PENSION PLANS AND POST-RETIREMENT BENEFITS - Fair Values of Assets (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 1,409.2	$ 1,714.7	$ 1,799.1
Post-Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	192.9	242.3	248.3
Evergy Kansas Central | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	668.5	835.7	887.0
Evergy Kansas Central | Pension Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	530.8	717.8
Evergy Kansas Central | Pension Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	137.7	117.9
Evergy Kansas Central | Pension Benefits | Domestic equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	156.8	209.9
Evergy Kansas Central | Pension Benefits | Domestic equities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	129.2	177.3
Evergy Kansas Central | Pension Benefits | Domestic equities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Domestic equities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Domestic equities | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27.6	32.6
Evergy Kansas Central | Pension Benefits | International equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	129.1	167.4
Evergy Kansas Central | Pension Benefits | International equities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	129.1	167.4
Evergy Kansas Central | Pension Benefits | International equities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | International equities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | International equities | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Bond funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	241.7	330.4
Evergy Kansas Central | Pension Benefits | Bond funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	241.7	330.4
Evergy Kansas Central | Pension Benefits | Bond funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Bond funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Bond funds | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Real estate investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	26.8	28.1
Evergy Kansas Central | Pension Benefits | Real estate investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Real estate investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Real estate investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Real estate investments | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	26.8	28.1
Evergy Kansas Central | Pension Benefits | Combination debt/equity/other fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	30.8	42.7
Evergy Kansas Central | Pension Benefits | Combination debt/equity/other fund | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	30.8	42.7
Evergy Kansas Central | Pension Benefits | Combination debt/equity/other fund | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Combination debt/equity/other fund | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Combination debt/equity/other fund | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Alternative investment funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	63.9	44.1
Evergy Kansas Central | Pension Benefits | Alternative investment funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Alternative investment funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Alternative investment funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Alternative investment funds | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	63.9	44.1
Evergy Kansas Central | Pension Benefits | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19.4	13.1
Evergy Kansas Central | Pension Benefits | Short-term investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Short-term investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Short-term investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Pension Benefits | Short-term investments | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19.4	13.1
Evergy Kansas Central | Post-Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	96.2	124.0	125.8
Evergy Kansas Central | Post-Retirement Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	95.2	123.0
Evergy Kansas Central | Post-Retirement Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	1.0
Evergy Kansas Central | Post-Retirement Benefits | Domestic equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24.2	32.5
Evergy Kansas Central | Post-Retirement Benefits | Domestic equities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24.2	32.5
Evergy Kansas Central | Post-Retirement Benefits | Domestic equities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Domestic equities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Domestic equities | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | International equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17.5	22.1
Evergy Kansas Central | Post-Retirement Benefits | International equities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17.5	22.1
Evergy Kansas Central | Post-Retirement Benefits | International equities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | International equities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | International equities | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Bond funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	48.7	62.3
Evergy Kansas Central | Post-Retirement Benefits | Bond funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	48.7	62.3
Evergy Kansas Central | Post-Retirement Benefits | Bond funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Bond funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Bond funds | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Combination debt/equity/other fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4.8	6.1
Evergy Kansas Central | Post-Retirement Benefits | Combination debt/equity/other fund | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4.8	6.1
Evergy Kansas Central | Post-Retirement Benefits | Combination debt/equity/other fund | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Combination debt/equity/other fund | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Combination debt/equity/other fund | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	1.0
Evergy Kansas Central | Post-Retirement Benefits | Short-term investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Short-term investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Short-term investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Kansas Central | Post-Retirement Benefits | Short-term investments | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0	1.0
Evergy Metro | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	740.7	879.0	912.1
Evergy Metro | Pension Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	549.0	698.2
Evergy Metro | Pension Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	34.4	44.4
Evergy Metro | Pension Benefits | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	157.3	136.4
Evergy Metro | Pension Benefits | Domestic equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	156.1	203.0
Evergy Metro | Pension Benefits | Domestic equities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	135.5	179.5
Evergy Metro | Pension Benefits | Domestic equities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Domestic equities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Domestic equities | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20.6	23.5
Evergy Metro | Pension Benefits | International equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	136.7	193.1
Evergy Metro | Pension Benefits | International equities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	136.7	193.1
Evergy Metro | Pension Benefits | International equities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | International equities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | International equities | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Bond funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	195.2	260.6
Evergy Metro | Pension Benefits | Bond funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	195.2	260.6
Evergy Metro | Pension Benefits | Bond funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Bond funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Bond funds | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	23.7	27.1
Evergy Metro | Pension Benefits | Corporate bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Corporate bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	23.7	27.1
Evergy Metro | Pension Benefits | Corporate bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Corporate bonds | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | U.S. Treasury and agency bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14.0	14.5
