FAIR VALUE MEASUREMENTS - NAV (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) fund	Dec. 31, 2023 USD ($)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	$ 1.4	$ 1.4
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	$ 1.4	1.4
NAV, number of funds | fund	5
Fair Value, Measurements, Recurring
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	$ 805.9	766.4
Total rabbi trust	32.3	33.3
Total Assets	903.6	858.1
Fair Value, Measurements, Recurring | Evergy Kansas Central
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	375.9	365.1
Total rabbi trust	23.8	24.5
Total Assets	443.8	430.5
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	40.1	37.9
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	16.6	17.2
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	56.2	56.2
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	1.7
Fair Value, Measurements, Recurring | Other Evergy
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total rabbi trust	8.5	8.8
Total Assets	10.4	10.6
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	8.5	8.8
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	140.8	133.1
NAV | Fair Value, Measurements, Recurring
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total nuclear decommissioning trust	66.5	64.9
Total rabbi trust	0.0	0.0
Total Assets	66.5	64.9
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	66.5	64.9
Total rabbi trust	0.0	0.0
Total Assets	66.5	64.9
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	$ 40.1	37.9
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	$ 16.6	17.2
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	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	$ 9.8	$ 9.8