RECEIVABLES (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	$ 176.1	$ 127.8
Allowance for credit losses	(18.0)	(10.5)
Total	396.0	228.5
Evergy Kansas Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	182.8	94.5
Allowance for credit losses	(4.9)	(3.8)
Total	265.6	140.4
Evergy Metro
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	14.1	23.1
Allowance for credit losses	(9.0)	(4.6)
Total	101.5	48.1
Customer accounts receivable | Billed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	12.9	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	5.2	3.1
Customer accounts receivable | Unbilled
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	225.0	104.0
Customer accounts receivable | Unbilled | Evergy Kansas Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	87.7	49.7
Customer accounts receivable | Unbilled | Evergy Metro
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	$ 91.2	$ 26.5