RECEIVABLES (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	$ 127.8	$ 95.0
Allowance for doubtful accounts	(10.5)	(9.2)
Total	228.5	193.7
Evergy Kansas Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	94.5	71.6
Allowance for doubtful accounts	(3.8)	(3.9)
Total	140.4	84.3
Evergy Metro
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	23.1	15.8
Allowance for doubtful accounts	(4.6)	(3.8)
Total	48.1	62.7
Customer accounts receivable | Billed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	7.2	16.7
Customer accounts receivable | Billed | Evergy Kansas Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	0.0	0.0
Customer accounts receivable | Billed | Evergy Metro
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	3.1	7.8
Customer accounts receivable | Unbilled
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	104.0	91.2
Customer accounts receivable | Unbilled | Evergy Kansas Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	49.7	16.6
Customer accounts receivable | Unbilled | Evergy Metro
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	$ 26.5	$ 42.9