ORGANIZATION AND BASIS OF PRESENTATION - Organization (Details) customer in Millions	9 Months Ended
	Sep. 30, 2020 customer kilovolt_line subsidiary segment mi MW
Summary Of Accounting Policies [Line Items]
Owned generating capacity and renewable purchased power | MW	14,700
Number of customers served | customer	1.6
Number of segments | segment	1
Prairie Wind Transmission, LLC
Summary Of Accounting Policies [Line Items]
Transmission line length | mi	108
Transmission line electrical potential | kilovolt_line	345
Evergy Kansas Central
Summary Of Accounting Policies [Line Items]
Number of active wholly owned subsidiaries | subsidiary	1
Transource Energy, LLC | Evergy Transmission Company LLC
Summary Of Accounting Policies [Line Items]
Ownership percentage	13.50%
Transource Energy, LLC | AEP Transmission Holding Company, LLC
Summary Of Accounting Policies [Line Items]
Ownership interest	86.50%
Prairie Wind Transmission, LLC | Evergy Kansas Central
Summary Of Accounting Policies [Line Items]
Ownership percentage	50.00%