GENERAL AND SIGNIFICANT ACCOUNTING POLICIES - CAPITAL CONSTRUCTION FUND (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Accounts receivable, net	$ 328.5		$ 328.5		$ 343.7
Cash Deposits Into CCF			579.7	$ 31.2
Withdrawals from CCF			14.7	31.2
Capital construction fund	565.0		565.0
Eligible Accounts Receivable Assigned to CCF
Accounts receivable, net	9.8		9.8		$ 9.8
Cash Deposits Into CCF	569.0	$ 0.0	579.7	31.2
Withdrawals from CCF	$ 4.0	$ 0.0	$ 14.7	$ 31.2