REVENUE (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 1,167.4	$ 1,462.4
Other	56.5	149.5
Revenues	1,223.9	1,611.9
Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	604.4	784.1
Other	9.5	117.0
Revenues	613.9	901.1
Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	376.2	483.9
Other	46.3	32.3
Revenues	422.5	516.2
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	451.8	396.7
Residential | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	196.1	183.4
Residential | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	159.9	122.2
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	403.1	346.0
Commercial | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	165.2	153.7
Commercial | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	173.6	132.5
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	150.3	133.6
Industrial | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	100.8	93.0
Industrial | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	28.8	22.3
Other retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	9.0	7.4
Other retail | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4.1	3.2
Other retail | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2.6	2.1
Total electric retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,014.2	883.7
Total electric retail | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	466.2	433.3
Total electric retail | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	364.9	279.1
Wholesale
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	51.9	487.5
Wholesale | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	50.1	272.4
Wholesale | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	7.7	200.5
Transmission
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	98.0	86.0
Transmission | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	87.5	77.9
Transmission | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5.4	4.0
Industrial steam and other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3.3	5.2
Industrial steam and other | Evergy Kansas Central
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0.6	0.5
Industrial steam and other | Evergy Metro
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ (1.8)	$ 0.3