LEASES - Narrative (Details)	12 Months Ended
	Dec. 31, 2019
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	1 year
Minimum | Evergy Kansas Central
Lessee, Lease, Description [Line Items]
Remaining lease term	1 year
Minimum | Evergy Metro
Lessee, Lease, Description [Line Items]
Remaining lease term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	19 years
Maximum | Evergy Kansas Central
Lessee, Lease, Description [Line Items]
Remaining lease term	19 years
Maximum | Evergy Metro
Lessee, Lease, Description [Line Items]
Remaining lease term	26 years