FAIR VALUE MEASUREMENTS - Recurring (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets, Other	Other assets, Other
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other, Other	Other, Other
Fair Value, Measurements, Recurring
Assets
Total nuclear decommissioning trust	$ 805.9	$ 766.4
Total rabbi trust	32.3	33.3
Derivative Asset	47.6	42.7
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(42.2)	(90.3)
Total self-insured health plan trust	17.8	15.7
Total Assets	903.6	858.1
Derivative Liability	44.7	45.4
FIN 39 Derivative liability netting	(37.8)	(83.4)
Total Liabilities	44.7	45.4
Fair Value, Measurements, Recurring | Level 1
Assets
Total nuclear decommissioning trust	692.7	653.7
Total rabbi trust	32.3	33.3
Derivative Asset, Fair Value, Gross Asset	43.9	89.0
Total self-insured health plan trust	9.8	8.8
Total Assets	778.7	784.8
Derivative Liability, Fair Value, Gross Liability	38.9	82.0
Total Liabilities	38.9	82.0
Fair Value, Measurements, Recurring | Level 2
Assets
Total nuclear decommissioning trust	46.7	47.8
Total rabbi trust	0.0	0.0
Derivative Asset, Fair Value, Gross Asset	38.8	33.6
Total self-insured health plan trust	8.0	6.9
Total Assets	93.5	88.3
Derivative Liability, Fair Value, Gross Liability	42.0	36.9
Total Liabilities	42.0	36.9
Fair Value, Measurements, Recurring | Level 3
Assets
Total nuclear decommissioning trust	0.0	0.0
Total rabbi trust	0.0	0.0
Derivative Asset, Fair Value, Gross Asset	7.1	10.4
Total self-insured health plan trust	0.0	0.0
Total Assets	7.1	10.4
Derivative Liability, Fair Value, Gross Liability	1.6	9.9
Total Liabilities	1.6	9.9
Fair Value, Measurements, Recurring | NAV
Assets
Total nuclear decommissioning trust	66.5	64.9
Total rabbi trust	0.0	0.0
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Total self-insured health plan trust	0.0	0.0
Total Assets	66.5	64.9
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Total Liabilities	0.0	0.0
Fair Value, Measurements, Recurring | Power commodity contract
Assets
Derivative Asset	47.0	42.0
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(10.5)	(16.9)
Derivative Liability	42.4	43.9
FIN 39 Derivative liability netting	(6.2)	(10.0)
Fair Value, Measurements, Recurring | Power commodity contract | Level 1
Assets
Derivative Asset, Fair Value, Gross Asset	14.0	16.3
Derivative Liability, Fair Value, Gross Liability	7.3	9.4
Fair Value, Measurements, Recurring | Power commodity contract | Level 2
Assets
Derivative Asset, Fair Value, Gross Asset	36.4	32.2
Derivative Liability, Fair Value, Gross Liability	39.7	34.6
Fair Value, Measurements, Recurring | Power commodity contract | Level 3
Assets
Derivative Asset, Fair Value, Gross Asset	7.1	10.4
Derivative Liability, Fair Value, Gross Liability	1.6	9.9
Fair Value, Measurements, Recurring | Power commodity contract | NAV
Assets
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Fair Value, Measurements, Recurring | Natural gas commodity contract
Assets
Derivative Asset	0.6	0.7
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(31.7)	(73.4)
Derivative Liability	2.3	1.5
FIN 39 Derivative liability netting	(31.6)	(73.4)
Fair Value, Measurements, Recurring | Natural gas commodity contract | Level 1
Assets
Derivative Asset, Fair Value, Gross Asset	29.9	72.7
Derivative Liability, Fair Value, Gross Liability	31.6	72.6
Fair Value, Measurements, Recurring | Natural gas commodity contract | Level 2
Assets
Derivative Asset, Fair Value, Gross Asset	2.4	1.4
Derivative Liability, Fair Value, Gross Liability	2.3	2.3
Fair Value, Measurements, Recurring | Natural gas commodity contract | Level 3
Assets
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Fair Value, Measurements, Recurring | Natural gas commodity contract | NAV
Assets
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	$ 0.0	$ 0.0
Evergy Kansas Central
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets, Other	Other assets, Other
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other, Other	Other, Other
Evergy Kansas Central | Fair Value, Measurements, Recurring
Assets
Total nuclear decommissioning trust	$ 375.9	$ 365.1
Total rabbi trust	23.8	24.5
Derivative Asset	44.1	40.9
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(41.0)	(87.2)
Total Assets	443.8	430.5
Derivative Liability	44.7	40.7
FIN 39 Derivative liability netting	(36.6)	(80.3)
Total Liabilities	44.7	40.7
Evergy Kansas Central | Fair Value, Measurements, Recurring | Core bond fund
Assets
Total nuclear decommissioning trust	56.2	56.2
Evergy Kansas Central | Fair Value, Measurements, Recurring | High-yield bond fund
Assets
Total nuclear decommissioning trust	29.5	29.1
Evergy Kansas Central | Fair Value, Measurements, Recurring | Emerging markets bond fund
Assets
Total nuclear decommissioning trust	18.2	18.3
Evergy Kansas Central | Fair Value, Measurements, Recurring | Combination debt/equity/other fund
Assets
Total rabbi trust	1.7	1.7
Evergy Kansas Central | Fair Value, Measurements, Recurring | Alternative investments fund
