Crude Oil Supply and Inventory Purchase Agreement - Interest Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Oil and Gas, Delivery Commitment [Line Items]
Gain (Loss) On Financing Interest Expense	$ (3.9)	$ 5.1
Interest expense | J. Aron
Oil and Gas, Delivery Commitment [Line Items]
Interest Income (Expense), Net	9.1	6.0
El Dorado Refinery | Interest expense | J. Aron
Oil and Gas, Delivery Commitment [Line Items]
Interest Income (Expense), Net	3.6	3.1
Krotz Spring Refinery | Interest expense | J. Aron
Oil and Gas, Delivery Commitment [Line Items]
Interest Income (Expense), Net	1.4	3.0
Big Spring refinery | Interest expense | J. Aron
Oil and Gas, Delivery Commitment [Line Items]
Interest Income (Expense), Net	$ 4.1	$ (0.1)