ORGANIZATION AND BASIS OF PRESENTATION - Organization (Details) customer in Millions, $ in Millions			3 Months Ended		9 Months Ended		20 Months Ended
	Aug. 09, 2022 USD ($) MW	Oct. 01, 2021 USD ($)	Sep. 30, 2022 USD ($) MW	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) segment subsidiary kilovolt_line customer mi MW	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) MW	Dec. 31, 2021 USD ($)
Summary Of Accounting Policies [Line Items]
Owned generating capacity and renewable purchased power | MW			15,400		15,400		15,400
Number of customers served | customer					1.7
Number of segments | segment					1
Amortization of regulatory asset					$ 7.1
Estimated impairment loss on Sibley Unit 3			$ 6.0	$ 0.0	6.0	$ 0.0
Increase of Natural Gas and Purchased Power Costs, Net Increase in Wholesale Revenues						349.7	$ 367.9
Cash settlements under share forward agreement					15.1
Equity investment loss, net of derivative gain					16.3
Deferral of revenues to regulatory liability for refund to customers for return on investment of retired Sibley Station			47.5		47.5
2022OklahomaWindFarmPurchase [Member]
Summary Of Accounting Policies [Line Items]
Asset Acquisition, Price of Acquisition, Expected	$ 250.0
ApproximateMWNameplateCapacity | MW	199
Retired generation facilities
Summary Of Accounting Policies [Line Items]
Regulatory assets			25.6		25.6		25.6	$ 123.4
2022EstimatedPretaxLossOnAbandonment
Summary Of Accounting Policies [Line Items]
Estimated impairment loss on Sibley Unit 3			$ 6.0		$ 6.0
Prairie Wind Transmission, LLC
Summary Of Accounting Policies [Line Items]
Transmission line length | mi					108
Transmission line electrical potential | kilovolt_line					345
Evergy Kansas Central
Summary Of Accounting Policies [Line Items]
Increase of Natural Gas and Purchased Power Costs, Gross						127.9	134.3
Increase of Energy Marketing Margins				$ 95.0
Evergy Missouri West
Summary Of Accounting Policies [Line Items]
Increase of Natural Gas and Purchased Power Costs, Gross						293.4	296.6
Evergy Metro
Summary Of Accounting Policies [Line Items]
Increase in Wholesale Revenues						$ 71.6	$ 63.0
Evergy Kansas South Inc | Evergy Kansas Central
Summary Of Accounting Policies [Line Items]
Number of active wholly owned subsidiaries | subsidiary					1
Transource Energy, LLC | Evergy Transmission Company LLC
Summary Of Accounting Policies [Line Items]
Ownership percentage			13.50%		13.50%		13.50%
Transource Energy, LLC | AEP Transmission Holding Company, LLC
Summary Of Accounting Policies [Line Items]
Ownership interest			86.50%		86.50%		86.50%
Prairie Wind Transmission, LLC | Evergy Kansas Central
Summary Of Accounting Policies [Line Items]
Ownership percentage			50.00%		50.00%		50.00%
Early-Stage Energy Solution Company
Summary Of Accounting Policies [Line Items]
Initial Investment On Equity Investment		$ 3.7
Equity investment fair value								$ 31.4