TAXES - Income Tax Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current Federal Tax Expense (Benefit)	$ 10.2	$ 5.0
Current State and Local Tax Expense (Benefit)	8.1	4.7
Current Income Tax Expense (Benefit), Total	18.3	9.7
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred Federal Income Tax Expense (Benefit)	(2.5)	7.7
Deferred State and Local Income Tax Expense (Benefit)	(6.7)	(3.3)
Deferred Income Tax Expense (Benefit), Total	(9.2)	4.4
Investment Tax Credits
Investment tax credit amortization	(1.8)	(1.7)
Income Tax Expense (Benefit), Total	$ 7.3	$ 12.4
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%
Effect Of [Abstract]
COLI policies	(1.20%)	(1.40%)
State income taxes	0.60%	0.60%
Flow through depreciation for plant-related differences	(8.30%)	(7.70%)
Federal tax credits	(6.60%)	(3.50%)
Non-controlling interest	(0.30%)	(0.30%)
AFUDC equity	(0.30%)	(0.60%)
Amortization of federal investment tax credits	(0.60%)	(0.60%)
Stock compensation	0.40%	0.10%
Officer compensation limitation	0.80%	0.20%
Other	0.10%	0.10%
Effective Income Tax Rate Reconciliation, Percent, Total	5.60%	7.90%
Evergy Kansas Central
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current Federal Tax Expense (Benefit)	$ 4.3	$ 18.1
Current State and Local Tax Expense (Benefit)	3.1	2.0
Current Income Tax Expense (Benefit), Total	7.4	20.1
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred Federal Income Tax Expense (Benefit)	(2.5)	(10.0)
Deferred State and Local Income Tax Expense (Benefit)	(1.8)	(0.7)
Deferred Income Tax Expense (Benefit), Total	(4.3)	(10.7)
Investment Tax Credits
Investment tax credit amortization	(1.0)	(1.0)
Income Tax Expense (Benefit), Total	$ 2.1	$ 8.4
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%
Effect Of [Abstract]
COLI policies	(2.00%)	(2.40%)
State income taxes	0.60%	0.70%
Flow through depreciation for plant-related differences	(5.40%)	(4.00%)
Federal tax credits	(10.90%)	(6.30%)
Non-controlling interest	(0.50%)	(0.50%)
AFUDC equity	(0.50%)	(0.50%)
Amortization of federal investment tax credits	(0.40%)	(0.40%)
Stock compensation	(0.10%)	(0.20%)
Other	0.10%	0.00%
Effective Income Tax Rate Reconciliation, Percent, Total	1.90%	7.40%
Evergy Metro
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current Federal Tax Expense (Benefit)	$ 2.0	$ (5.1)
Current State and Local Tax Expense (Benefit)	3.3	1.6
Current Income Tax Expense (Benefit), Total	5.3	(3.5)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred Federal Income Tax Expense (Benefit)	4.8	12.4
Deferred State and Local Income Tax Expense (Benefit)	(2.9)	(1.2)
Deferred Income Tax Expense (Benefit), Total	1.9	11.2
Investment Tax Credits
Investment tax credit amortization	(0.8)	(0.8)
Income Tax Expense (Benefit), Total	$ 6.4	$ 6.9
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%
Effect Of [Abstract]
COLI policies	(0.10%)	(0.10%)
State income taxes	0.90%	0.60%
Flow through depreciation for plant-related differences	(7.70%)	(8.10%)
Federal tax credits	(0.60%)	(0.20%)
AFUDC equity	0.00%	(0.90%)
Amortization of federal investment tax credits	(0.90%)	(0.90%)
Stock compensation	1.90%	1.00%
Officer compensation limitation	1.90%	0.60%
Other	0.00%	(0.10%)
Effective Income Tax Rate Reconciliation, Percent, Total	16.40%	12.90%