ORGANIZATION AND BASIS OF PRESENTATION - Other Income And Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Entity Information [Line Items]
Non-service cost component of net benefit cost	$ (6.4)	$ (10.2)	$ (37.2)	$ (46.5)
Other	(6.4)	(6.5)	(17.9)	(18.0)
Other expense	(12.8)	(16.7)	(55.1)	(64.5)
Evergy Kansas Central
Entity Information [Line Items]
Non-service cost component of net benefit cost	(4.5)	(4.2)	(12.7)	(13.6)
Other	(5.7)	(6.3)	(16.1)	(16.2)
Other expense	(10.2)	(10.5)	(28.8)	(29.8)
Evergy Metro
Entity Information [Line Items]
Non-service cost component of net benefit cost	(0.1)	(2.2)	(18.0)	(21.8)
Other	(0.4)	(0.3)	(1.3)	(1.3)
Other expense	$ (0.5)	$ (2.5)	$ (19.3)	$ (23.1)