Summary of Notional Amounts of Outstanding Foreign Exchange Forwards, Net Investment Hedging (Detail) - Net Investment Hedging [Member] € in Millions, ¥ in Millions, £ in Millions	Mar. 31, 2016 EUR (€)	Mar. 31, 2016 GBP (£)	Mar. 31, 2016 JPY (¥)	Dec. 31, 2015 EUR (€)	Dec. 31, 2015 GBP (£)	Dec. 31, 2015 JPY (¥)
Contracts to Sell GBP for Euros [Member]
Derivative [Line Items]
Derivative Notional Amount | £		£ 21.5			£ 21.2
Contracts to Sell Japanese Yen for USD [Member]
Derivative [Line Items]
Derivative Notional Amount | ¥			¥ 19,400.0			¥ 19,400.0
Long Term Debt [Member]
Derivative [Line Items]
Derivative Notional Amount | €	€ 400.0			€ 400.0