RECEIVABLES (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	$ 133.2	$ 127.8
Allowance for credit losses	(11.5)	(10.5)
Total	189.2	228.5
Evergy Kansas Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	120.4	94.5
Allowance for credit losses	(4.1)	(3.8)
Total	142.4	140.4
Evergy Metro
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	18.4	23.1
Allowance for credit losses	(5.2)	(4.6)
Total	33.4	48.1
Customer accounts receivable | Billed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	3.9	7.2
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	3.3	3.1
Customer accounts receivable | Unbilled
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	63.6	104.0
Customer accounts receivable | Unbilled | Evergy Kansas Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	26.1	49.7
Customer accounts receivable | Unbilled | Evergy Metro
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	$ 16.9	$ 26.5