Summary of Significant Accounting Policies - Schedule of Change in Conditional AROs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year	$ 51.4	$ 51.4	$ 46.0
(Reductions)/ additions and other, net	(2.3)	(2.7)	2.6
Accretion	2.7	2.7	2.8
Balance at end of year	$ 51.8	$ 51.4	$ 51.4