COMMITMENTS AND CONTINGENCIES - Narrative (Details) $ in Millions	Dec. 31, 2020 USD ($)
Estimates Of Environmental Financial Impact And Related Issues [Line Items]
Industry aggregate limit for nuclear insurance	$ 3,200.0
Industry aggregate limit for non nuclear insurance	1,800.0
Nuclear liability insurance, full limit of public liability	13,800.0
Nuclear liability insurance, maximum available commercial insurance	500.0
Nuclear liability insurance, industry wide retrospective assessment program	13,300.0
Nuclear liability insurance, owners insurance amount, maximum	137.6
Nuclear liability insurance, owners insurance, amount per incident	20.5
Nuclear liability insurance, owners property insurance, maximum	2,800.0
Nuclear liability insurance, owners nonnuclear property insurance, maximum	2,300.0
Nuclear liability insurance, owners property insurance assessment, maximum	33.2
Evergy
Estimates Of Environmental Financial Impact And Related Issues [Line Items]
Nuclear liability insurance, owners insurance amount, maximum	129.4
Nuclear liability insurance, owners insurance, amount per incident	19.2
Nuclear liability insurance, owners property insurance assessment, maximum	31.2
Evergy Kansas Central
Estimates Of Environmental Financial Impact And Related Issues [Line Items]
Nuclear liability insurance, owners insurance amount, maximum	64.7
Nuclear liability insurance, owners insurance, amount per incident	9.6
Nuclear liability insurance, owners property insurance assessment, maximum	15.6
Evergy Metro
Estimates Of Environmental Financial Impact And Related Issues [Line Items]
Nuclear liability insurance, owners insurance amount, maximum	64.7
Nuclear liability insurance, owners insurance, amount per incident	9.6
Nuclear liability insurance, owners property insurance assessment, maximum	$ 15.6