Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Property, plant and equipment, and intangibles	$ (275.6)	$ (180.9)
Partnership and equity investments	22.2
Partnership and equity investments		(83.7)
Deferred revenues	(5.5)	(6.5)
Derivatives and hedging	(12.5)
Derivatives and hedging		4.8
Compensation and employee benefits	15.5	15.9
Net operating loss carryforwards	39.9	26.5
Reserves and accruals	63.0	40.8
Inventories	1.3	4.4
Valuation allowance	(58.5)	(21.2)
Total net deferred tax liabilities	$ (210.2)	$ (199.9)