligation [Line Items]
Lease Expense [Abstract]
Leases [Abstract]
Lease expense
Operating Leases, Rent Expense, Net
Operating Leases [Abstract]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months
Operating Leases, Future Minimum Payments Due, Next Twelve Months
Operating Leases, Future Minimum Payments, Due in Two Years
Operating Leases, Future Minimum Payments, Due in Two Years
Operating Leases, Future Minimum Payments, Due in Three Years
Operating Leases, Future Minimum Payments, Due in Three Years
Operating Leases, Future Minimum Payments, Due in Four Years
Operating Leases, Future Minimum Payments, Due in Four Years
Operating Leases, Future Minimum Payments, Due in Five Years
Operating Leases, Future Minimum Payments, Due in Five Years
Operating Leases, Future Minimum Payments, Due Thereafter
Operating Leases, Future Minimum Payments, Due Thereafter
Operating Leases, Future Minimum Payments Due, Total
Operating Leases, Future Minimum Payments Due
Capital Leases [Abstract]
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Capital Leases, Future Minimum Payments Due, Next Twelve Months
Capital Leases, Future Minimum Payments Due, Next Twelve Months
Capital Leases, Future Minimum Payments Due in Two Years
Capital Leases, Future Minimum Payments Due in Two Years
Capital Leases, Future Minimum Payments Due in Three Years
Capital Leases, Future Minimum Payments Due in Three Years
Capital Leases, Future Minimum Payments Due in Four Years
Capital Leases, Future Minimum Payments Due in Four Years
Capital Leases, Future Minimum Payments Due in Five Years
Capital Leases, Future Minimum Payments Due in Five Years
Capital Leases, Future Minimum Payments Due Thereafter
Capital Leases, Future Minimum Payments Due Thereafter
Capital Leases, Future Minimum Payments Due, Total
Capital Leases, Future Minimum Payments Due
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, Total
Unrecorded Unconditional Purchase Obligation
Total Commitments [Abstract]
Total Commitments [Abstract]
Total Commitments [Abstract]
Total Commitments, Due in Next Twelve Months
Total Commitments, Due in Next Twelve Months
The aggregate amount of operating and capital lease payments and unconditional purchase obligations due in the twelve months after the balance sheet date.
Total Commitments, Due within Two Years
Total Commitments, Due within Two Years
The aggregate amount of operating and capital lease payments and unconditional purchase obligations due in the second year after the balance sheet date.
Total Commitments, Due within Three Years
Total Commitments, Due within Three Years
The aggregate amount of operating and capital lease payments and unconditional purchase obligations due in the third year after the balance sheet date.
Total Commitments, Due within Four Years
Total Commitments, Due within Four Years
The aggregate amount of operating and capital lease payments and unconditional purchase obligations due in the fourth year after the balance sheet date.
Total Commitments, Due within Five Years
Total Commitments, Due within Five Years
The aggregate amount of operating and capital lease payments and unconditional purchase obligations due in the fifth year after the balance sheet date.
Total Commitments, Due Thereafter
Total Commitments, Due Thereafter
The aggregate amount of operating and capital lease payments and unconditional purchase obligations due following the fifth year after the balance sheet date.
Total Commitments Due
Total Commitments Due
The aggregate amount of operating and capital lease payments and unconditional purchase obligations due.
Reimbursement by Other Owners per Year (2013 to 2015)
Reimbursement by Other Owners per Year (2013 to 2015)
Reimbursement by other owners to KCP and L for leased property, plant, or equipment per year from 2013 to 2015.
Reimbursements by Other Owners per Year (2016 to 2025)
Reimbursements by Other Owners per Year (2016 to 2025)
Reimbursement by other owners to KCP and L for leased property, plant, or equipment during 2016 to 2025, per year.
Reimbursements by Other Owners Total
Reimbursements by Other Owners Total
Total reimbursement by other owners to KCP and L for leased property, plant, or equipment.
Capacity Sales Agreements in 2013
Capacity Sales Agreements in 2013
Capacity sales agreements entered into by KCP and L for 2013.
Capacity Sales Agreements per Year (2014 to 2016)
Capacity Sales Agreements per Year (2014 to 2016)
Capacity sales agreements entered into by KCP and L per year from 2014 to 2016.
Regulated Operations [Abstract]
Regulatory Proceedings [Table]
Regulatory Proceedings [Axis]
This element represents summary of the initial filing information in currently pending requests for retail rate increases.
Regulatory Proceedings [Domain]
Provides general categories related to initial filing information in currently pending requests for retail rate increases.
Rate jurisdiction - Kansas [Member]
Rate Jurisdiction Kansas [Member]
Information related to the State Corporation Commission of the State of Kansas .
Rate jurisdiction - Missouri [Member]
Rate Jurisdiction Missouri [Member]
Information related to the Public Service Commission of the State of Missouri.
Rate jurisdiction - St. Joseph Light and Power division [Member]
Rate Jurisdiction St Joseph Light And Power Division [Member]
Information related to the St. Joseph Light and Power division.
Rate jurisdiction - Missouri Public Service division [Member]
Rate Jurisdiction Missouri Public Service Division [Member]
Information related to Missouri public service division
Mortgages [Member]
Mortgages [Member]
Corporate Debt Securities [Member]
Corporate Debt Securities [Member]
Loans Payable [Member]
Loans Payable [Member]
Regulatory Proceedings [Line Items]
Annual revenue increase, requested
Annual Revenue Increase
The annual increase in revenue from retail rate increase related to pending request filed with the state.
Revised annual revenue increase, requested
Revised annual revenue increase
The revised annual increase in revenue from retail rate increase related to pending request filed with the state.
Return on equity, requested (in hundredths)
Return on Equity
The amount of net income returned as a percentage of shareholders equity as requested by the company in the pending rate case filed with the state. Return on equity measures a corporation's profitability by revealing how much profit a company generates with the money shareholders have invested.
Revised return on equity, requested (in hundredths)
Revised return on equity (in hundredths)
Revised return on equity as requested by the company in the pending rate case filed with the state.
Rate-making equity ratio, requested (in hundredths)
Rate-Making Equity Ratio
Discloses the equity percentage of total capitalization used in the rate making process.
Annual revenue increase authorized
Annual revenue increase authorized
The annual increase in revenue from retail rate increase authorized by the state.
Return on equity, approved (in hundredths)
Return on equity, approved (in hundredths)
The approved amount of net income returned as a percentage of shareholders equity. Return on equity measures a corporation's profitability by revealing how much profit a company generates with the money shareholders have invested.
Ratemaking equity ratio, approved (in hundredths)
Ratemaking equity ratio, approved (in hundredths)
The approved equity percentage of total capitalization used in the rate making process.
Rate making equity ratio after including other comprehensive income, approved
Rate making equity ratio after including other comprehensive income, approved
The approved equity percentage (including other comprehensive income) of total capitalization used in the rate making process.
Supplemental Cash Flow Elements [Abstract]
Accounts receivable pledged as collateral
Collateralized note payable
Receivables
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.
Fuel inventories
Increase (Decrease) in Fuel Inventories
Materials and supplies
Increase (Decrease) in Raw Materials, Packaging Materials and Supplies Inventories
Accounts payable
Increase (Decrease) in Accounts Payable
Deferred refueling outage costs
Increase Decrease In Deferred Refueling Outage Costs
The increase (decrease) in deferred refueling outage costs.
Fuel recovery mechanism
Increase (Decrease) in over (under) Energy Recovery
Pension and post-retirement benefit obligations
Increase (Decrease) in Pension and Postretirement Obligations
Increase (Decrease) in Allowance for Equity Funds Used During Construction
Increase (Decrease) in Allowance for Equity Funds Used During Construction
Write down of affordable housing investments
Write down of affordable housing investments
Write down of affordable housing investments during the period.
Iatan Nos. 1 and 2 impact of disallowed construction costs
Impact of disallowed construction costs
Impact of disallowed construction costs in Iatan Nos. 1 and 2.
Uncertain tax positions
IncreaseDecreaseInUncertainTaxPositions
The increase (decrease) during the reporting period in the value of uncertain tax positions.
Total other operating activities
Total Other Operating Activities
Total of increase or decrease in operating capital plus other cash or noncash adjustments to reconcile net income to cash provided by (used in) operating activities.
Cash paid during the period:
Supplemental Cash Flow Information [Abstract]
Interest Paid, Net
Interest Paid, Net
Income Taxes Paid
Income Taxes Paid
Non-cash investing activities:
Other Noncash Investing and Financing Items [Abstract]
Liabilities assumed for capital expenditures
Construction in Progress Expenditures Incurred but Not yet Paid
Schedule of Public Utility Property, Plant, and Equipment [Table Text Block]
Schedule of Public Utility Property, Plant, and Equipment [Table Text Block]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]
Gain Contingencies [Table]
Gain Contingencies, Nature [Axis]
Gain Contingency, Nature [Domain]
Positive Outcome of Litigation [Member]
Subsequent Event Type [Axis]
Subsequent Event Type [Axis]
Subsequent Event Type [Domain]
Subsequent Event Type [Domain]
Subsequent Event [Member]
Subsequent Event [Member]
Gain Contingencies [Line Items]
Amount of pending claims against the United States in the U.S. Court
Gain Contingency, Unrecorded Amount
Amount awarded but subject to appeal
Amount Awarded But Subject To Appeal
Pertains to the amount awarded, but subject to appeal, by the U.S. Court of Federal Claims for damages from the government's failure to begin accepting spent nuclear fuel for disposal as required by the Nuclear Waste Policy Act of 1982.
Additional amount awarded upon appeal
Additional amount awarded upon appeal
Pertains to the additional amount awarded, upon appeal, by the U.S. Court of Appeals for the Federal Circuit for damages from the government's failure to begin accepting spent nuclear fuel for disposal as required by the Nuclear Waste Policy Act of 1982.
