Accumulated Other Comprehensive Income Changes in Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended							3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Foreign Currency Translation Adjustments	Mar. 31, 2012 Foreign Currency Translation Adjustments	Mar. 31, 2013 Employee Benefit Plan Adjustments	Mar. 31, 2012 Employee Benefit Plan Adjustments	Dec. 31, 2011 Employee Benefit Plan Adjustments	Mar. 31, 2013 Changes in Fair Value of Effective Cash Flow Hedges	Mar. 31, 2012 Changes in Fair Value of Effective Cash Flow Hedges	Mar. 31, 2013 Changes in Fair Value of Available for Sale Securities	Mar. 31, 2012 Changes in Fair Value of Available for Sale Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	$ (197)	$ (179)	$ (166)	$ (162)	$ (22)	$ (18)	$ (18)	$ (10)	$ 0	$ 1	$ 1
Other comprehensive income (loss) before reclassifications	16	(3)	(21)	1	31			3	(5)	3	1
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(11)				(11)
Net current period other comprehensive income	5	(3)	(21)	1	20			3	(5)	3	1
Accumulated other comprehensive income (loss), ending balance	$ (192)	$ (182)	$ (187)	$ (161)	$ (2)	$ (18)	$ (18)	$ (7)	$ (5)	$ 4	$ 2