Other Current Assets (Detail) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses	$ 167.7	$ 136.2
Contract assets (Note 12)	6.1	5.2
Marketable securities (Note 4)	3.1	3.1
Other Assets, Miscellaneous, Current	131.7	87.1
Total other current assets	$ 308.6	$ 231.6