Subsequent Event Amount
Subsequent Event, Amount
Subsequent Event Description
Subsequent Event, Description
Statement of Financial Position (Parenthetical) [Abstract]
Statement of Financial Position (Parenthetical) [Abstract]
Preferred Stock [Member]
Common Stock, Shares Authorized
Common Stock, Shares Authorized
Common Stock, Shares, Issued
Common Stock, Shares, Issued
Treasury Stock, Shares
Treasury Stock, Shares
Preferred Stock, Par or Stated Value Per Share
Preferred Stock, Par or Stated Value Per Share
Preferred Stock, Dividend Rate, Percentage
Preferred Stock, Dividend Rate, Percentage
Preferred Stock, Shares Issued
Preferred Stock, Shares Issued
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]
Changes in nuclear decommissioning trust fund
Changes in nuclear decommissioning trust fund [Table Text Block]
A tabular disclosure that summarizes the change in nuclear decommissioning trust fund during the period.
Detail of assets held in nuclear decommissioning trust fund
Detail of assets held in nuclear decommissioning trust fund [Table Text Block]
This item represents the entire disclosure related to nuclear decommissioning trust fund which consist of all investments in certain debt and equity securities (and other assets). The nuclear decommission fund is maintained to pay for the costs of decontaminating and decommissioning of facilities through collection of revenues derived from utility assessments and government appropriations.
Gains and losses from the sale of securities by the nuclear decommissioning trust fund
Nuclear Decomissioning Trust fund Sale of Securities Gains Losses [Table Text Block]
This item represents the entire disclosure related to realized gain or loss on sale of securities related to nuclear decommissioning trust fund.
Nuclear Plant Decommissioning Costs
Nuclear Plant Decommissioning Costs [Table Text Block]
A tabular disclosure of current and future decommissioning costs related to nuclear plants.
Goodwill
Schedule of Finite-Lived Intangible Assets [Table]
Schedule of Finite-Lived Intangible Assets [Table]
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Computer Software, Intangible Asset [Member]
Computer Software, Intangible Asset [Member]
Asset Improvements [Member]
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross
Finite-Lived Intangible Assets, Gross
Finite-Lived Intangible Assets, Accumulated Amortization
Finite-Lived Intangible Assets, Accumulated Amortization
Amortization of Intangible Assets
Amortization of Intangible Assets
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months
Finite-Lived Intangible Assets, Amortization Expense, Year Two
Finite-Lived Intangible Assets, Amortization Expense, Year Two
Finite-Lived Intangible Assets, Amortization Expense, Year Three
Finite-Lived Intangible Assets, Amortization Expense, Year Three
Finite-Lived Intangible Assets, Amortization Expense, Year Four
Finite-Lived Intangible Assets, Amortization Expense, Year Four
Finite-Lived Intangible Assets, Amortization Expense, Year Five
Finite-Lived Intangible Assets, Amortization Expense, Year Five
Subsequent Event [Table]
Subsequent Event [Table]
Dividend Declared [Member]
Dividend Declared [Member]
Subsequent Event [Line Items]
Subsequent Event [Line Items]
Dividends Declared [Abstract]
Dividends Declared [Abstract]
Subsequent Event, Date
Subsequent Event, Date
Subsequent per common share amount (in dollars per share)
Subsequent Event Amount Per Share
Reflects the per common share amount of dividends declared subsequent to year end.
Stockholders' Equity Note [Abstract]
Common Shareholders' Equity
Stockholders' Equity Note Disclosure [Text Block]
Derivative [Table]
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months
Fair value of assets and liabilities
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Unobservable inputs reconciliation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
Entity information [Abstract]
Entity information for DEI
Entity Registrant Name
Entity Central Index Key
Current Fiscal Year End Date
Entity Well-known Seasoned Issuer
Entity Voluntary Filers
Entity Current Reporting Status
Entity Filer Category
Entity Public Float
Entity Common Stock, Shares Outstanding
Document Fiscal Year Focus
Document Fiscal Period Focus
Document Type
Amendment Flag
Document Period End Date
Deferred Income Taxes Disclosure [Abstract]
Deferred Income Taxes Disclosure [Abstract]
Components of Deferred Tax Assets and Liabilities [Abstract]
Components of Deferred Tax Assets and Liabilities [Abstract]
Deferred Tax Assets (Liabilities), Net of Valuation Allowance, Current Classification [Abstract]
Deferred Tax Assets, Net of Valuation Allowance, Current Classification [Abstract]
Net operating loss carryforward, current
Deferred tax assets, operating loss carryforwards, current
The sum of the tax effects as of the balance sheet date of the amount of excesses of tax deductions over gross income in a year which can be used on the tax returns within the next twelve months to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset.
Deferred tax assets, other current
Deferred tax assets, other, current
The tax effect as of the balance sheet date of the amount of estimated future tax deductions arising from other temporary differences not otherwise specified in the taxonomy.
Deferred Tax Assets, Gross, Current
Deferred Tax Assets, Gross, Current
Valuation allowance, current
Deferred Tax Assets, Valuation Allowance, Current
Deferred Tax Assets (Liabilities), Net, Current
Deferred Tax Assets, Net, Current
Deferred Tax Assets (Liabilities), Net of Valuation Allowance, Noncurrent Classification [Abstract]
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent Classification [Abstract]
Plant related
Deferred Tax Liabilities, Property, Plant and Equipment
Income taxes on future regulatory recoveries
Deferred tax liability income taxes on future regulatory recoveries
The amount as of the balance sheet date of the estimated future tax effects attributable to future regulatory recoveries.
Derivative instruments
Deferred Tax Assets, Derivative Instruments
Pension and post-retirement benefits
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Pensions
SO2 emission allowance sales
Deferred tax asset SO2 emission allowance sales
The amount as of the balance sheet date of the estimated future tax effects attributable to the sales of SO 2 emission allowances.
Fuel recovery mechanisms
Deferred tax liabilities fuel recovery mechanisms
The amount as of the balance sheet date of the estimated future tax effects attributable to fuel clause adjustments.
Transition costs
Deferred tax liabilities transition costs
The amount as of the balance sheet date of the estimated future tax effects attributable to transition costs.
Tax credit carryforwards
Deferred Tax Assets, Tax Credit Carryforwards
Long-term debt fair value adjustment
Deferred Tax Liabilities, Financing Arrangements
Customer demand programs
Deferred tax liabilities customer demand programs
The amount as of the balance sheet date of the estimated future tax effects attributable to customer demand programs.
Net operating loss carryforward, noncurrent
Deferred tax asset, net operating loss carryforward, noncurrent
The sum of the tax effects as of the balance sheet date of the amount of excesses of tax deductions over gross income in a year which cannot be used on the tax returns in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset.
Deferred tax assets, other noncurrent
Deferred tax assets other noncurrent
The tax effect as of the balance sheet date of the amount of estimated future tax deductions arising from other temporary differences not otherwise specified in the taxonomy.
Deferred Tax Assets, Gross, Noncurrent
Deferred Tax Assets, Gross, Noncurrent
Valuation allowance, noncurrent
Deferred Tax Assets, Valuation Allowance, Noncurrent
Deferred Tax Assets (Liabilities), Net, Noncurrent
Deferred Tax Assets, Net, Noncurrent
Deferred Tax Assets (Liabilities), Net
Deferred Tax Assets, Net
Deferred Tax Assets (Liabilities), Gross [Abstract]
Deferred Tax Assets, Gross [Abstract]
Deferred Tax Assets, Gross
Deferred Tax Assets, Gross
Deferred Tax Liabilities, Gross
Deferred Tax Liabilities, Gross
Deferred Tax Assets, Net
Valuation Allowance [Abstract]
Valuation Allowance [Abstract]
Valuation Allowance, Deferred Tax Asset, Change in Amount
Valuation Allowance, Deferred Tax Asset, Change in Amount
Valuation Allowance, Deferred Tax Asset, Explanation of Change
Valuation Allowance, Deferred Tax Asset, Explanation of Change
Estimates Of Environmental Financial Impact And Related Issues [Table]
Westar Energy Inc [Member]
Westar Energy Inc [Member]
Utility operating in Kansas.
Jointly Owned Utility Plant, by Plant Name [Axis]
Jointly Owned Utility Plant, by Plant Name [Axis]
Jointly owned utiltiy plant, by plant name.
Jointly Owned Utility Plant, by Plant Name [Domain]
Jointly Owned Utility Plant, by Plant Name [Domain]
Jointly owned utiltiy plant, by plant name.
LaCygne Station [Member]
Information on the LaCygne Station.
Jeffrey Units Nos 1 and 2 [Member]
Jointly owned plant operating in Kansas.
LaCygne Station Environmental Retrofits [Member]
Information on LaCygne Station environmental retrofits.
Estimates Of Environmental Financial Impact And Related Issues [Line Items]
Air and Climate Change [Abstract]
Current estimate of capital expenditures
Represents the current estimate of capital expenditures (exclusive of AFUDC and property taxes) required to comply with the currently effective Clean Air Interstate Rule CAIR, the replacement to CAIR or the Cross-State Air Pollution Rule, and with the best available retrofit technology rule, the SO2 national ambient air quality standard, the industrial boiler rule and proposed maximum achievable control technology standards for mercury and other hazardous air pollutant emissions.
Cash capital expenditures incurred for La Cygne environmental project
Cash Capital Expenditures Incurred for La Cygne Environmental Project
The amount of cash capital expenditures that have been incurred since commencement of the La Cygne environmental project and are included in the Company's total estimate of capital expenditures to comply with environmental regulations.
Clean Air Interstate Rule (CAIR) and Cross-State Air Pollution Rule (CSAPR) [Abstract]
Clean Air Interstate Rule and Transport Rule [Abstract]
KCPL share of predetermination request for environmental equipment required at LaCygne Station to comply with BART
Kcpl Share Of Predetermination Request For Environmental Equipment Required At Lacygne Station To Comply With Bart
KCPL's share of the amount of the predetermination request in Kansas for environmental equipment required at LaCygne Station to comply with BART.
