Summary of Other Income (Expense), Net (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2012	Mar. 31, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Component of Other Income, Nonoperating [Line Items]
Interest income	$ 6		$ 7	$ 17	$ 20
Foreign exchange gain (loss)	(2)		12	(12)	10
Loss on extinguishment of debt					(53)
Gain on sale of equity investments			60		60
Strategic transaction expenses	(4)		(1)	(8)	(3)
Impairment of long-lived assets		(2)	(5)	(2)	(5)
Other	2		6	14	22
Other income, net	$ 2		$ 79	$ 9	$ 51