SUPPLEMENTAL CASH FLOW INFORMATION - SUPPLEMENTAL INFORMATION (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021
Supplemental cash flow information
Cash paid for interest, net of amount capitalized	$ 311.4	$ 310.9
Cash paid for income taxes, net	52.3	33.8
Significant non-cash investing and financing transactions:
Accounts payable related to construction costs	170.9	144.0
Accounts payable related to Thunderhead acquisition milestone payments	19.0	0.0
Increase in receivable related to insurance proceeds	0.0	58.3
Liabilities accrued for software licensing agreement	$ 7.4	$ 0.0

Future cash outflow to pay for purchases of fixed assets that have occurred.

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Future cash outflow to pay for construction in progress expenditures that have occurred.

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Future cash outflow to pay for a software licensing agreement

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