REVENUE (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 1,846.7	$ 1,580.1	$ 4,360.8	$ 4,250.6
Other	62.4	36.4	218.7	214.0
Revenues	1,909.1	1,616.5	4,579.5	4,464.6
Deferral of revenues to regulatory liability for refund to customers for return on investment of retired Sibley Station	47.5		47.5
Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	997.2	769.1	2,307.6	2,145.9
Other	24.2	8.7	51.7	131.5
Revenues	1,021.4	777.8	2,359.3	2,277.4
Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	604.1	544.6	1,398.8	1,445.4
Other	37.7	27.2	165.6	81.3
Revenues	641.8	571.8	1,564.4	1,526.7
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	746.6	677.4	1,711.8	1,533.9
Residential | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	343.1	282.3	762.0	657.3
Residential | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	255.9	254.5	600.7	550.6
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	583.7	525.0	1,452.3	1,293.5
Commercial | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	267.0	218.0	625.9	536.8
Commercial | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	222.0	221.9	589.7	542.5
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	197.2	166.0	517.6	449.6
Industrial | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	134.0	105.0	346.7	293.0
Industrial | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	36.6	35.9	98.8	91.9
Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	(39.0)	9.2	(20.2)	26.1
Deferral of revenues to regulatory liability for refund to customers for return on investment of retired Sibley Station	47.5		47.5
Other retail | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4.6	4.5	13.2	12.9
Other retail | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3.0	2.8	8.6	7.7
Total electric retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,488.5	1,377.6	3,661.5	3,303.1
Total electric retail | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	748.7	609.8	1,747.8	1,500.0
Total electric retail | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	517.5	515.1	1,297.8	1,192.7
Wholesale
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	250.6	105.0	382.0	662.5
Wholesale | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	156.9	76.8	288.4	402.7
Wholesale | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	81.4	24.0	86.6	237.3
Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	101.3	90.3	300.3	266.7
Transmission | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	91.2	81.9	269.8	241.5
Transmission | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4.6	4.3	14.4	12.8
Industrial steam and other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	6.3	7.2	17.0	18.3
Industrial steam and other | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0.4	0.6	1.6	1.7
Industrial steam and other | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 0.6	$ 1.2	$ 0.0	$ 2.6