Leases - Schedule of Information on Leases (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Lease cost	$ 83.7	$ 76.0	$ 72.2
Cash paid for leases recognized in operating cash flows	81.4	73.6
Right-of-use assets obtained in exchange for new lease liabilities	83.5	55.0
Right-of-use assets recognized in Other assets	$ 274.5	$ 266.7
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssets	us-gaap:OtherAssets
Lease liabilities recognized in Other current liabilities	$ 75.0	$ 64.2
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Lease liabilities recognized in Other long-term liabilities	$ 217.8	$ 215.5
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent
Weighted-average remaining lease term	5 years 9 months 18 days	6 years 3 months 18 days
Weighted-average discount rate	2.30%	2.70%