Selected Quarterly Financial Data (Unaudited) - Narrative (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Indemnification settlement amount	$ 20.0
Remaining settlement amount received, attributable to remediation costs	16.0			$ 16.0
Remaining settlement amount received, attributable to concessions made under Settlement Agreement	$ 4.0			4.0
Gain on remeasurement of equity method investment			$ (190.1)	0.0	$ 190.1	$ 0.0
Impact of Tax Cuts and Jobs Act		$ 166.9		$ (0.6)	$ (166.9)	$ 0.0
Alon USA Energy, Inc.
Schedule of Equity Method Investments [Line Items]
Tax effect of write off of deferred tax assets			$ 46.9