Number Of States Required To Reduce Emissions Under Cair
Number Of States Required To Reduce Emissions Under Cair
Represents the number of states required to reduce emissions of SO2 and NOX under the CAIR, including Missouri.
Mercury and Other Hazardous Air Pollutant Emissions [Abstract]
Capacity of electric steam generating units that fall under MACT standards (in megawatts)
Capacity of electric steam generating units that fall under MACT standards in mw
New MACT rules will apply to all new or existing coal-fired electric generating units with a capacity equal to or greater than this amount.
Climate Change [Abstract]
CO2 produced per year (in tons)
Estimated Number Of Tons Of Co2 Produced Per Year
Represents the estimated number of tons of CO2 produced each year based on current generation capacity.
Minimum required renewable energy generation capacity percentage in Kansas by 2011
Minimum Percentage Of Kansas Renewable Energy Generation Capacity Based On Three Year Average Peak Retail Demand By Year Two
Represents the renewable energy generation capacity based on a three-year average of Kansas peak retail demand required to be in place by 2011. This law was passed in 2009 and applies to all Kansas public electric utilities, including KCPL.
Minimum required renewable energy generation capacity percentage in Kansas by 2016
Minimum Percentage Of Kansas Renewable Energy Generation Capacity Based On Three Year Average Peak Retail Demand By Year Seven
Represents the renewable energy generation capacity based on a three-year average of Kansas peak retail demand required to be in place by 2016. This law was passed in 2009 and applies to all Kansas public electric utilities, including KCPL.
Minimum required renewable energy generation capacity percentage in Kansas by 2020
Minimum Percentage Of Kansas Renewable Energy Generation Capacity Based On Three Year Average Peak Retail Demand By Year Eleven
Represents the renewable energy generation capacity based on a three-year average of Kansas peak retail demand required to be in place by 2020. This law was passed in 2009 and applies to all Kansas public electric utilities, including KCPL.
Minimum required renewable energy generation capacity percentage in Missouri by 2011
Minimum Percentage Of Missouri Electricity To Come From Renewable Resources For Retail Customers By Year Three
Represents the percentage of electricity provided by Missouri investor-owned utilities (including KCPL and GMO) to their Missouri retail customers required to come from renewable resources by 2011, pursuant to a law passed in 2008.
Minimum required renewable energy generation capacity percentage in Missouri by 2014
Minimum Percentage Of Missouri Electricity To Come From Renewable Resources For Retail Customers By Year Six
Represents the percentage of electricity provided by Missouri investor-owned utilities (including KCPL and GMO) to their Missouri retail customers required to come from renewable resources by 2014, pursuant to a law passed in 2008.
Minimum required renewable energy generation capacity percentage in Missouri by 2018
Minimum Percentage Of Missouri Electricity To Come From Renewable Resources For Retail Customers By Year Ten
Represents the percentage of electricity provided by Missouri investor-owned utilities (including KCPL and GMO) to their Missouri retail customers required to come from renewable resources by 2018, pursuant to a law passed in 2008.
Minimum required renewable energy generation capacity percentage in Missouri by 2021
Minimum Percentage Of Missouri Electricity To Come From Renewable Resources For Retail Customers By Year Thirteen
Represents the percentage of electricity provided by Missouri investor-owned utilities (including KCPL and GMO) to their Missouri retail customers required to come from renewable resources by 2021, pursuant to a law passed in 2008.
Estimated electricity required to come from solar resources (in megawatts)
Estimated Number Of Megawatts Of Missouri Electricity To Come From Solar Resources
Represents the company-specific estimated megawatts of electricity required to be provided by KCPL and GMO to their Missouri retail customers from solar resources by 2011, pursuant to a law passed in 2008.
SO2 National Ambient Air Quality Standard (NAAQS) [Abstract]
So2 National Ambient Air Quality Standard [Abstract]
Primary one-hour sulfur dioxide standard, as revised June 2010 (in parts per million)
Revised Parts Per Million For Sulphur Dioxide Established For Primary Standard
Represents the primary one-hour sulfur dioxide standard as revised by the Environmental Protection Agency in June 2010 to replace the exisiting 24-hour and one-year standards.
Primary twenty-four hour sulfur dioxide standard, prior to June 2010 (in parts per million)
Revoked Parts Per Million For Sulphur Dioxide For Primary Standard Over1 Day
Represents the primary twenty-four hour sulfur dioxide standard revoked by the Environmental Protection Agency in June 2010.
Primary one-year sulfur dioxide standard, prior to June 2010 (in parts per million)
Revoked Parts Per Million For Sulphur Dioxide For Primary Standard Over1 Year
Represents the primary one-year sulfur dioxide standard revoked by the Environmental Protection Agency in June 2010.
Remediation [Abstract]
Remediation Abstract
Accrued environmental remediation expenses
Accrual for Environmental Loss Contingencies
Amount accrued for future investigation remediation and of GMO retained liabilities
Accrual For Future Investigation Environmental Remediation And Retained Liabilities Expense
Total costs accrued as of the balance sheet date for the future investigation and remediation of certain additional GMO identified MGP sites, PCB sites and retained liabilities.
Estimated amount of insurance proceeds available to cover qualified remediation expenses
Estimated Dollar Amount Of Available Insurance Proceeds To Cover Qualified Remediation Expense
Represents the estimated amount of insurance proceeds available, less an annual deductible, to GMO cover qualified MGP remediation expenses.
Best Available Retrofit Technology Rule (BART) [Abstract]
Best Available Retrofit Technology Rule [Abstract]
Predetermination request for environmental equipment required at LaCygne Station to comply with BART
The amount of the predetermination request in Kansas for environmental equipment required at LaCygne Station to comply with BART.
Entity's ownership percentage in facility (in hundredths)
Jointly Owned Utility Plant, Proportionate Ownership Share
New Source Review [Abstract]
Estimated cost to install a selective catalytic reduction system at Jeffrey Energy Center pursuant to a settlement agreement
Cost To Install Selective Catalytic Reduction System
Represents the estimated cost to install a selective catalytic reduction system at Jeffrey Energy Center pursuant to a settlement agreement related to Westar Energy, Incorporated's alleged Clean Air Act violations.
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Additions
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
Asset Retirement Obligation
Asset Retirement Obligation
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Deferred Compensation Arrangement with Individual, Share-based Payments [Table]
Schedule of Deferred Compensation Arrangement with Individual, Share-based Payments [Table]
Title of Individual [Axis]
Title of Individual [Axis]
Title of Individual with Relationship to Entity [Domain]
Title of Individual with Relationship to Entity [Domain]
Director [Member]
Director [Member]
Type of Deferred Compensation [Axis]
Type of Deferred Compensation [Axis]
Type of Deferred Compensation, All Types [Domain]
Type of Deferred Compensation, All Types [Domain]
Director Deferred Share Units [Member]
Deferred Compensation, Share-based Payments [Member]
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Director deferred share units [Roll Forward]
Director deferred share units [Roll Forward]
A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.
Director deferred share units, beginning balance (in shares)
Deferred compensation arrangement with individual shares outstanding
The number of director deferred share units outstanding at the balance sheet date.
Director deferred share units, issued (in shares)
Deferred Compensation Arrangement with Individual, Shares Issued
Director deferred share units, ending balance (in shares)
Weighted-average grant date fair value, director deferred share units, beginning balance (in dollars per share)
Weighted-average grant date fair value, director deferred share units, shares outstanding
The weighted-average grant date fair value of director deferred share units outstanding.
Weighted-average grant date fair value, director deferred share units, issued (in dollars per share)
Weighted average grant date fair value director deferred share units shares issued during period
The weighted average grant date fair value of director deferred share units issued during the period.
Weighted-average grant date fair value, director deferred share units, ending balance (in dollars per share)
Fair Value Measurements
Fair Value Disclosures [Text Block]
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Schedule of Change in Asset Retirement Obligation [Table Text Block]
Debt Disclosure [Abstract]
Long-Term Debt
Long-term Debt [Text Block]
Asset Retirement Obligations [Text Block]
Asset Retirement Obligation Disclosure [Text Block]
Investments in nuclear decommissioning trust fund [Table]
Schedule of Available-for-sale Securities [Table]
Investments in decommissioning trust fund [Axis]
Major Types of Debt and Equity Securities [Axis]
Investments in decommissioning trust fund [Domain]
Major Types of Debt and Equity Securities [Domain]
Equity Securities [Member]
Debt Securities [Member]
Other Securities [Member]
This category includes information about securities other than equity or debt type securities that will be realized in a short period of time, usually less than one year or the normal operating cycle, whichever is longer.
Investments in decommissioning trust fund [Line Items]
Schedule of Available-for-sale Securities [Line Items]
Cost Basis
Available-for-sale Securities, Amortized Cost Basis
Gross Unrealized Gains
Available-for-sale Securities, Gross Unrealized Gains
Gross Unrealized Losses
Available-for-sale Securities, Gross Unrealized Losses
Fair Value, Nuclear decommissioning trust fund
Weighted average maturity of debt securities (in years)
Weighted Average Maturity Of Debt Securities
This represents the weighted average number of years when the debt securities held in the decommissioning trust fund are scheduled to be fully repaid.