Assets
Total nuclear decommissioning trust	40.1	37.9
Evergy Kansas Central | Fair Value, Measurements, Recurring | Real estate securities fund
Assets
Total nuclear decommissioning trust	16.6	17.2
Evergy Kansas Central | Fair Value, Measurements, Recurring | Cash equivalents
Assets
Total nuclear decommissioning trust	0.5	0.7
Total rabbi trust	0.2	0.2
Evergy Kansas Central | Fair Value, Measurements, Recurring | Equity funds
Assets
Total rabbi trust	7.2	7.4
Evergy Kansas Central | Fair Value, Measurements, Recurring | Fixed income funds
Assets
Total rabbi trust	14.7	15.2
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 1
Assets
Total nuclear decommissioning trust	309.4	300.2
Total rabbi trust	23.8	24.5
Derivative Asset, Fair Value, Gross Asset	43.9	89.0
Total Assets	377.1	413.7
Derivative Liability, Fair Value, Gross Liability	38.9	82.0
Total Liabilities	38.9	82.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 1 | Core bond fund
Assets
Total nuclear decommissioning trust	56.2	56.2
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 1 | High-yield bond fund
Assets
Total nuclear decommissioning trust	29.5	29.1
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 1 | Emerging markets bond fund
Assets
Total nuclear decommissioning trust	18.2	18.3
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 1 | Combination debt/equity/other fund
Assets
Total rabbi trust	1.7	1.7
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 1 | Alternative investments fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 1 | Real estate securities fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 1 | Cash equivalents
Assets
Total nuclear decommissioning trust	0.5	0.7
Total rabbi trust	0.2	0.2
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 1 | Equity funds
Assets
Total rabbi trust	7.2	7.4
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 1 | Fixed income funds
Assets
Total rabbi trust	14.7	15.2
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 2
Assets
Total nuclear decommissioning trust	0.0	0.0
Total rabbi trust	0.0	0.0
Derivative Asset, Fair Value, Gross Asset	38.8	33.6
Total Assets	38.8	33.6
Derivative Liability, Fair Value, Gross Liability	42.0	35.8
Total Liabilities	42.0	35.8
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 2 | Core bond fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 2 | High-yield bond fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 2 | Emerging markets bond fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 2 | Combination debt/equity/other fund
Assets
Total rabbi trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 2 | Alternative investments fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 2 | Real estate securities fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 2 | Cash equivalents
Assets
Total nuclear decommissioning trust	0.0	0.0
Total rabbi trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 2 | Equity funds
Assets
Total rabbi trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 2 | Fixed income funds
Assets
Total rabbi trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 3
Assets
Total nuclear decommissioning trust	0.0	0.0
Total rabbi trust	0.0	0.0
Derivative Asset, Fair Value, Gross Asset	2.4	5.5
Total Assets	2.4	5.5
Derivative Liability, Fair Value, Gross Liability	0.4	3.2
Total Liabilities	0.4	3.2
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 3 | Core bond fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 3 | High-yield bond fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 3 | Emerging markets bond fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 3 | Combination debt/equity/other fund
Assets
Total rabbi trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 3 | Alternative investments fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 3 | Real estate securities fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 3 | Cash equivalents
Assets
Total nuclear decommissioning trust	0.0	0.0
Total rabbi trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 3 | Equity funds
Assets
Total rabbi trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Level 3 | Fixed income funds
Assets
Total rabbi trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | NAV
Assets
Total nuclear decommissioning trust	66.5	64.9
Total rabbi trust	0.0	0.0
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Total Assets	66.5	64.9
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Total Liabilities	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | NAV | Core bond fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | NAV | High-yield bond fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | NAV | Emerging markets bond fund
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | NAV | Combination debt/equity/other fund
Assets
Total rabbi trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | NAV | Alternative investments fund
