Commitments and Contingencies - Rollforward of Environmental Liability and Related Assets (Detail) - Environmental Related Matters [Member] - Liability [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Environmental Liability and Related Assets [Roll Forward]
Balance as of January 1	$ 66.8	$ 73.9
Changes in estimates for pre-existing accruals	0.5	6.6
Accruals added during the period for new matters	0.0	2.0
Net cash activity(a)	(5.4)	(15.8)	[1]
Foreign currency	0.0	0.1
Balance as of December 31	$ 61.9	$ 66.8

[1] (a) Includes cash payments for the year ended December 31, 2018 of $10.2, related to the sale of a former operating location.