SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Supplemental Cash Flow Information [Abstract]
Cash paid for interest, net of amount capitalized	$ 234.0	$ 233.8
Cash paid for income taxes, net	40.3	0.0
Significant non-cash investing and financing transactions:
Accounts payable related to construction costs	50.0	27.8
Receivable related to insurance proceeds for property damage (1)	$ 39.6	$ 1.5