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PENSION PLANS AND POST-RETIREMENT BENEFITS - Narrative (Details) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 USD ($) Rate | Dec. 31, 2019 USD ($) | Dec. 31, 2020 | Dec. 31, 2020 USD ($)
Pension Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Settlement and special termination benefits | $ 11.2 | $ 15.6 |  |
Non-qualified benefit obligations |  | 49.4 |  | $ 52.1
Funded by trusts containing assets |  | $ 45.5 |  | 46.3
Contributions to plans in next year |  |  |  | 131.6
Defined benefit plan basis point change in discount rate | 70 | 70 |  |
Post-Retirement Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Settlement and special termination benefits | $ 0.0 | $ 0.0 |  |
Contributions to plans in next year |  |  |  | 4.1
Evergy Kansas Central | Pension Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Settlement and special termination benefits | $ 0.0 | 0.0 |  |
Non-qualified benefit obligations |  | 26.0 |  | 27.0
Funded by trusts containing assets |  | $ 31.7 |  | 32.7
Contributions to plans in next year |  |  |  | 41.2
Defined benefit plan basis point change in discount rate | 70 | 70 |  |
Evergy Kansas Central | Post-Retirement Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Settlement and special termination benefits | $ 0.0 | $ 0.0 |  |
Contributions to plans in next year |  |  |  | 0.6
Evergy Metro | Pension Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Settlement and special termination benefits | $ 14.3 | $ 23.0 |  |
Contributions to plans in next year |  |  |  | 90.4
Defined benefit plan basis point change in discount rate | 70 | 70 |  |
Evergy Metro | Post-Retirement Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Settlement and special termination benefits | $ 0.0 | $ 0.0 |  |
Contributions to plans in next year |  |  |  | $ 3.5
Wolf Creek |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Jointly owned utility plant, proportionate ownership share | 94.00% |  | 94.00% |
Wolf Creek | Evergy Kansas South Inc |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Jointly owned utility plant, proportionate ownership share |  |  | 47.00% |
Wolf Creek | Evergy Kansas Central |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Jointly owned utility plant, proportionate ownership share | Rate | 47.00% |  |  |
Wolf Creek | Evergy Metro |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Jointly owned utility plant, proportionate ownership share | 47.00% |  | 47.00% |

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