Derivatives and Hedging Offsetting of financial assets and derivatives assets (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Derivative [Line Items]
Gross Amounts of Recognized Assets	$ 80		$ 210
Gross Amounts Offset in the Statement of Financial Position	(30)		(160)
Net Amounts of Assets Presented in the Statement of Financial Position	50	[1]	50	[1]
Other Current Assets [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	46		167
Net Amounts of Assets Presented in the Statement of Financial Position	18		18
Other Noncurrent Assets [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	34		43
Net Amounts of Assets Presented in the Statement of Financial Position	32		32
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	80	[2]	208	[2]
Gross Amounts Offset in the Statement of Financial Position	(30)		(160)
Net Amounts of Assets Presented in the Statement of Financial Position	50	[1]	48	[1]
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	9	[2]	17	[2]
Gross Amounts Offset in the Statement of Financial Position	0		0
Net Amounts of Assets Presented in the Statement of Financial Position	9	[1]	17	[1]
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	71	[2]	191	[2]
Gross Amounts Offset in the Statement of Financial Position	(30)		(160)
Net Amounts of Assets Presented in the Statement of Financial Position	41	[1]	31	[1]
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	80	[2]	210	[2]
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	0	[2]	2	[2]
Gross Amounts Offset in the Statement of Financial Position	0		0
Net Amounts of Assets Presented in the Statement of Financial Position	$ 0	[1]	$ 2	[1]

[1] Included within Other current assets ($18 million in both 2013 and 2012) or Other non-current assets ($32 million in both 2013 and 2012)

[2] Included within Other current assets ($46 million in 2013 and $167 million in 2012) or Other non-current assets ($34 million in 2013 and $43 million in 2012)