Inventory - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Inventory [Line Items]
Inventory valuation reserves	$ 1.1		$ 1.1		$ 31.1
Inventory adjustments	21.5		21.5
Cost of sales
Inventory [Line Items]
Inventory valuation gains (losses)	(0.2)	$ 9.5	29.9	$ (65.6)
Operating Expense
Inventory [Line Items]
Inventory adjustments	14.0		14.0
Depreciation Expense | Refining
Inventory [Line Items]
Inventory adjustments	7.5		7.5
LIFO inventory
Inventory [Line Items]
Inventory valuation reserves	$ 0.0		$ 0.0		$ 30.3