SUPPLEMENTAL CASH FLOW INFORMATION - SUPPLEMENTAL INFORMATION (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018
Supplemental cash flow information
Cash (paid) for interest, net of amount capitalized	$ (247.9)	$ (215.6)
Cash (paid) for income taxes, net	(15.1)	(47.6)
Significant non-cash investing and financing transactions
Accounts payable related to construction costs	137.3	77.4
Non-cash capital contributions from noncontrolling interest	$ 10.2	$ 0.0

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

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