Draws on Credit Facility that are Designated as Net Investments in International Operations (Parenthetical) (Detail) In Millions, unless otherwise specified	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2014 Canadian Dollars USD ($)		Dec. 31, 2014 Canadian Dollars CAD		Dec. 31, 2014 Canadian Dollars Not Designated as Hedging Instrument USD ($)
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Credit facility	$ 704	$ 946	$ 27	[1]	31	[1]	$ 65

[1] We have drawn an additional $65 million on the credit facility in Canadian dollars that has not been designated as a hedging instrument.