Accumulated Other Comprehensive Income - Changes in Components of Accumulated Other Comprehensive Income, Net of Tax (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($)
Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income, Beginning Balance	$ (434.0)
Accumulated Other Comprehensive Income, Ending Balance	(423.8)
Foreign Currency Translation [Member]
Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income, Beginning Balance	(323.4)
AOCI before reclassifications	49.0
Accumulated Other Comprehensive Income, Ending Balance	(274.4)
Unrealized (Losses) Gains on Securities [Member]
Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income, Beginning Balance	(0.1)
Accumulated Other Comprehensive Income, Ending Balance	(0.1)
Defined Benefit Plan Items [Member]
Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income, Beginning Balance	(142.8)
AOCI before reclassifications	(5.3)
Reclassifications	1.8
Accumulated Other Comprehensive Income, Ending Balance	(146.3)
Cash Flow Hedges [Member]
Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income, Beginning Balance	32.3
AOCI before reclassifications	(26.3)
Reclassifications	(9.0)
Accumulated Other Comprehensive Income, Ending Balance	$ (3.0)