Supplemental Cash Flow Information - Schedule Of Noncash Investing and Financing Activities (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 115.1
Accrued liabilities for purchases of property, plant and equipment	28.7	$ 21.4
Right-of-use assets obtained in exchange for new operating lease liabilities	6.0	12.7
Accrued proceeds from company-owned life insurance benefits		$ 0.8
Remeasurement of operating lease right-of-use assets	$ (6.2)