Unaudited Condensed Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Statement of Other Comprehensive Income [Abstract]
Net income	$ 220	$ 270	$ 468	$ 673
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of $0 tax in 2012 and 2011	10	(62)	(15)	(42)
Unrealized gains (losses) on marketable securities, net of $0 tax in 2012 and 2011	2	(4)	4	1
Other comprehensive income (loss)	12	(66)	(11)	(41)
Comprehensive income	$ 232	$ 204	$ 457	$ 632