Financial Instruments (Realized Gains and Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Proceeds from sales	$ 145.6	$ 132.9	$ 174.7
Realized gross gains on sales	0.7	0.4	2.8
Realized gross losses on sales	$ 4.0	$ 9.7	$ 1.7