Realized Gains on investments in decommissioning trust fund
Available-for-sale Securities, Gross Realized Gains
Realized Losses on investments in decommissioning trust fund
Available-for-sale Securities, Gross Realized Losses
Uncertain Tax Positions Disclosure [Abstract]
Uncertain Tax Positions Disclosure [Abstract]
Income Tax Contingency [Table]
Income Tax Contingency [Table]
Uncertain Tax Positions [Line Items]
Income Tax Contingency [Line Items]
Amount expected to impact the effective tax rate if recognized
Unrecognized Tax Benefits that Would Impact Effective Tax Rate
Unrecognized Tax Benefits, Period Increase (Decrease)
Unrecognized Tax Benefits, Period Increase (Decrease)
Unrecognized tax benefit increase (decrease) related to former GMO non-regulated operations
Unrecognized tax benefit increase (decrease) related to former GMO non-regulated operations
Increase or decrease in unrecognized tax benefits related to former GMO non-regulated operations.
Unrecognized tax benefit increase (decrease) related to audit settlements
Unrecognized tax benefit increase (decrease) related to audit settlements
Represents the unrecognized tax benefit impact of audit settlements
Deferred income tax liability increase (decrease) related to audit settlements
Deferred income tax liability impact of audit settlements
Represents the deferred income tax liability increase (decrease) related to of audit settlements
Increase (decrease) in net income related to settlement of tax audit
Increase (decrease) in net income related to settlement of tax audit
The increase, (decrease) in net income related to the settlement of a federal tax audit.
Uncertain tax position increase (decrease) related to temporary differences
Uncertain tax position increase decrease related to temporary differences
Uncertain tax position increase decrease related to temporary differences
Accrued interest related to unrecognized tax benefits
Unrecognized Tax Benefits, Interest on Income Taxes Accrued
Accrued penalties with respect to unrecognized tax benefits
Unrecognized Tax Benefits, Income Tax Penalties Accrued
Interest expense related to unrecognized tax benefits
Unrecognized Tax Benefits, Interest on Income Taxes Expense
Amount of unrecognized tax benefits may be recognized in the next twelve months due to statute expirations or settlement agreements with tax authorities
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period
Unrecognized Tax Benefits
Additions for current year tax positions
Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions
Additions for prior year tax positions
Unrecognized Tax Benefits, Increases Resulting from Prior Period Tax Positions
Reductions for prior year tax positions
Unrecognized Tax Benefits, Decreases Resulting from Prior Period Tax Positions
Settlements
Unrecognized Tax Benefits, Decreases Resulting from Settlements with Taxing Authorities
Statute expirations
Unrecognized Tax Benefits, Reductions Resulting from Lapse of Applicable Statute of Limitations
Foreign currency translation adjustments
Unrecognized Tax Benefits, Increases Resulting from Foreign Currency Translation
Balance at end of period
Schedule of Rent Expense [Table Text Block]
Lease and purchase commitments
Unrecorded Unconditional Purchase Obligations and Lease Commitments [Table Text Block]
Tabular disclosure of unconditional purchase obligations and lease commitments that are not recognized as liabilities on the balance sheet.
Schedule of Long-term Debt Instruments [Table]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Domain]
Secured Debt [Member]
Secured Debt [Member]
Environmental Improvement Revenue Refunding Bonds [Member]
Environmental Improvement Revenue Refunding Bonds [Member]
Environmental improvement revenue refunding bonds payable.
GMO First Mortgage Bonds [Member]
A loan to finance the purchase of real estate where the lender has a lien on the property as collateral for the loan.
GMO Pollution Control Bonds [Member]
GMO Pollution Control Bonds.
GMO Senior Notes [Member]
GMO Senior Notes.
GMO Medium Term Notes [Member]
A borrowing supported by a written promise to pay an obligation.
Other Long-Term Debt [Member]
Other Debt [Member]
A borrowing supported by a written promise to pay an obligation.
Great Plains Energy Senior Notes [Member]
Great Plains Energy Senior Notes.
Great Plains Energy Equity Units Subordinated Notes [Member]
Great Plains Energy Equity Units Subordinated Notes.
Debt Instrument [Axis]
Debt Instrument, Name [Domain]
General Mortgage bonds EIRR due 2015-2035 [Member]
General Mortgage bonds EIRR due 2015-2035 [Member]
General Mortgage bonds EIRR due 2012-2035.
General Mortgage bonds Series 2009 due 2019 [Member]
General Mortgage bonds Series 2009 due 2019 [Member]
General Mortgage bonds Series 2009 due 2019.
General Mortgage bonds EIRR series 2005 due 2035 [Member]
General Mortgage bonds EIRR series 2005 due 2035 [Member]
General Mortgage bonds EIRR series 2005 due 2035.
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.
Senior notes due 2017 KCPL [Member]
Senior notes due 2017 KCPL [Member]
Senior notes due 2017 KCPL.
Senior notes due 2018 KCPL [Member]
Senior notes due 2018 KCPL [Member]
Senior notes due 2018 KCPL.
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.
EIRR bonds 4.90 percent Series 2008
Eirr Bonds 490 Percent Series 2008 [Member]
4.9 percent EIRR bonds due 2038.
First mortgage bonds due 2013-2021 [Member]
First Mortgage Bonds Due20132021 Member
First mortgage bonds due 2013-2021.
Pollution control bonds SJLP due 2013 [Member]
Pollution control bonds SJLP due 2013 [Member]
Pollution control bonds SJLP due 2013.
Pollution control bonds Wamego Series 1996 due 2026 [Member]
Pollution control bonds Wamego Series 1996 due 2026 [Member]
Pollution control bonds Wamego Series 1996 due 2026.
Pollution control bonds state environmental 1993 due 2028 [Member]
Pollution control bonds state environmental 1993 due 2028 [Member]
Pollution control bonds state environmental 1993 due 2028.
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 11.875 percent series due 2012 [Member]
Senior Notes 11875 Percent Series Due 2012 [Member]
Senior notes 11.875 percent series due 2012.
Fair value adjustment [Member]
Fair value adjustment [Member]
Fair value adjustment.
Medium term notes 7.16 percent series due 2013 [Member]
Medium Term Notes 716 Percent Series Due 2013 [Member]
Medium term notes 7.16 percent series due 2013.
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
Senor notes due 2013 [Member]
Senor notes due 2013.
Senior notes due 2017 [Member]
Senior notes due 2017.
Senior Notes Due 2021 [Member]
Senior Notes Due 2021.
Senior Notes Due 2022 [Member]
Senior Notes Due 2022 [Member]
Senior Notes Due 2022.
Equity Units Subordinated Notes [Member]
Equity Units Subordinated Notes Member
Equity Units subordinated notes.
General Mortgage bonds Series 2007A-1 due 2035 [Member]
General Mortgage bonds Series 2007A-1 due 2035 [Member]
General Mortgage bonds Series 2007A-1 due 2035.
General Mortgage bonds EIRR series 2007A-2 due 2035 [Member]
General Mortgage bonds EIRR series 2007A-2 due 2035 [Member]
General Mortgage bonds EIRR series 2007A-2 due 2035.
Secured 1992 Series EIRR Bonds [Member]
Secured 1992 Series EIRR Bonds [Member]
Secured 1992 Series EIRR Bonds [Member]
Secured Series 1993a And 1993b Eirr Bonds Member
Secured Series 1993a And 1993b Eirr Bonds Member
Secured Series 1993A and 1993B EIRR bonds [Member]
Secured EIRR Bonds Series 2005 [Member]
Secured EIRR Bonds Series 2005 [Member]
Secured EIRR Bonds Series 2005 [Member]
Unsecured EIRR Bonds Series 2005 [Member]
Unsecured EIRR Bonds Series 2005 [Member]
Unsecured EIRR Bonds Series 2005 [Member]
Debt Instrument [Line Items]
Principal outstanding
Long-term Debt, Gross
Amortization expense related to fair value adjustment
Amortization expense related to fair value adjustment
Amortization expense related to the fair value adjustment.
Debt Instrument, Maturity Date
Debt Instrument, Maturity Date
Current maturities
Unamortized discount
Debt Instrument, Unamortized Discount
Unarmortized discount and premium, net
Debt Instrument, Unamortized Discount (Premium), Net
Long-term debt excluding current maturities
Debt Instrument Maturity Date Range Start
Debt Instrument, Maturity Date Range, Start
Debt Instrument Maturity Date Range End
Debt Instrument, Maturity Date Range, End
Interest rates (in hundredths)
Debt Instrument, Interest Rate, Stated Percentage
Long-term Debt, Weighted Average Interest Rate
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 at Period End
Bonds purchased in lieu of redemption
Environmental Improvement Revenue Refunding bonds that were purchased rather than remarketed given the poor conditions in the tax-exempt market.
Amortization of Financing Costs
Amortization of Financing Costs
KCPL Municipal Bond Insurance Policies [Abstract]
KCPL Municipal Bond Insurance Policies [Abstract]
KCPL Municipal Bond Insurance Policies [Abstract]
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 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.
Debt Instrument, Covenant Compliance
Debt Instrument, Covenant Compliance
Proportion of secured debt to total indebtedness maximum (in hundredths)
Proportion of secured debt to total indebtedness 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 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.
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.
Purchase Contracts Settled Early
Purchase Contracts Settled Early
Amount of purchase contracts that were settled early and did not participate in the remarketing of the Equity Units Subordinated Notes.
Number of outstanding Equity Units at settlement (in millions of units)
Number of outstanding Equity Units at settlement (in number of units)
Number of outstanding Equity Units at the settlement date of June 15, 2012.
Number of common shares issued in settlement of purchase contracts (in millions of shares)
Number of common shares issued in settlement of purchase contracts (in millions of shares)
Number of common shares issued at the settlement rate in settlement of the Equity Unit purchase contracts on June 15, 2012.
Settlement rate (in shares)
Settlement rate (in shares)
The ratio applied to the Equity Unit purchase contract for purposes of determining the number of shares of the equity security into which the purchase contract will be converted.
Applicable market value (in dollars per share)
Applicable market value
The applicable market value used to determine the settlement rate applied to the Equity Unit purchase contracts.
