Fair Value Measurements - Changes in Fair Value of Level 3 (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Summary of net changes in fair value of the company's level 3 financial assets and liabilities
Realized loss on derivative instruments	$ 15.2	$ (54.3)	$ 9.6	$ (14.5)
Unrealized gain (loss) on derivative instruments	13.6	(36.3)	52.3	18.8
Level 3
Summary of net changes in fair value of the company's level 3 financial assets and liabilities
Fair value at January 1,			(40.8)	(73.8)
Realized loss on derivative instruments			(42.7)	(33.3)
Unrealized gain (loss) on derivative instruments			52.3	18.8
Settlements			42.7	33.3
Fair value at June 30,	$ 11.5	$ (55.0)	$ 11.5	$ (55.0)