FAIR VALUE MEASUREMENTS - NAV (Details) $ in Millions	9 Months Ended
	Sep. 30, 2022 USD ($) fund extension	Dec. 31, 2021 USD ($)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	$ 1.5	$ 1.7
Evergy Kansas Central | Alternative investments fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	0.0	0.0
Evergy Kansas Central | Real estate securities fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	0.0	0.0
Domestic | Evergy Kansas Central | Equity securities
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	$ 1.5	1.7
NAV, number of funds | fund	5
NAV, number of funds making distributions | fund	3
Domestic | Evergy Kansas Central | Equity Securities - Fourth Fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Length of settlement	15 years
NAV, number of extensions | extension	3
NAV, extension term	1 year
Domestic | Evergy Kansas Central | Equity Securities - Fifth Fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Length of settlement	15 years
Fair Value, Measurements, Recurring
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	$ 613.5	768.7
Total rabbi trust	34.9	44.2
Total Assets	660.8	856.8
Fair Value, Measurements, Recurring | Evergy Kansas Central
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	300.5	368.4
Total rabbi trust	24.2	31.7
Total Assets	324.7	400.1
Fair Value, Measurements, Recurring | Evergy Kansas Central | Alternative investments fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	32.2	32.7
Fair Value, Measurements, Recurring | Evergy Kansas Central | Real estate securities fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	18.6	15.2
Fair Value, Measurements, Recurring | Evergy Kansas Central | Core bond fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	50.2	58.1
Fair Value, Measurements, Recurring | Evergy Kansas Central | Combination debt/equity/other fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total rabbi trust	1.9	2.4
Fair Value, Measurements, Recurring | Other Evergy
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total rabbi trust		12.5
Total Assets	10.7	43.9
Fair Value, Measurements, Recurring | Other Evergy | Core bond fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total rabbi trust	10.5	12.5
Fair Value, Measurements, Recurring | Domestic | Evergy Kansas Central | Equity securities
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	106.0	140.4
NAV | Fair Value, Measurements, Recurring
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	63.8	61.8
Total rabbi trust	0.0	0.0
Total Assets	63.8	61.8
NAV | Fair Value, Measurements, Recurring | Evergy Kansas Central
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	63.8	61.8
Total rabbi trust	0.0	0.0
Total Assets	63.8	61.8
NAV | Fair Value, Measurements, Recurring | Evergy Kansas Central | Alternative investments fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	$ 32.2	32.7
Length of Settlement	65 days
NAV | Fair Value, Measurements, Recurring | Evergy Kansas Central | Real estate securities fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	$ 18.6	15.2
Length of Settlement	65 days
NAV | Fair Value, Measurements, Recurring | Evergy Kansas Central | Core bond fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	$ 0.0	0.0
NAV | Fair Value, Measurements, Recurring | Evergy Kansas Central | Combination debt/equity/other fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total rabbi trust	0.0	0.0
NAV | Fair Value, Measurements, Recurring | Other Evergy
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total rabbi trust		0.0
Total Assets	0.0	0.0
NAV | Fair Value, Measurements, Recurring | Other Evergy | Core bond fund
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total rabbi trust	0.0	0.0
NAV | Fair Value, Measurements, Recurring | Domestic | Evergy Kansas Central | Equity securities
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	$ 13.0	$ 13.9