Commitments and Contingencies - Components of Lease Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Lease Cost [Abstract]
Operating lease cost	$ 84.8	$ 89.3
Variable lease cost	31.9	32.7
Sublease income	(1.6)	(1.7)
Total lease cost	$ 115.1	$ 120.3