Balance Sheet Accounts - Schedule of Other Current Assets (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Deferred costs recoverable from the U.S. government	$ 39.4	$ 37.4
Income tax receivable	0.0	13.8
Inventories	13.3	10.0
Prepaid expenses	17.6	15.3
Other	47.4	23.0
Other current assets	$ 117.7	$ 99.5