Assets
Total nuclear decommissioning trust	40.1	37.9
Evergy Kansas Central | Fair Value, Measurements, Recurring | NAV | Real estate securities fund
Assets
Total nuclear decommissioning trust	16.6	17.2
Evergy Kansas Central | Fair Value, Measurements, Recurring | NAV | Cash equivalents
Assets
Total nuclear decommissioning trust	0.0	0.0
Total rabbi trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | NAV | Equity funds
Assets
Total rabbi trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | NAV | Fixed income funds
Assets
Total rabbi trust	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Power commodity contract
Assets
Derivative Asset	43.5	40.2
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(9.3)	(13.8)
Derivative Liability	42.4	40.3
FIN 39 Derivative liability netting	(5.0)	(6.9)
Evergy Kansas Central | Fair Value, Measurements, Recurring | Power commodity contract | Level 1
Assets
Derivative Asset, Fair Value, Gross Asset	14.0	16.3
Derivative Liability, Fair Value, Gross Liability	7.3	9.4
Evergy Kansas Central | Fair Value, Measurements, Recurring | Power commodity contract | Level 2
Assets
Derivative Asset, Fair Value, Gross Asset	36.4	32.2
Derivative Liability, Fair Value, Gross Liability	39.7	34.6
Evergy Kansas Central | Fair Value, Measurements, Recurring | Power commodity contract | Level 3
Assets
Derivative Asset, Fair Value, Gross Asset	2.4	5.5
Derivative Liability, Fair Value, Gross Liability	0.4	3.2
Evergy Kansas Central | Fair Value, Measurements, Recurring | Power commodity contract | NAV
Assets
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Natural gas commodity contract
Assets
Derivative Asset	0.6	0.7
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(31.7)	(73.4)
Derivative Liability	2.3	0.4
FIN 39 Derivative liability netting	(31.6)	(73.4)
Evergy Kansas Central | Fair Value, Measurements, Recurring | Natural gas commodity contract | Level 1
Assets
Derivative Asset, Fair Value, Gross Asset	29.9	72.7
Derivative Liability, Fair Value, Gross Liability	31.6	72.6
Evergy Kansas Central | Fair Value, Measurements, Recurring | Natural gas commodity contract | Level 2
Assets
Derivative Asset, Fair Value, Gross Asset	2.4	1.4
Derivative Liability, Fair Value, Gross Liability	2.3	1.2
Evergy Kansas Central | Fair Value, Measurements, Recurring | Natural gas commodity contract | Level 3
Assets
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Evergy Kansas Central | Fair Value, Measurements, Recurring | Natural gas commodity contract | NAV
Assets
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Evergy Kansas Central | Domestic | Fair Value, Measurements, Recurring | Equity securities
Assets
Total nuclear decommissioning trust	140.8	133.1
Evergy Kansas Central | Domestic | Fair Value, Measurements, Recurring | Level 1 | Equity securities
Assets
Total nuclear decommissioning trust	131.0	123.3
Evergy Kansas Central | Domestic | Fair Value, Measurements, Recurring | Level 2 | Equity securities
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Domestic | Fair Value, Measurements, Recurring | Level 3 | Equity securities
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | Domestic | Fair Value, Measurements, Recurring | NAV | Equity securities
Assets
Total nuclear decommissioning trust	9.8	9.8
Evergy Kansas Central | International | Fair Value, Measurements, Recurring | Equity securities
Assets
Total nuclear decommissioning trust	74.0	72.6
Evergy Kansas Central | International | Fair Value, Measurements, Recurring | Level 1 | Equity securities
Assets
Total nuclear decommissioning trust	74.0	72.6
Evergy Kansas Central | International | Fair Value, Measurements, Recurring | Level 2 | Equity securities
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | International | Fair Value, Measurements, Recurring | Level 3 | Equity securities
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Kansas Central | International | Fair Value, Measurements, Recurring | NAV | Equity securities
Assets
Total nuclear decommissioning trust	$ 0.0	$ 0.0
Evergy Metro
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets, Other	Other assets, Other
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other, Other	Other, Other
Evergy Metro | Fair Value, Measurements, Recurring
Assets
Total nuclear decommissioning trust	$ 430.0	$ 401.3
Derivative Asset	1.6	0.0
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(1.0)	(2.1)
Total self-insured health plan trust	17.8	15.7
Total Assets	449.4	417.0
Derivative Liability	0.0	3.6
FIN 39 Derivative liability netting	(1.0)	(2.1)
Total Liabilities	0.0	3.6
Evergy Metro | Fair Value, Measurements, Recurring | Equity securities
Assets
Total nuclear decommissioning trust	330.2	302.4
Total self-insured health plan trust	2.1	2.0
Evergy Metro | Fair Value, Measurements, Recurring | Cash equivalents
Assets
Total nuclear decommissioning trust	5.8	3.2
Evergy Metro | Fair Value, Measurements, Recurring | U.S. Treasury
