Other Non-Operating Interest (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Component of Other Expense Income Nonoperating [Line Items]
FX gain/(loss)	$ (6.7)	$ 4.3	$ (12.5)	$ 9.1
Legacy Tax benefit		1.6		1.6
Joint venture income	2.7	2.3	7.7	7.2
Other	2.6	(1.3)	2.3	(2.4)
Total	$ (1.4)	$ 6.9	$ (2.5)	$ 15.5