Commitments and Contingencies - Asset Retirement Obligations (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		$ 72.1	$ 5.2
Liabilities identified	[1]	(1.2)	66.2
Liabilities settled		(2.2)	0.0
Accretion expense		1.9	0.7
Reclassification from discontinued operations		4.9	0.0
Ending balance		$ 75.5	$ 72.1

[1] All asset retirement obligations were assumed in the Delek/Alon Merger.