RECEIVABLES (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	$ 181.2	$ 127.8
Allowance for credit losses	(15.2)	(10.5)
Total	318.5	228.5
Evergy Kansas Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	206.7	94.5
Allowance for credit losses	(5.5)	(3.8)
Total	256.5	140.4
Evergy Metro
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	24.7	23.1
Allowance for credit losses	(6.5)	(4.6)
Total	80.0	48.1
Customer accounts receivable | Billed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	8.6	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	4.9	3.1
Customer accounts receivable | Unbilled
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	143.9	104.0
Customer accounts receivable | Unbilled | Evergy Kansas Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	55.3	49.7
Customer accounts receivable | Unbilled | Evergy Metro
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer accounts receivable	$ 56.9	$ 26.5