Risk Management (Risk Management Activities) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Derivative Instruments, Gain (Loss) [Line Items]
Product revenues	$ 49.1	$ 84.7	$ 236.0	$ 395.7
Commodity contract
Derivative Instruments, Gain (Loss) [Line Items]
Product costs, net	$ 18.0	$ (45.0)	$ (13.5)	$ 6.3