Assets
Total nuclear decommissioning trust	47.3	47.9
Evergy Metro | Fair Value, Measurements, Recurring | State and local obligations
Assets
Total nuclear decommissioning trust	3.8	3.8
Evergy Metro | Fair Value, Measurements, Recurring | Corporate bonds
Assets
Total nuclear decommissioning trust	42.8	43.9
Evergy Metro | Fair Value, Measurements, Recurring | Foreign governments
Assets
Total nuclear decommissioning trust	0.1	0.1
Evergy Metro | Fair Value, Measurements, Recurring | Debt securities
Assets
Total self-insured health plan trust	10.9	9.4
Evergy Metro | Fair Value, Measurements, Recurring | Cash and cash equivalents
Assets
Total self-insured health plan trust	4.8	4.3
Evergy Metro | Fair Value, Measurements, Recurring | Level 1
Assets
Total nuclear decommissioning trust	383.3	353.5
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Total self-insured health plan trust	9.8	8.8
Total Assets	393.1	362.3
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Total Liabilities	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 1 | Equity securities
Assets
Total nuclear decommissioning trust	330.2	302.4
Total self-insured health plan trust	2.1	2.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 1 | Cash equivalents
Assets
Total nuclear decommissioning trust	5.8	3.2
Evergy Metro | Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury
Assets
Total nuclear decommissioning trust	47.3	47.9
Evergy Metro | Fair Value, Measurements, Recurring | Level 1 | State and local obligations
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 1 | Corporate bonds
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 1 | Foreign governments
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 1 | Debt securities
Assets
Total self-insured health plan trust	2.9	2.5
Evergy Metro | Fair Value, Measurements, Recurring | Level 1 | Cash and cash equivalents
Assets
Total self-insured health plan trust	4.8	4.3
Evergy Metro | Fair Value, Measurements, Recurring | Level 2
Assets
Total nuclear decommissioning trust	46.7	47.8
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Total self-insured health plan trust	8.0	6.9
Total Assets	54.7	54.7
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Total Liabilities	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 2 | Equity securities
Assets
Total nuclear decommissioning trust	0.0	0.0
Total self-insured health plan trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 2 | Cash equivalents
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 2 | State and local obligations
Assets
Total nuclear decommissioning trust	3.8	3.8
Evergy Metro | Fair Value, Measurements, Recurring | Level 2 | Corporate bonds
Assets
Total nuclear decommissioning trust	42.8	43.9
Evergy Metro | Fair Value, Measurements, Recurring | Level 2 | Foreign governments
Assets
Total nuclear decommissioning trust	0.1	0.1
Evergy Metro | Fair Value, Measurements, Recurring | Level 2 | Debt securities
Assets
Total self-insured health plan trust	8.0	6.9
Evergy Metro | Fair Value, Measurements, Recurring | Level 2 | Cash and cash equivalents
Assets
Total self-insured health plan trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 3
Assets
Total nuclear decommissioning trust	0.0	0.0
Derivative Asset, Fair Value, Gross Asset	2.6	2.1
Total self-insured health plan trust	0.0	0.0
Total Assets	2.6	2.1
Derivative Liability, Fair Value, Gross Liability	1.0	5.7
Total Liabilities	1.0	5.7
Evergy Metro | Fair Value, Measurements, Recurring | Level 3 | Equity securities
Assets
Total nuclear decommissioning trust	0.0	0.0
Total self-insured health plan trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 3 | Cash equivalents
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 3 | State and local obligations
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 3 | Corporate bonds
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 3 | Foreign governments
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 3 | Debt securities
Assets
Total self-insured health plan trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Level 3 | Cash and cash equivalents
Assets
Total self-insured health plan trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | NAV
Assets
Total nuclear decommissioning trust	0.0	0.0
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Total self-insured health plan trust	0.0	0.0
Total Assets	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Total Liabilities	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | NAV | Equity securities
Assets
Total nuclear decommissioning trust	0.0	0.0
Total self-insured health plan trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | NAV | Cash equivalents
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | NAV | U.S. Treasury
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | NAV | State and local obligations
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | NAV | Corporate bonds
