Derivative Instruments - Gains (Losses) on Trading Derivatives (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Forward Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Realized gains (losses)	$ 1.2	$ 2.8	$ 19.7	$ 4.9
Unrealized gains (losses)	0.0	(0.8)	(0.3)	(0.4)
Total	1.2	2.0	19.4	4.5
Commodity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Realized gains (losses)	(0.3)	(0.9)	11.6	(5.9)
Unrealized gains (losses)	0.7	0.7	(15.8)	0.2
Total	$ 0.4	$ (0.2)	$ (4.2)	$ (5.7)