Fair Value Measurements Fair Value Measurements (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019		Sep. 30, 2020	Sep. 30, 2019		Dec. 31, 2019
Fair Value Disclosures [Abstract]
Asset Impairment Charges	$ 31.3	$ 126.3		$ 3,253.0	$ 127.5
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Asset Impairment Charges	31.3	126.3		3,253.0	127.5
Redeemable Noncontrolling Interest	42.1			42.1			$ 41.1
Property, Plant and Equipment
Fair Value Disclosures [Abstract]
Asset Impairment Charges				169.6	127.5
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Asset Impairment Charges				169.6	127.5
Property, Plant and Equipment | Fair Value, Nonrecurring
Fair Value Disclosures [Abstract]
Property, Plant, and Equipment, Fair Value	353.3	104.0	[1]	353.3	104.0	[1]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Property, Plant, and Equipment, Fair Value	$ 353.3	$ 104.0	[1]	$ 353.3	$ 104.0	[1]
Property, Plant and Equipment | Fair Value, Nonrecurring | Measurement Input, Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value unobservable input rate	10.80%	10.80%		10.80%	10.80%

[1] Includes $104.0 million fair value of vessels determined using the transaction price of a similar vessel, resulting in a Level 2 fair value measurement.