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | NAV | Foreign governments
Assets
Total nuclear decommissioning trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | NAV | Debt securities
Assets
Total self-insured health plan trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | NAV | Cash and cash equivalents
Assets
Total self-insured health plan trust	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Power commodity contract
Assets
Derivative Asset	1.6	0.0
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(1.0)	(2.1)
Derivative Liability	0.0	3.6
FIN 39 Derivative liability netting	(1.0)	(2.1)
Evergy Metro | Fair Value, Measurements, Recurring | Power commodity contract | Level 1
Assets
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Power commodity contract | Level 2
Assets
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Evergy Metro | Fair Value, Measurements, Recurring | Power commodity contract | Level 3
Assets
Derivative Asset, Fair Value, Gross Asset	2.6	2.1
Derivative Liability, Fair Value, Gross Liability	1.0	5.7
Evergy Metro | Fair Value, Measurements, Recurring | Power commodity contract | NAV
Assets
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	$ 0.0	$ 0.0
Other Evergy
Assets
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets, Other	Other assets, Other
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other, Other	Other, Other
Other Evergy | Fair Value, Measurements, Recurring
Assets
Total rabbi trust	$ 8.5	$ 8.8
Derivative Asset	1.9	1.8
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(0.2)	(1.0)
Total Assets	10.4	10.6
Derivative Liability	0.0	1.1
FIN 39 Derivative liability netting	(0.2)	(1.0)
Total Liabilities	0.0	1.1
Other Evergy | Fair Value, Measurements, Recurring | Core bond fund
Assets
Total rabbi trust	8.5	8.8
Other Evergy | Fair Value, Measurements, Recurring | Level 1
Assets
Total rabbi trust	8.5	8.8
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Total Assets	8.5	8.8
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Total Liabilities	0.0	0.0
Other Evergy | Fair Value, Measurements, Recurring | Level 1 | Core bond fund
Assets
Total rabbi trust	8.5	8.8
Other Evergy | Fair Value, Measurements, Recurring | Level 2
Assets
Total rabbi trust	0.0	0.0
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Total Assets	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	0.0	1.1
Total Liabilities	0.0	1.1
Other Evergy | Fair Value, Measurements, Recurring | Level 2 | Core bond fund
Assets
Total rabbi trust	0.0	0.0
Other Evergy | Fair Value, Measurements, Recurring | Level 3
Assets
Total rabbi trust	0.0	0.0
Derivative Asset, Fair Value, Gross Asset	2.1	2.8
Total Assets	2.1	2.8
Derivative Liability, Fair Value, Gross Liability	0.2	1.0
Total Liabilities	0.2	1.0
Other Evergy | Fair Value, Measurements, Recurring | Level 3 | Core bond fund
Assets
Total rabbi trust	0.0	0.0
Other Evergy | Fair Value, Measurements, Recurring | NAV
Assets
Total rabbi trust	0.0	0.0
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Total Assets	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Total Liabilities	0.0	0.0
Other Evergy | Fair Value, Measurements, Recurring | NAV | Core bond fund
Assets
Total rabbi trust	0.0	0.0
Other Evergy | Fair Value, Measurements, Recurring | Power commodity contract
Assets
Derivative Asset	1.9	1.8
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(0.2)	(1.0)
Derivative Liability	0.0	0.0
FIN 39 Derivative liability netting	(0.2)	(1.0)
Other Evergy | Fair Value, Measurements, Recurring | Power commodity contract | Level 1
Assets
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Other Evergy | Fair Value, Measurements, Recurring | Power commodity contract | Level 2
Assets
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Other Evergy | Fair Value, Measurements, Recurring | Power commodity contract | Level 3
Assets
Derivative Asset, Fair Value, Gross Asset	2.1	2.8
Derivative Liability, Fair Value, Gross Liability	0.2	1.0
Other Evergy | Fair Value, Measurements, Recurring | Power commodity contract | NAV
Assets
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
Derivative Liability, Fair Value, Gross Liability	$ 0.0	0.0
Other Evergy | Fair Value, Measurements, Recurring | Natural gas commodity contract
Assets
Derivative Liability		1.1
FIN 39 Derivative liability netting		0.0
Other Evergy | Fair Value, Measurements, Recurring | Natural gas commodity contract | Level 1
Assets
Derivative Liability, Fair Value, Gross Liability		0.0
Other Evergy | Fair Value, Measurements, Recurring | Natural gas commodity contract | Level 2
Assets
Derivative Liability, Fair Value, Gross Liability		1.1
Other Evergy | Fair Value, Measurements, Recurring | Natural gas commodity contract | Level 3
Assets
Derivative Liability, Fair Value, Gross Liability		0.0
Other Evergy | Fair Value, Measurements, Recurring | Natural gas commodity contract | NAV
Assets
Derivative Liability, Fair Value, Gross Liability		$ 0.0