FAIR VALUE MEASUREMENTS - NAV (Details) $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($) extension fund	Dec. 31, 2022 USD ($)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	$ 1.5	$ 1.5
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	1.5
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	$ 711.2	653.3
Total rabbi trust	31.5	34.1
Total Assets	805.1	748.9
Fair Value, Measurements, Recurring | Evergy Kansas Central
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	347.6	318.8
Total rabbi trust	23.1	24.9
Total Assets	415.4	393.6
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	35.1	31.8
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	17.3	18.9
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	53.2	51.0
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	1.7	1.9
Fair Value, Measurements, Recurring | Other Evergy
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total rabbi trust	8.4	9.2
Total Assets	12.2	9.6
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	8.4	9.2
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	128.3	112.5
NAV | Fair Value, Measurements, Recurring
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	62.9	62.8
Total rabbi trust	0.0	0.0
Total Assets	62.9	62.8
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	62.9	62.8
Total rabbi trust	0.0	0.0
Total Assets	62.9	62.8
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	$ 35.1	31.8
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	$ 17.3	18.9
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	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	$ 10.5	$ 12.1