Derivative Instruments - Derivatives Gains and Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	$ 56.3	$ 77.9
Not Designated as Hedging Instrument | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on economic hedges	11.2	52.0
Not Designated as Hedging Instrument | Commodity contracts | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on commodity derivatives not designated as hedging instruments	57.2	77.2
Not Designated as Hedging Instrument | Commodity contracts | Other Operating Income (Expense)
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on commodity derivatives not designated as hedging instruments	(1.1)	0.0
Designated as Hedging Instrument | Commodity contracts | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Realized gains reclassified out of accumulated other comprehensive income and into cost of materials and other on commodity derivatives designated as cash flow hedging instruments	$ 0.2	$ 0.7