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
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]
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]
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]
Schedule of Deferred Compensation Arrangement with Individual, Share-based Payments [Table Text Block]
Regulatory Matters [Abstract]
Regulatory Matters [Abstract]
Schedule of Regulatory Assets [Table]
Schedule of Regulatory Assets [Table]
Regulatory Asset [Axis]
Regulatory Asset [Axis]
Regulatory Asset [Domain]
Regulatory Asset [Domain]
Taxes recoverable through future rates [Member]
Deferred Income Tax Charges [Member]
Loss on reacquired debt [Member]
Loss on Reacquired Debt [Member]
Cost of removal, asset [Member]
Cost of Removal Asset [Member]
Discloses the amount of regulatory asset arising from costs of disposing of long lived assets, whether by demolishing, dismantling, abandoning, sale, and so forth during the period.
Asset Retirement Obligation Costs [Member]
Pension and post-retirement costs [Member]
Pension Costs [Member]
Deferred customer programs [Member]
Deferred Customer Programs [Member]
Discloses the amount of regulatory asset arising from deferred customer program.
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.
Fuel recovery mechanisms [Member]
Deferred Fuel Costs [Member]
Acquisition transition costs [Member]
Acquisition Transition Costs [Member]
Discloses the amount of regulatory asset arising from acquisition transition costs not included in rate base.
Derivative instruments [Member]
Derivative Instruments [Member]
Discloses the fair value of derivative instruments for commodity contracts.
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.
Solar Rebates [Member]
Solar Rebates [Member]
Regulatory asset arising from costs related to solar rebates.
Voluntary Separation Program [Member]
Voluntary Separation Program [Member]
Regulatory asset arising from costs related to the voluntary separation program.
Other regulatory noncurrent assets [Member]
Other Regulatory Non Current Assets [Member]
Discloses the amount of regulatory asset arising from other insignificant items that are both included in rate base and not included in rate base and amortized over various periods.
Regulatory Assets [Line Items]
Regulatory Assets [Line Items]
Regulatory Assets, Noncurrent
Amount not included in rate base
Amount Not Included In Rate Base
Amount included in regulatory assets but not included in rate base and amortized through various periods.
Regulatory amortization period
Regulatory Noncurrent Asset, Amortization Period
Regulatory Liability, Noncurrent
Equity Compensation
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]
Schedule of Segment Reporting Information, by Segment [Table]
Business Segments [Axis]
Segment [Domain]
Electric Utility Segment [Member]
Reportable Segment [Member]
All Other Segments [Member]
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization
Discontinued operations
Assets, Total
Capital expenditures
Segment Reporting Information, Expenditures for Additions to Long-Lived Assets
Schedule of Stock by Class [Table]
Schedule of Stock by Class [Table]
No Par Preference Stock [Member]
No Par Preference Stock [Member]
Preference stock, with no stated par value, authorized under the Articles of Incorporation.
Cumulative No Par Preferred Stock [Member]
Cumulative No Par Preferred Stock [Member]
Preferred stock, with no stated par value, upon which unpaid dividends accumulate until paid to shareholders. Classified within stockholders' equity if nonredeemable of redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer.
Class of Stock [Line Items]
Class of Stock [Line Items]
Preferred Stock, Shares Authorized
Preferred Stock, Shares Authorized
Preferred Stock, Shares Outstanding
Preferred Stock, Shares Outstanding
Preferred Stock, Value, Outstanding
Preferred Stock, Value, Outstanding
Optional Redemption Percentage of Par Value
Optional Redemption Percentage of Par Value
The percentage of par value at which the preferred stock may be redeemed at the option of the Company.
Amortization of:
Amortization [Abstract]
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.
Other Amortization of Deferred Charges
Investment tax credit amortization
Investment Tax Credit
Loss from equity investments, net of income taxes
Other operating activities
Utility capital expenditures
Payments to Acquire Property, Plant, and Equipment
Allowance for borrowed funds used during construction
Allowance For Borrowed Funds Used During Construction
Cash outflow due to change during the period in the allowance for other funds used during construction classified as an investing activity.
Payment to Black Hills for asset sale working capital adjustment
Payments for (Proceeds from) Businesses and Interest in Affiliates
Purchases of nuclear decommissioning trust investments
Payments to Acquire Investments to be Held in Decommissioning Trust Fund
Proceeds from nuclear decommissioning trust investments
Proceeds from Decommissioning Trust Fund Assets
Net money pool lending
Other investing activities
Payments for (Proceeds from) Other Investing Activities
Repayment of long-term debt
Repayments of Long-term Debt
Net change in collateralized short-term borrowings
Proceeds from (Repayments of) Other Debt
Net money pool borrowings
Net money pool borrowings
Net proceeds (payments) in money pool borrowings.
Cash Flow, Supplemental Disclosures [Text Block]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
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]
Summary of Income Tax Contingencies [Table Text Block]
Nuclear fuel, amortization
Nuclear Fuel Accumulated Amortization
Amortization based on the energy produced over the life of the fuel.
Capitalization
Common shareholder's equity
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Common stock - shares authorized (in shares)
Common stock-shares issued (in shares)
Treasury stock- shares (in shares)
Cumulative preferred stock
Cumulative preferred stock par value (in dollars per share)
Cumulative preferred stock, Shares issued (in share)
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
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
Schedule of Defined Benefit Plans Disclosures [Table]
Defined Benefit Plans and Other Postretirement Benefit Plans [Axis]
Defined Benefit Plans and Other Postretirement Benefit Plans [Domain]
Defined Benefit Plan Disclosure [Line Items]
Fair value of assets using significant unobservable inputs
Schedule of Net Funded Status [Table Text Block]
Schedule of Net Benefit Costs [Table Text Block]
Schedule of Net Benefit Costs [Table Text Block]
Periodic benefit obligation and accumulated benefit obligation and the fair value of plan assets by funded and under funded plans
Schedule of periodic benefit obligation and accumulated benefit obligation and the fair value of plan assets by funded and under funded plans [Table Text Block]
Tabular disclosure of periodic benefit obligation and accumulated benefit obligation and the fair value of plan assets by funded and under funded plans.
Schedule of Assumptions Used [Table Text Block]
Schedule of Expected Benefit Payments [Table Text Block]
Fair Value of Plan Assets [Table Text Block]
Schedule of Allocation of Plan Assets [Table Text Block]
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block]
Public Utility, Property, Plant and Equipment [Table]
Public Utility, Property, Plant and Equipment [Table]
Public Utility [Axis]
Public Utility [Axis]
Utility Plant [Domain]
Utility Plant [Domain]
Land and other assets not depreciated [Member]
Land and other assets not depreciated [Member]
Land and other assets not depreciated [Member]
Energy Plan [Member]
Energy Plan [Member]
Additional amortization allowed to help maintain cash flows during KCPL's Comprehensive Energy Plan pursuant to orders of the Public Service Commission of the State of Missouri (MPSC) and the State Corporation Commission of the State of Kansas (KCC).
Regulation Status [Axis]
Regulation Status [Axis]
Regulated and Unregulated Operation [Domain]
Regulated and Unregulated Operation [Domain]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utility, Property, Plant and Equipment [Line Items]
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
Depreciation
Depreciation
Public Utilities, Property, Plant and Equipment, Generation, Estimated Useful Life
Public Utilities, Property, Plant and Equipment, Generation, Estimated Useful Life
Public Utilities, Property, Plant and Equipment, Transmission, Estimated Useful Life
Public Utilities, Property, Plant and Equipment, Transmission, Estimated Useful Life
Public Utilities, Property, Plant and Equipment, Distribution, Estimated Useful Life
Public Utilities, Property, Plant and Equipment, Distribution, Estimated Useful Life
Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Estimated Useful Life
Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Estimated Useful Life
Public Utilities, Allowance for Funds Used During Construction, Rate
Public Utilities, Allowance for Funds Used During Construction, Rate
Utility Plant, at original cost
Public Utilities, Property, Plant and Equipment, Plant in Service [Abstract]
Public Utilities, Property, Plant and Equipment, Generation or Processing
Public Utilities, Property, Plant and Equipment, Generation or Processing
Public Utilities, Property, Plant and Equipment, Transmission
Public Utilities, Property, Plant and Equipment, Transmission
Public Utilities, Property, Plant and Equipment, Distribution
Public Utilities, Property, Plant and Equipment, Distribution
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment
Public Utilities, Property, Plant and Equipment, Plant in Service
Quarterly Financial Information [Text Block]
Schedule of Short-term Debt [Table]
Short-term Debt [Line Items]
Amount of revolving credit facility
Line of Credit Facility, Maximum Borrowing Capacity
Revolving credit facility expiration date
Line of Credit Facility, Expiration Date
Covenant term - amount considered in default
Covenant Term Debt Default Short Term Debt Amount
Amount of other indebtedness considered a default under the revolving credit facility.
Covenant Term Ratio of Consolidated Indebtedness to Consolidated Capitalization Ratio, Maximum
Covenant Term Ratio Of Consolidated Indebtedness To Consolidated Capitalization Ratio Maximum
The maximum ratio of consolidated indebtedness to consolidated capitalization ratio, as defined in the agreement that the company is required to comply with at all times.
Line of Credit Facility, Covenant Compliance
Line of Credit Facility, Covenant Compliance
Weighted-average interest rate from outstanding borrowings
Short-term Debt, Weighted Average Interest Rate
Amount of letters of credit outstanding
Excise and Sales Taxes
Excise and Sales Taxes
Receivables [Abstract]
Contractually Specified Servicing Fees Percentage Amount
Percentage amounts that, per contract, are due to the servicer in exchange for servicing the financial asset and would no longer be received by a servicer if the beneficial owners of the serviced assets (or their trustees or agents) were to exercise their actual or potential authority under the contract to shift the servicing to another servicer.
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 June 1 to October 31 of each year
Maximum amount of outstanding principal under receivables agreement from June 1 to October 31 of each year
Maximum amount of outstanding principal under receivables agreement from June 1 to October 31 of each year.
