Consolidated Statements of Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
OPERATING REVENUES	$ 1,184.7	$ 1,221.7	$ 2,301.4	$ 2,438.6
OPERATING EXPENSES:
Fuel and purchased power	258.1	291.6	516.3	621.6
SPP network transmission costs	69.7	62.8	131.7	126.3
Operating and maintenance	272.7	288.6	560.9	595.5
Depreciation and amortization	221.6	215.4	440.1	429.0
Taxes other than income tax	90.9	91.6	183.2	184.9
Total Operating Expenses	913.0	950.0	1,832.2	1,957.3
INCOME FROM OPERATIONS	271.7	271.7	469.2	481.3
OTHER INCOME (EXPENSE):
Investment earnings	3.1	2.6	2.3	5.8
Other income	7.6	6.1	9.9	14.3
Other expense	(14.9)	(18.1)	(37.6)	(37.5)
Total Other Expense, Net	(4.2)	(9.4)	(25.4)	(17.4)
Interest expense	99.5	95.4	195.7	186.5
INCOME BEFORE INCOME TAXES	168.0	166.9	248.1	277.4
Income tax expense	33.7	24.4	43.8	33.7
Equity in earnings of equity method investees, net of income taxes	2.0	2.1	4.2	4.3
NET INCOME	136.3	144.6	208.5	248.0
Less: Net income attributable to noncontrolling interests	2.9	4.9	5.7	8.8
Net income attributable to Evergy, Inc.	$ 133.4	$ 139.7	$ 202.8	$ 239.2
BASIC AND DILUTED EARNINGS PER AVERAGE COMMON SHARE OUTSTANDING ATTRIBUTABLE TO EVERGY, INC. (see Note 1)
Basic earnings per common share (in dollars per share)	$ 0.59	$ 0.57	$ 0.89	$ 0.96
Diluted earnings per common share (in dollars per share)	$ 0.59	$ 0.57	$ 0.89	$ 0.96
AVERAGE COMMON SHARES OUTSTANDING
Basic (in shares)	227.2	243.2	227.1	248.0
Diluted (in shares)	227.6	243.4	227.6	248.2
COMPREHENSIVE INCOME
Net income	$ 136.3	$ 144.6	$ 208.5	$ 248.0
Derivative hedging activity
Loss on derivative hedging instruments	0.0	(21.2)	0.0	(35.0)
Income tax benefit	0.0	5.4	0.0	9.0
Net loss on derivative hedging instruments	0.0	(15.8)	0.0	(26.0)
Reclassification to expenses, net of tax	(1.0)	0.0	0.3	0.0
Derivative hedging activity, net of tax	(1.0)	(15.8)	0.3	(26.0)
Defined benefit pension plans
Amortization of net losses included in net periodic benefit costs, net of tax	(0.1)	0.0	(0.1)	0.0
Change in unrecognized pension expense, net of tax	(0.1)	0.0	(0.1)	0.0
Total other comprehensive income (loss)	(1.1)	(15.8)	0.2	(26.0)
COMPREHENSIVE INCOME	135.2	128.8	208.7	222.0
Less: comprehensive income attributable to noncontrolling interest	2.9	4.9	5.7	8.8
COMPREHENSIVE INCOME	$ 132.3	$ 123.9	$ 203.0	$ 213.2