Gains and Losses on Derivatives Designated as Hedging Instruments (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net Investment Hedging [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain/(loss) recognized in AOCI on derivative (effective portion)	$ 18.1	$ 19.4	$ 3.7
Net Investment Hedging [Member] | Foreign Exchange Forwards [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain/(loss) recognized in AOCI on derivative (effective portion)	13.4	$ 19.4	$ 3.7
Net Investment Hedging [Member] | Long-Term Debt [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain/(loss) recognized in AOCI on derivative (effective portion)	4.7
Cash Flow Hedging [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain/(loss) recognized in AOCI on derivative (effective portion)	(1.1)
Cash Flow Hedging [Member] | Treasury Rate Lock [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain/(loss) recognized in AOCI on derivative (effective portion)	$ (1.1)