Components of Other Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2010		Sep. 30, 2010		Jun. 30, 2010		Mar. 31, 2010		Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net income	$ 177	[1]	$ 63	[1]	$ 191	[1]	$ 201	[1]	$ 416	[1]	$ 231	[1]	$ 207	[1]	$ 299	[1]	$ 631	$ 1,152	$ 902
Unrealized gains (losses), net of tax of $1, $(2), and $(2)																	(1)	5	7
Reclassification adjustment for losses (gains) included in net income, net of tax effect of $1, $0, and $1																	(2)	(2)	(3)
Net unrealized gains (losses) on available for sale securities																	(3)	3	4
Foreign currency translation adjustment, net of tax effect of $20, $29, and $0																	(123)	(137)	62
Other																	0		1
Other comprehensive income (loss)																	(126)	(134)	67
Comprehensive income																	$ 505	$ 1,018	$ 969

[1] The sum of quarterly amounts, including per share amounts, may not equal amounts reported for year-to-date periods. This is due to the effects of rounding and changes in the number of weighted-average shares outstanding for each period.