Changes in Components of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Beginning Balance	$ (172.2)	$ (364.9)
Reclassification adjustment from AOCI, Pension and Other Postretirement Benefit Plans - Net of Tax	1.0	1.5
Pension and other retirement benefit - Net of Tax	1.0	1.5
Net unrealized gain (losses) on cash flow - Net of Tax	1.5	(0.2)
Reclassification gain (losses) on cash flow - Net of Tax	(0.1)	(0.9)
Gains/(Losses) on cash flow hedges - Net of Tax	1.4	(1.1)
Foreign currency translation adjustments before reclassification - Net of Tax	125.2	12.1
Available for sale securities before reclassification - Net of Tax		0.5
Amounts reclassified from AOCI	0.9	0.6
Total other comprehensive income (loss) - Net of Tax	127.6	13.0
Ending Balance	(51.9)	(357.3)
Parent [Member]
Foreign currency translation adjustments before reclassification - Net of Tax	120.2	6.9
Foreign currency translation adjustments - Net of Tax	120.2	6.9
Available for sale securities before reclassification - Net of Tax		0.3
Gains on Available for sale securities - Net of Tax		0.3
Other comprehensive income/(loss) before reclassifications	121.7	7.0
Total other comprehensive income (loss) - Net of Tax	120.3	7.6
Financial Instruments - Overall (ASU 2016-01) [Member]
Amount reclassified from AOCI, Available fo Sale Securities - Net of Tax	(2.3)
Gains on Available for sale securities - Net of Tax	(2.3)
Gains Losses on Cash Flow Hedges [Member]
Beginning Balance	0.9	1.7
Ending Balance	2.3	0.6
Pension and Other Retirement Benefits [Member]
Beginning Balance	(61.5)	(79.5)
Ending Balance	(60.5)	(78.0)
Foreign Currency Translation Adjustments [Member]
Beginning Balance	(113.9)	(290.2)
Ending Balance	6.3	(283.3)
Gains on Available for Sale Securities [Member]
Beginning Balance	$ 2.3	3.1
Ending Balance		$ 3.4