Maximum amount of outstanding principal under receivables agreement from November 1 to May 31 of each year
Maximum amount of outstanding principal under receivables agreement from November 1 to May 31 of each year
Maximum amount of outstanding principal under receivables agreement from November 1 to May 31 of each year
Fair Value Measurements, Recurring and Nonrecurring [Table]
Measurement Frequency [Axis]
Fair Value, Measurement Frequency [Domain]
Fair Value, Measurements, Recurring [Member]
Fair Value, Hierarchy [Axis]
Fair Value, Measurements, Fair Value Hierarchy [Domain]
Netting [Member]
Fair Value, Inputs, Level 1 [Member]
Fair Value, Inputs, Level 2 [Member]
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash collateral posted with third parties as part of netting agreements
Collateral Already Posted, Aggregate Fair Value
Cash and cash equivalents from SERP rabbi trust excluded from fair value disclosure
Fair Value Assets Measured On Recurring Basis Cash And Cash Equivalents From Serp Rabbi Trust
This element represents the cash and cash equivalents that are part of the SERP rabbi trust that are not subject to the fair value requirements.
Cash and cash equivalents from nuclear decommissioning trust excluded from fair value disclosure
Fair Value Assets Measured On Recurring Basis Cash And Cash Equivalents From Nuclear Decommissioning Trust
This element represents the cash and cash equivalents that are part of the nuclear decommissioning trust that are not subject to the fair value requirements.
Assets [Abstract]
Assets, Fair Value Disclosure [Abstract]
Derivative instruments, assets
Derivative Assets
Nuclear decommissioning trust [Abstract]
Equity securities related to nuclear decommissioning trust
Fair Value Assets Measured On Recurring Basis Equity Securities Related To Nuclear Decommissioning Trust
Fair value disclosure of equity securities included in the decommissioning trust assets.
Debt securities related to nuclear decommissioning trust [Abstract]
Debt securities related to nuclear decommissioning trust [Abstract]
U.S. Treasury
Fair Value Assets Measured On Recurring Basis Us Treasury Debt Securities Related To Nuclear Decommissioning Trust
This element represents the fair value disclosure of assets measured on a recurring basis that are related to U.S. treasury debt securites that are part of the nuclear decommissioning trust.
U.S. Agency
Fair Value Assets Measured On Recurring Basis Us Agency Debt Securities Related To Nuclear Decommissioning Trust
This element represents the fair value disclosure of assets measured on a recurring basis that are related to U.S. agency debt securites that are part of the nuclear decommissioning trust.
State and local obligations
Fair Value Assets Measured On Recurring Basis State And Local Obligations Debt Securities Related To Nuclear Decommissioning Trust
This element represents the fair value disclosure of assets measured on a recurring basis that are related to state and local obligations debt securites that are part of the nuclear decommissioning trust.
Corporate bonds
Fair Value Assets Measured On Recurring Basis Corporate Bonds Debt Securities Related To Nuclear Decommissioning Trust
This element represents the fair value disclosure of assets measured on a recurring basis that are related to corporate bonds debt securites that are part of the nuclear decommissioning trust.
Foreign governments
Fair Value Assets Measured On Recurring Basis Foreign Governments Debt Securities Related To Nuclear Decommissioning Trust
This element represents the fair value disclosure of assets measured on a recurring basis that are related to foreign governments debt securites that are part of the nuclear decommissioning trust.
Other assets related to nuclear decommissioning trust
Fair Value Assets Measured On Recurring Basis Other Assets Related To Nuclear Decommissioning Trust
This element represents the fair value disclosure of assets measured on a recurring basis that are related to other assets that are part of the nuclear decommissioning trust.
Total nuclear decommissioning trust
Fair Value Assets Measured On Recurring Basis Total Related To Nuclear Decommissioning Trust
This element represents the fair value disclosure of assets measured on a recurring basis that are related to the nuclear decommissioning trust.
SERP rabbi trust [Abstract]
Equity securities related to SERP rabbi trust
Fair Value Assets Measured On Recurring Basis Equity Securities Related To Serp Rabbi Trust
This element represents the fair value disclosure of assets measured on a recurring basis that are related to equity securites that are part of the SERP rabbi trust.
Debt securities related to SERP rabbi trust
Fair Value Assets Measured On Recurring Basis Debt Securities Related To Serp Rabbi Trust
This element represents the fair value disclosure of assets measured on a recurring basis that are related to debt securites that are part of the SERP rabbi trust.
Total SERP rabbi trust
Fair Value Assets Measured On Recurring Basis Total Related To Serp Rabbi Trust
Total assets measured at fair value on a recurring basis included in the SERP rabbi trust.
Total assets
Fair Value Assets Measured On Recurring Basis Total
The total fair value of assets measured on recurring basis.
Liabilities [Abstract]
Liabilities, Fair Value Disclosure [Abstract]
Derivative instruments, liabilities
Derivative Financial Instruments, Liabilities, Fair Value Disclosure
Total liabilities
Fair Value Liabilities Measured On Recurring Basis Total
The total fair value of liabilities measured on recurring basis.
Regulatory assets
Schedule of Regulatory Assets [Table Text Block]
Regulatory liabilities
Schedule of Regulatory Liabilities [Table Text Block]
Schedule of Jointly Owned Utility Plants [Table Text Block]
Guarantees [Text Block]
Equity [Abstract]
Common Shareholders' Equity [Abstract]
Shares authorized under the Dividend Reinvestment and Direct Stock Purchase Plan (in shares)
Dividend reinvestment and direct stock purchase plan number of shares registered
The number of shares registered with the Securities and Exchange Commission for the Dividend Reinvestment and Direct Stock Purchase Plan.
Number of shares available for grant under the Dividend Reinvestment and Direct Stock Purchase Plan (in shares)
Dividend reinvestment and direct stock purchase plan number of shares available for issuance
The difference between the maximum number of shares registered for issuance under the Dividend Reinvestment and Direct Stock Purchase Plan (including the effects of amendments and adjustments), and the number of shares already issued.
Shares registered under the defined contribution savings plan (in shares)
Defined contribution savings plan number of shares registered
The number of shares registered with the Securities and Exchange Commission for the defined contribution savings plan.
Number of shares available under the defined contribution savings plan (in shares)
Defined contribution plan number of shares available
The difference between the maximum number of shares authorized for issuance under the defined contribution plan (including the effects of amendments and adjustments), and the number of shares already issued.
Restrictions on the payment of common stock dividends contained in the articles of incorporation
Other Restrictions on Payment of Dividends
Regulatory restrictions on the payment of dividends
MPSC and KCC restrictions on payment of dividends
Statement regarding MPSC and KCC regulations related to restrictions on GPE and KCPL's ability to pay dividends.
Consolidated indebtedness to consolidated total capitalization ratio required under the revolving credit agreement
Debt Instrument, Covenant Description
Restricted net assets of subsidiaries
Amount of Restricted Net Assets for Consolidated and Unconsolidated Subsidiaries
Selling, general and administrative
General taxes
Operating Expenses
Operating Expenses
Equity in earnings (loss) from Subsidiaries
Weighted Average Number of Shares Outstanding, Basic
Weighted Average Number of Shares Outstanding, Diluted
Income tax benefit (expense) on derivative hedging instruments
Reclassification to expenses
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax
Income tax (benefit) expense on reclassification to expenses
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Tax
Reclassification to expenses, net of tax
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 (loss)
Jointly Owned Utility Plant Interests [Table]
Jointly Owned Utility Plant Interests [Table]
Jointly Owned Utility Plant [Axis]
Jointly Owned Utility Plant [Axis]
Jointly Owned Utility Plant [Domain]
Jointly Owned Utility Plant [Domain]
Jointly Owned Electricity Generation Plant [Member]
Jointly Owned Electricity Generation Plant [Member]
Jointly Owned Nuclear Power Plant [Member]
Jointly Owned Nuclear Power Plant [Member]
Wolf Creek Unit [Member]
Wolf Creek Unit [Member]
Information on the Wolf Creek jointly owned nuclear utility plant.
LaCygne Station [Member]
Iatan No. 1 [Member]
Iatan No 1 [Member]
Information on the jointly owned Iatan No. 1 electric utility plant.
Iatan No. 2 [Member]
Iatan No. 2 [Member]
Information on the jointly owned Iatan No. 2 electric utility plant.
Iatan Common [Member]
Iatan Common [Member]
Information on the jointly owned Iatan Common electric utility plant.
Jeffrey Energy Center [Member]
Jeffrey Energy Center [Member]
Information on the jointly owned Jeffrey Energy Center electric utility plant.
Jointly Owned Utility Plant Interests [Line Items]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share (in hundredths)
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
Construction work in progress
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress
Accredited capacity (in MW's)
Accredited Capacity
The accredited capacity of the jointly owned electric utility plant, in megawatts.
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]
Award Type [Axis]
Award Type [Axis]
Award Type [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares of common shares authorized (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized
Compensation expense
Allocated Share-based Compensation Expense
Income tax benefits
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 range (in hundredths)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Range of Dividends Used
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]
Beginning balance (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number
Granted (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period
Earned (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Earned in Period
The number of equity-based payment instruments, excluding stock (or unit) options, that were earned during the reporting period.
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
Performance adjustment (in shares)
Share-based Compensation Arrangement by Share-based payment Award, Equity Instruments Other than Options, Performance adjustment
The number of equity-based payment instruments, excluding stock (or unit) options, that were adjusted during the reporting period based on performance criteria.
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 earned (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Earned in period, weighted average grant date fair value
The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee earned the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.
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 performance adjustment (in dollars per share)
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Performance Adjustments Weighted Average Grant Date Fair Value
Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were adjusted during the reporting period based on performance criteria.
