Supplemental Cash Flow Information - Supplemental Disclosures of Cash Flow Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest, net of amount capitalized	$ 113.8	$ 127.9	$ 137.2
Cash paid for income taxes	114.9	101.7	$ 28.9
Operating cash flows used for operating leases	77.7	76.1
Operating cash flows used for finance leases	0.6	0.5
Financing cash flows used for finance leases	$ 3.5	$ 11.0