Investment in Unconsolidated Affiliates Summarized Income Statement of Equity Method Investment (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Schedule of Equity Method Investments [Line Items]
Operating revenues	$ 577.4		$ 503.5		$ 2,208.0	$ 934.8
Operating Income (Loss)	129.5		125.4		178.1	181.7
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	112.9	$ 52.7	85.9	$ (491.8)	165.6	(405.9)
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Schedule of Equity Method Investments [Line Items]
Operating revenues	787.0		515.0		1,757.0	1,163.0
Cost of Revenue	426.0		177.0		945.0	403.0
Operating Income (Loss)	124.0		80.0		330.0	226.0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 79.0		$ 35.0		$ 234.0	$ 138.0