Weighted average ending balance (in dollars per share)
Total unrecognized compensation expense
Employee Service Share-based Compensation, Nonvested Awards, Total 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, Total 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
Fair value of performance shares earned and paid
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Earned And Paid Total Fair Value
The total fair value of equity-based awards for which the grantee earned and was paid during the reporting period by satisfying service and performance requirements.
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 Type [Domain]
Receivable Type [Domain]
Trade Accounts Receivable [Member]
Trade Accounts Receivable [Member]
Intercompany Receivables [Member]
Intercompany Receivables [Member]
Intercompany receivables.
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]
Accounts Receivable, Gross, Current
Accounts Receivable, Gross, Current
Allowance for doubtful accounts
Allowance for Doubtful Accounts Receivable, Current
Other Receivables, Gross, Current
Other Receivables, Gross, Current
Organization [Policy Text Block]
Consolidation, Policy [Policy Text Block]
Use of Estimates [Policy Text Block]
Use of Estimates, Policy [Policy Text Block]
Cash and Cash Equivalents [Policy Text Block]
Cash and Cash Equivalents, Policy [Policy Text Block]
Funds on Deposit [Policy Text Block]
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]
Fair Value of Financial Instruments [Policy Text Block]
Fair Value of Financial Instruments, Policy [Policy Text Block]
Derivative Instruments [Policy Text Block]
Derivatives, Policy [Policy Text Block]
Utility Plant [Policy Text Block]
Property, Plant and Equipment, Policy [Policy Text Block]
Depreciation and Amortization [Policy Text Block]
Regulatory Depreciation and Amortization, Policy [Policy Text Block]
Nuclear Plant Decommissioning Costs [Policy Text Block]
Asset Retirement Obligations, Policy [Policy Text Block]
Deferred Refueling Outage Costs [Policy Text Block]
Property, Plant and Equipment, Planned Major Maintenance Activities, Policy [Policy Text Block]
Regulatory Matters [Policy Text Block]
Public Utilities, Policy [Policy Text Block]
Revenue Recognition [Policy Text Block]
Revenue Recognition, Policy [Policy Text Block]
Allowance for Doubtful Accounts [Policy Text Block]
Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy
Property Gains and Losses [Policy Text Block]
Property Gains and Losses [Policy Text Block]
Disclosure of accounting policy for gains and losses on sales of property and from asset impairments.
Asset Impairments [Policy Text Block]
Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block]
Income Taxes [Policy Text Block]
Income Tax, Policy [Policy Text Block]
Environmental Matters [Policy Text Block]
Regulatory Environmental Costs, Policy [Policy Text Block]
Basic and Diluted Earnings per Common Share Calculation [Policy Text Block]
Earnings Per Share, Policy [Policy Text Block]
Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Table]
Derivative Instrument Risk [Axis]
Derivative Contract Type [Domain]
Interest Rate Contract [Member]
Commodity Contract [Member]
Income tax benefit (expense) [Member]
Income tax benefit (expense) [Member]
Benefit (expense) from income taxes due to gain (loss) recognized.
Regulatory Account [Member]
Regulatory Account [Member]
Derivative instruments in a regulatory account relationship.
Income Statement Location [Axis]
Income Statement Location [Domain]
Interest charges [Member]
Interest Expense [Member]
Fuel Costs [Member]
Fuel costs incurred that are directly related to goods produced and sold and services rendered during the reporting period.
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net
Gain(Loss) Reclassified from Regulatory Account into Income (Effective Portion)
Derivative Instruments Gain Loss Reclassified From Regulatory Account Into Income On Derivatives
The income statement location of the effective portion of net gain or loss reclassified from regulatory account into income on derivative instruments designated and qualifying as hedging instruments.
Amount of Gain (Loss) Recognized on Regulatory Account on Derivatives (Effective Portion)
Derivative Instruments Gain Loss Recognized In Regulatory Account On Derivatives
The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in regulatory account during the current period.
Receivables [Text Block]
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.
Preferred Stock [Member]
Accounts receivable from subsidiaries
Due from Related Parties, Current
Notes receivable from subsidiaries, current
Notes receivable from subsidiaries
Aggregate value of notes receivable from subsidiaries, current.
Money pool receivable
Money pool receivable
Amount receivable under the Great Plains Energy money pool, an internal financing arrangement.
Taxes receivable
Other current assets
Other Assets, Current
Investment in KCP&L
Investment in KCPL
This item represents the carrying amount of Great Plains Energy's investment in KCPL, its other reporting consolidated subsidiary, presented as an equity method investment for stand-alone presentation of the parent company.
Investment in other subsidiaries
Investment in other subsidiaries
This item represents the carrying amount of Great Plains Energy's investments in other subsidiaries (other than KCPL) presented as equity method investments for stand-alond reporting of the parent company.
Notes receivable from subsidiaries, noncurrent
Note receivable from subsidiaries
Aggregate value of notes receivable from subsidiaries, noncurrent
Deferred income taxes
Other investments and other assets
Total investments and other assets
Assets, Noncurrent
Accounts payable to subsidiaries
Due to Related Parties, Current
Other current liabilities
Liabilities, Noncurrent, Total
Capitalization
Capitalization, Long-term Debt and Equity [Abstract]
Accumulated Other Comprehensive Income (Loss), Net of Tax
Total Capitalization
Commitments and Contingencies
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)
Foreign
Current Foreign Tax Expense (Benefit)
Current Income 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)
Deferred Income Tax Expense (Benefit), Total
Noncurrent income taxes
Noncurrent Income Tax Expense Benefit Continuing Operations [Abstract]
Federal
Noncurrent Federal Tax Expense Benefit
The noncurrent component of income tax expense for the period representing amounts paid or payable (or refundable) as determined by applying the provisions of enacted federal tax law to the domestic taxable Income or Loss from continuing operations.
State
Noncurrent State And Local Tax Expense Benefit
The noncurrent component of income tax expense for the period representing amounts paid or payable (or refundable) as determined by applying the provisions of enacted state and local tax law to relevant amounts of taxable Income or Loss from continuing operations.
Foreign
Noncurrent Foreign Tax Expense Benefit
The noncurrent component of income tax expense for the period representing amounts paid or payable (or refundable) as determined by applying the provisions of foreign enacted tax law to the foreign taxable Income or Loss from continuing operations.
Noncurrent Income Tax Expense (Benefit), Total
Noncurrent Income Tax Expense Benefit
The noncurrent component of income tax expense for the period representing amounts of income taxes paid or payable (or refundable) for the period for all income tax obligations as determined by applying the provisions of relevant enacted tax laws to relevant amounts of taxable Income or Loss from continuing operations.
Investment tax credit
Investment tax credit [Abstract]
Deferral
Investment Tax Credit, Deferral
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 deferral of investment tax credits.
Amortization
Investment Tax Credit, Total
Investment Tax Credit, Total
Total investment tax credit included in current tax expense.
Total income tax expense
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Federal statutory income tax (in hundredths)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate
Differences between book and tax depreciation not normalized (in hundredths)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Depreciation
Amortization of investments tax credits (in hundredths)
Effective Income Tax Rate Reconciliation, Tax Credits, Investment
Federal income tax credits (in hundredths)
Effective Income Tax Rate Reconciliation, Tax Credits, Other
State income taxes (in hundredths)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate
Effective Income Tax Rate Reconciliation, Deductions, Medicare Prescription Drug Benefit
Changes in uncertain tax positions, net (in hundredths)
Effective Income Tax Rate Reconciliation, Tax Contingencies
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance
Effective Income Tax Rate Reconciliation, Other Adjustments
Effective Income Tax Rate Reconciliation, Other Adjustments
Effective Income Tax Rate, Continuing Operations, Total
Effective Income Tax Rate, Continuing Operations
Pension Plans Fair Value Disclosure [Abstract]
Pension Plans Fair Value Disclosure [Abstract]
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Asset Categories [Axis]
Defined Benefit Plan, Asset Categories [Axis]
Plan Asset Categories [Domain]
Real Estate [Member]
Hedge Funds [Member]
Limited Partnerships Equity Securities [Member]
This category includes information about ownership interests or the right to acquire ownership interests in limited partnerships which ownership interest is represented by common or preferred units (which is neither mandatorily redeemable no redeemable at the option of the holder), convertible securities, unit rights, or unit warrants.
Equity Securities [Member]
US Equity Securities [Member]
This category includes information about ownership interests or the right to acquire ownership interests in United States' corporations and other legal entities which ownership interest is represented by shares of common or preferred stock (which is neither mandatorily redeemable no redeemable at the option of the holder), convertible securities, stock rights, or stock warrants.
International Equity Securities [Member]
This category includes information about ownership interests or the right to acquire ownership interests in foreign corporations and other legal entities which ownership interest is represented by shares of common or preferred stock (which is neither mandatorily redeemable no redeemable at the option of the holder), convertible securities, stock rights, or stock warrants.
Fixed Income Funds [Member]
US Treasury [Member]
US Treasury Securities [Member]
US Agency, State and Political Subdivisions Debt Securities [Member]
This category includes information about bonds or similar securities issued by state, city, or local governments or the agencies operated by federal, state, city, or local governments.
US corporate bonds [Member]
Domestic Corporate Debt Securities [Member]
Foreign corporate bonds [Member]
Foreign Corporate Debt Securities [Member]
Cash and Cash Equivalents [Member]
US States and Political Subdivisions Debt Securities [Member]
Total
Total Plan Assets [Member]
Total of all Level 1, Level 2, and Level 3 assets excluding cash and cash equivalents.
Defined benefit plan, Type of mutual fund and corporate bonds, by type [Axis]
The type of mutual funds and corporate bonds making up the various types of plan assets for valuation purposes.
Defined Benefit Plan, Mutual Fund and Corporate Bonds Type [Domain]
The type of mutual funds and corporate bonds used for plan asset evaluation.
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]
This category is used for institutional common/collective trust funds valued at daily Net Asset Values per share.
