Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Components Of Accumulated Other Comprehensive Income Loss Line Items
Currency translation adjustment	$ (109)	[1]	$ (109)	[1]	$ (109)	[1]
Unrealized gain (loss) on derivatives (Note 3)	(6)		114		(19)
Unfunded pension and postretirement benefit plan	(16)		(14)		(13)
Accumulated other comprehensive loss	$ (131)		$ (9)		$ (141)

[1] Currency translation adjustments resulting from translating the Canadian subsidiaries' financial statements into U.S. dollar equivalents, prior to adoption of the U.S. dollar as their functional currency, were reported separately and accumulated in other comprehensive income (loss).