Fair Value Measurements - Level 3 Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Level 3 rollforward
Balance at the beginning of the period	$ 7.2	$ 7.8	$ 2.4
Purchases	28.7	21.0	23.7
Net realized and unrealized gains (losses) included in earnings	(0.7)	(0.5)	0.5
Settlements	(27.4)	(21.1)	(18.8)
Balance at the end of period	7.8	7.2	7.8
Net unrealized gains (losses) included in earnings attributable to level 3 derivatives held at the end of the reporting period	$ 0.0	$ 0.5	$ (0.4)