Income Taxes (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Changes in the amount of unrecognized tax benefits
Beginning balance	$ 249	$ 437	$ 718
Additions based on tax positions related to the current year	26	32	43
Additions for tax positions of prior years	40	62	74
Reductions for tax positions of prior years	(21)	(163)	(16)
Settlements	(27)	(125)	(377)
Foreign currency translation	1	6	(5)
Ending balance	$ 268	$ 249	$ 437