Components of Interest and Other Income, net (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Component of Other Income, Nonoperating [Line Items]
Interest income	$ 182	$ 190
Interest expense	(20)	(4)
Realized gains on available-for-sale investments, net	120	27
Foreign currency exchange losses, net	(143)	(128)
Other	17	11
Interest and other income, net	$ 156	$ 96