Lease Commitments - Lease Cost Components (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating Lease Cost	$ 119.4	$ 102.2
Variable Lease Cost	32.7	38.7
Sublease Income	(4.8)	(6.6)
Total Lease Cost	$ 147.3	$ 134.3