Corporate Bonds [Member]
Individual corporate bonds held as part of plan assets.
Collateralized Mortgage Obligation Securities [Member]
Plan assets consisting of collateralized mortgage obligations.
Asset-backed Securities [Member]
Fair Value, Plan Assets
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]
Relating to assets still held
Defined Benefit Plan, Actual Return on Plan Assets Still Held
Relating to assets sold
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period
Purchase, sales and settlements
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, Sales, Issues, Settlements
Legal Proceedings [Text Block]
Schedule of Loss Contingencies by Contingency [Table Text Block]
Schedule of Regulatory Liabilities [Table]
Schedule of Regulatory Liabilities [Table]
Regulatory Liability [Axis]
Regulatory Liability [Axis]
Regulatory Liability [Domain]
Regulatory Liability [Domain]
Emission allowances [Member]
Emission Allowances [Member]
Discloses the amount of regulatory liability arising from emission allowances sales.
Asset retirement obligations [Member]
Pension [Member]
Pension Cost [Member]
Cost of removal, liability [Member]
Cost Of Removal [Member]
Estimated cumulative net provision for future removal costs.
Other regulatory noncurrent liabilities [Member]
Other Regulatory Non Current Liabilities [Member]
Discloses the amount of regulatory liability arising from other insignificant items.
Regulatory Liabilities [Line Items]
Regulatory Liabilities [Line Items]
Segments and Related Information
Segment Reporting Disclosure [Text Block]
Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]
Designated as Hedging Instrument [Member]
Balance Sheet Location [Axis]
Balance Sheet Location [Domain]
Derivative [Member]
Current assets [Member]
Amounts recorded in current assets for open derivative positions or at the time of settlement of a closed position.
Current liabilities [Member]
Amounts recorded in current liabilities for open derivative positions or at the time of settlement of a closed position.
Noncurrent liabilities [Member]
Amounts recorded in noncurrent liabilities for open derivatvie positions or at the time of settlement of a closed position.
Deferred income taxes [Member]
Amounts recorded in deferred income taxes for open derivative positions or at the time of settlement of a closed position.
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, amount not offset against collateral
Derivative Asset, Fair Value, Amount Not Offset Against Collateral
Derivative liability, fair value, amount not offset against collateral
Derivative Liability, Fair Value, Amount Not Offset Against Collateral
Recorded amounts included in accumulated other comprehensive income
Derivatives Included In Accumulated Other Comprehensive Income Recorded Value
The value recorded in accumulated other comprehensive income.
Schedule of receivables [Table Text Block]
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]
Schedule of accounts receivable sold [Table Text Block]
Accounts Receivables Sold Disclosure [Table Text Block]
Disclosure itemizing the receivables purchased (sold) and the gain (loss) on the sale. It also discloses the cash flows recognized on the sales of receivables.
Schedule Of Accounts Receivable Sold [Table]
Kansas City Power And Light Company Unconsolidated [Member]
Kansas City Power And Light Company Unconsolidated [Member]
Information related to Kansas City Power and Light Company, unconsolidated.
KCPL Receivables Company [Member]
Kcpl Receivables Company Member
Information related to KCPL Receivables Company, a wholly owned subsidiary of Kansas City Power and Light Company.
GMO Receivables Company Member
GMO Receivables Company Member
Information related to GMO Receivables Company, a wholly owned subsidiary of KCPL Greater Missouri Operations.
Accounts Receivable Sold [Line Items]
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
Receivables (sold) purchased
Receivables (Sold) Purchased
Receivables (sold) to wholly owned subsidiary receivables ompany or purchased by parent company.
Gain (Loss) on Sale of Accounts Receivable
Gain (Loss) on Sale of Accounts Receivable
Servicing fees received (paid)
Ancillary Fee Income Generated by Servicing Financial Assets, Amount
Fees paid to outside investor
Ancillary Fee to Outside Investor
All amounts that are due or paid to outside investor related specifically to accounts receivable sold.
Cash from customers (transferred to) received from Receivables Company
Proceeds From Customers In Accounts Receivable Transferred
Cash received from customers or (transferred) to receivables company.
Cash received from (paid to) for receivables purchased
Cash Received From (Paid To) Transferring Entity for receivables purchased
Cash received from (paid to) transferring entity for sale of accounts receivable
Interest on intercompany note received (paid)
Intercompany Interest Income (Expense) On Notes
Amount received (paid) for interest on intercompany notes
Schedule II Valuation and Qualifying Accounts
Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]
Regulatory Matters
Public Utilities Disclosure [Text Block]
Schedule of Related Party Transactions, by Related Party [Table]
Related Party [Axis]
Related Party [Domain]
Great Plains Energy [Member]
Information on Great Plains Energy.
Related Party Transaction [Line Items]
Receivable from Related Party
KCP and L employees manage GMO's business and operate its facilities at cost
Related Party Transaction, Amounts of Transaction
KCP and L net wholesale sales to GMO
Related Party Transaction, Other Revenues from Transactions with Related Party
Schedule of Debt [Table Text Block]
Amortization of debt expense [Table Text Block]
Amortization of debt expense [Table Text Block]
Tabular disclosure of the component of interest expense representing the noncash expenses charged against earnings in the period to amortize debt discount and premium associated with the related debt instruments. Alternate caption: Noncash Interest Expense.
Schedule of Maturities of Long-term Debt [Table Text Block]
Nuclear Plant [Table]
Nuclear Plant [Table]
Disclosures regarding the nuclear plant including decommissioning costs and nuclear insurance
Jointly Owned Utility Plant, by Plant [Axis]
Jointly owned utility plant, by the plant.
Nuclear Plant Decommissioning Costs [Abstract]
Nuclear Plant Decommissioning Costs [Abstract]
Nuclear Plant Decommissioning Costs [Abstract]
Current cost of decommissioning (in 2011 dollars)
Current cost of decommissioning (in 2011 dollars)
This represents the current cost of decommissioning the Wolf Creek generating station.
Future cost of decommissioning (in 2045 through 2053 dollars)
Future cost of decommissioning (in 2045-2053 dollars)
This represents the cost of decommissioning the Wolf Creek generating station in expected dollars at the time of decommissioning.
Annual Escalation Factor
Annual Escalation Factor
Annual escalation factor applied to decommissioning costs in current year dollars to arrive at future costs of decommissioning.
Annual return on trust assets through 2025
Annual return on trust assets through 2025
This represents the expected rate of return on assets held in the nuclear decommissioning trust through 2025.
Annual return on trusts assets beginning in 2053
Annual return on trusts assets beginning in 2053
The expected rate of return on assets held in the nuclear decommissioning trust is expected to decline to this amount after 2025 through 2053 as the fund's investment mix will increasingly become more conservative as the decommissioning period approaches.
Nuclear Insurance [Abstract]
Nuclear Insurance [Abstract]
Nuclear Insurance [Abstract]
Industry aggregate limit on nuclear insurance for property claims including accidental damages
Industry aggregate limit on nuclear insurance for property claims including accidental damages
Industry aggregate limit on nuclear insurance for property claims including accidental outage.
Amount of insurance against public liability claims resulting from nuclear incidents to full limit of public liability
Amount of insurance against public liability claims resulting from nuclear incidents to full limit of public liability
Amount of insurance against public liability claims resulting from nuclear incidents to the full limit of public liability.
Maximum available commercial insurance
Maximum available commercial insurance
Maximum available commercial insurance.
Remaining balance provided through industry wide retrospective assesment program mandated by law
Remaining balance provided through industry wide retrospective assesment program mandated by law
Remaining balance of public liability limits provided through industry wide retrospective assesment program mandated by law.
Maximum amount able to be assessed to owners
Maximum amount able to be assessed to owners
Maximum amount able to be assessed to owners.
SFP Program-annual amount payable per incident
SFP Program-annual amount payable per incident
Under the Secondary Financial Protection (SPF) program, amount that owners can be assessed per nuclear incident per year.
Amount of decontamination liability, premature decommissioning liability and property damage insurance
Amount of decontamination liability, premature decommissioning liability and property damage insurance
Amount of decontamination liability, premature decommissioning liability and property damage insurance.
Premature decommissioning coverage applies only if property damage exceeds this amount and trust funds have been exhausted
Premature decommissioning coverage applies only if property damage exceeds this amount and trust funds have been exhausted
Premature decommissioning coverage applies only if property damage exceeds this amount and trust funds have been exhausted.
Estimated maximum amount of retrospective assessments under the current policies
Estimated maximum amount of retrospective assessments under the current policies
Estimated maximum amount of retrospective assessments under the current policies.
Ownership percentage in Wolf Creek, a nuclear generating unit (in hundredths)
Equity Method Investment, Ownership Percentage
Nuclear decommissioning trust [Abstract]
Nuclear decommissioning trust fund [Roll Forward]
Nuclear decommissioning trust fund [Roll Forward]
Nuclear decommissioning trust fund [Roll Forward]
Nuclear decommissioning trust fund, beginning balance
Contributions to nuclear decommissioning trust fund
Contributions To Decommissioning Trust Fund
This represents total contributions to the decommissioning trust fund during the current period.
Nuclear decommissioning trust fund earned income, net of fees
Decommissioning Trust Fund Earned Income Net Of Fees
This represents income earned, net of fees, on decommissioning trust fund investments during the current period.
Net realized gains (losses) on nuclear decommissioning trust fund
Net Realized Gains Losses On Decommissioning Trust Fund
This represents the net realized gains (losses) on decommissioning trust fund investments during the current period.
Net unrealized gains (losses) on nuclear decommissioning trust fund
Net Unrealized Gains Losses On Decommissioning Trust Fund
This represents the net unrealized gains (losses) on decommissioning trust fund investments during the current period.
Nuclear decommissioning trust fund, ending balance
Fair Value, by Balance Sheet Grouping [Table]
Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis]
Fair Value, Disclosure Item Amounts [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt fair value
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.