Effect of Derivative Instruments on Income and Accumulated Other Comprehensive Income (Parenthetical) (Detail) (Derivatives in Fair Value Hedging Relationship, Interest and other income, net, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Derivatives in Fair Value Hedging Relationship | Interest and other income, net
Derivative Instruments, Gain (Loss) [Line Items]
Losses related to the amount excluded from effectiveness testing of the hedges	$ 8	$ 14	$ 6