Supplemental Cash Flow Information (Details) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019
Cash:
Interest paid, net of capitalized interest	[1]	$ 165.3	$ 106.2
Income taxes paid, net of refunds		0.1	(1.7)
Non-cash investing activities:
Impact of capital expenditure accruals on property, plant and equipment, net		(143.9)	(4.3)
Transfers from materials and supplies inventory to property, plant and equipment		1.8	16.4
Non-cash financing activities:
Changes in accrued distributions to noncontrolling interests		$ (1.9)	$ 49.6

[1] Interest capitalized on major projects was $22.5 million and $36.1 million for the six months ended June 30, 2020 and 2019.