Commitments and Contingencies - Changes in Accrued Environmental Remediation and Related Costs (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Environmental Remediation Obligations [Abstract]
Balance at the beginning of the year	$ 122.6
Additions charged to expense, net	3.1
Payments, net	(0.9)
Currency and other	0.1
Balance at the end of period	124.9
Amounts recognized in our Condensed Consolidated Balance Sheet at the end of the period:
Current liabilities		$ 14.7	$ 15.3
Noncurrent liabilities		110.2	107.3
Total	$ 122.6	$ 124.9	$ 122.6