Evergy Metro | Pension Benefits | U.S. Treasury and agency bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5.8	4.7
Evergy Metro | Pension Benefits | U.S. Treasury and agency bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8.2	9.8
Evergy Metro | Pension Benefits | U.S. Treasury and agency bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | U.S. Treasury and agency bonds | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Mortgage and asset backed securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5.0	4.3
Evergy Metro | Pension Benefits | Mortgage and asset backed securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Mortgage and asset backed securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5.0	4.3
Evergy Metro | Pension Benefits | Mortgage and asset backed securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Mortgage and asset backed securities | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Real estate investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	59.0	55.9
Evergy Metro | Pension Benefits | Real estate investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Real estate investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Real estate investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Real estate investments | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	59.0	55.9
Evergy Metro | Pension Benefits | Combination debt/equity/other fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	31.2	46.2
Evergy Metro | Pension Benefits | Combination debt/equity/other fund | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	31.2	46.2
Evergy Metro | Pension Benefits | Combination debt/equity/other fund | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Combination debt/equity/other fund | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Combination debt/equity/other fund | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Alternative investment funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	63.1	47.5
Evergy Metro | Pension Benefits | Alternative investment funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Alternative investment funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Alternative investment funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Alternative investment funds | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	63.1	47.5
Evergy Metro | Pension Benefits | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	44.6	14.1
Evergy Metro | Pension Benefits | Cash and cash equivalents | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	44.6	14.1
Evergy Metro | Pension Benefits | Cash and cash equivalents | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Cash and cash equivalents | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Cash and cash equivalents | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14.6	9.5
Evergy Metro | Pension Benefits | Short-term investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Short-term investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Short-term investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Short-term investments | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14.6	9.5
Evergy Metro | Pension Benefits | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(2.5)	3.2
Evergy Metro | Pension Benefits | Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(2.5)	3.2
Evergy Metro | Pension Benefits | Other | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Pension Benefits | Other | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	96.7	118.3	$ 122.5
Evergy Metro | Post-Retirement Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	74.3	93.0
Evergy Metro | Post-Retirement Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22.4	25.2
Evergy Metro | Post-Retirement Benefits | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.1
Evergy Metro | Post-Retirement Benefits | Domestic equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18.7	20.0
Evergy Metro | Post-Retirement Benefits | Domestic equities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18.7	20.0
Evergy Metro | Post-Retirement Benefits | Domestic equities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Domestic equities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Domestic equities | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | International equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11.6	12.3
Evergy Metro | Post-Retirement Benefits | International equities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11.6	12.3
Evergy Metro | Post-Retirement Benefits | International equities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | International equities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | International equities | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Bond funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	34.9	50.2
Evergy Metro | Post-Retirement Benefits | Bond funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	34.9	50.2
Evergy Metro | Post-Retirement Benefits | Bond funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Bond funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Bond funds | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14.6	18.1
Evergy Metro | Post-Retirement Benefits | Corporate bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Corporate bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14.6	18.1
Evergy Metro | Post-Retirement Benefits | Corporate bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Corporate bonds | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | U.S. Treasury and agency bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12.3	12.1
Evergy Metro | Post-Retirement Benefits | U.S. Treasury and agency bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6.0	6.1
Evergy Metro | Post-Retirement Benefits | U.S. Treasury and agency bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6.3	6.0
Evergy Metro | Post-Retirement Benefits | U.S. Treasury and agency bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | U.S. Treasury and agency bonds | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Mortgage and asset backed securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.3	0.8
Evergy Metro | Post-Retirement Benefits | Mortgage and asset backed securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Mortgage and asset backed securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.3	0.8
Evergy Metro | Post-Retirement Benefits | Mortgage and asset backed securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Mortgage and asset backed securities | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Combination debt/equity/other fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2.9	3.9
Evergy Metro | Post-Retirement Benefits | Combination debt/equity/other fund | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2.9	3.9
Evergy Metro | Post-Retirement Benefits | Combination debt/equity/other fund | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Combination debt/equity/other fund | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Combination debt/equity/other fund | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.2	0.5
Evergy Metro | Post-Retirement Benefits | Cash and cash equivalents | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.2	0.5
Evergy Metro | Post-Retirement Benefits | Cash and cash equivalents | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Cash and cash equivalents | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Cash and cash equivalents | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0.1
Evergy Metro | Post-Retirement Benefits | Short-term investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0.0
Evergy Metro | Post-Retirement Benefits | Short-term investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0.0
Evergy Metro | Post-Retirement Benefits | Short-term investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0.0
Evergy Metro | Post-Retirement Benefits | Short-term investments | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0.1
Evergy Metro | Post-Retirement Benefits | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.2	0.3
Evergy Metro | Post-Retirement Benefits | Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.2	0.3
Evergy Metro | Post-Retirement Benefits | Other | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Evergy Metro | Post-Retirement Benefits | Other | Assets measured at NAV
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0.0	$ 0.0