Net Investment Hedge Gains and Losses Recognized in AOCI (Detail) - Net Investment Hedges - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative [Line Items]
Hedging Instrument Gain/(Loss) Recognized in AOCI (Before Tax)	$ (81.1)	$ (29.6)	$ 35.5	$ (40.2)
Foreign Exchange Contracts
Derivative [Line Items]
Hedging Instrument Gain/(Loss) Recognized in AOCI (Before Tax)	$ (81.1)	(22.9)	30.5	(31.9)
Sterling Denominated Subordinated Debt
Derivative [Line Items]
Hedging Instrument Gain/(Loss) Recognized in AOCI (Before Tax)		$ (6.7)	$ 5.0	$ (8.3)