Consolidated Statements of Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
OPERATING REVENUES	$ 1,577.6	$ 1,582.5	$ 4,016.2	$ 3,076.1
OPERATING EXPENSES:
Fuel and purchased power	357.3	383.7	978.9	748.9
SPP network transmission costs	62.4	58.4	188.7	194.4
Operating and maintenance	311.6	330.4	907.1	754.2
Depreciation and amortization	216.1	193.9	645.1	411.6
Taxes other than income tax	91.5	83.0	276.4	183.5
Total Operating Expenses	1,038.9	1,049.4	2,996.2	2,292.6
INCOME FROM OPERATIONS	538.7	533.1	1,020.0	783.5
OTHER INCOME (EXPENSE):
Investment earnings	1.8	4.9	7.6	6.2
Other income	2.8	1.6	17.1	5.3
Other expense	(19.7)	(30.8)	(57.2)	(55.2)
Total Other Expense, Net	(15.1)	(24.3)	(32.5)	(43.7)
Interest expense	90.8	89.1	277.3	191.3
INCOME BEFORE INCOME TAXES	432.8	419.7	710.2	548.5
Income tax expense	65.5	64.1	99.2	28.3
Equity in earnings of equity method investees, net of income taxes	3.6	2.0	7.9	4.7
NET INCOME	370.9	357.6	618.9	524.9
Less: Net income attributable to noncontrolling interests	4.1	2.6	12.9	7.6
Net income attributable to Evergy, Inc.	$ 366.8	$ 355.0	$ 606.0	$ 517.3
BASIC AND DILUTED EARNINGS PER AVERAGE COMMON SHARE OUTSTANDING ATTRIBUTABLE TO EVERGY (see Note 1)
Earnings Per Share, Basic	$ 1.56	$ 1.32	$ 2.49	$ 2.61
Diluted earnings per common share (in dollars per share)	$ 1.56	$ 1.32	$ 2.49	$ 2.61
AVERAGE COMMON SHARES OUTSTANDING
Basic (in shares)	234.6	268.6	243.5	197.9
Diluted (in shares)	235.0	268.8	243.8	198.0
COMPREHENSIVE INCOME
Net income	$ 370.9	$ 357.6	$ 618.9	$ 524.9
Derivative hedging activity
Loss on derivative hedging instruments	(29.4)	0.0	(64.4)	0.0
Income tax benefit	7.5	0.0	16.5	0.0
Net loss on derivative hedging instruments	(21.9)	0.0	(47.9)	0.0
Reclassification to expenses, net of tax	0.2	0.0	0.2	0.0
Derivative hedging activity, net of tax	(21.7)	0.0	(47.7)	0.0
Total other comprehensive loss	(21.7)	0.0	(47.7)	0.0
COMPREHENSIVE INCOME	349.2	357.6	571.2	524.9
Less: comprehensive income attributable to noncontrolling interest	4.1	2.6	12.9	7.6
COMPREHENSIVE INCOME	$ 345.1	$ 355.0	$ 558.3	$ 517.3