PENSION PLANS AND POST-RETIREMENT BENEFITS - Narrative (Details) $ in Millions	6 Months Ended
	Jun. 30, 2026 USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	$ 46.8
Contributions to plans remainder of year	34.8
Post-Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	0.3
Contributions to plans remainder of year	0.2
Evergy Kansas Central \| Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	32.0
Contributions to plans remainder of year	18.4
Evergy Kansas Central \| Post-Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	0.1
Contributions to plans remainder of year	0.1
Evergy Metro \| Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	14.8
Contributions to plans remainder of year	16.4
Evergy Metro \| Post-Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	0.2
Contributions to plans remainder of year	$ 0.1