Derivatives and Hedging (Details 2) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Derivatives, Fair Value
Notional Amount	$ 1,595		$ 1,849
Derivative Assets	65		210
Derivative Liabilities	113		251
Gross Amounts Offset in the Statement of Financial Position	(26)		(160)
Net Amounts of Assets Presented in the Statement of Financial Position	39	[1]	50	[1]
Gross Amounts Offset in the Statement of Financial Position	(26)		(160)
Net Amounts of Liabilities Presented in the Statement of Financial Position	87	[2]	91	[2]
Derivatives accounted for as hedges [Member]
Derivatives, Fair Value
Notional Amount	1,328		1,544
Derivative Assets	64		208
Derivative Liabilities	112		250
Gross Amounts Offset in the Statement of Financial Position	(25)		(160)
Net Amounts of Assets Presented in the Statement of Financial Position	39	[1]	48	[1]
Gross Amounts Offset in the Statement of Financial Position	(25)		(160)
Net Amounts of Liabilities Presented in the Statement of Financial Position	87	[2]	90	[2]
Interest rate contracts [Member] | Derivatives accounted for as hedges [Member]
Derivatives, Fair Value
Notional Amount	169		336
Derivative Assets	8		17
Derivative Liabilities	0		0
Gross Amounts Offset in the Statement of Financial Position	0		0
Net Amounts of Assets Presented in the Statement of Financial Position	8	[1]	17	[1]
Gross Amounts Offset in the Statement of Financial Position	0		0
Net Amounts of Liabilities Presented in the Statement of Financial Position	0	[2]	0	[2]
Foreign exchange contracts [Member] | Derivatives accounted for as hedges [Member]
Derivatives, Fair Value
Notional Amount	1,159		1,208
Derivative Assets	56		191
Derivative Liabilities	112		250
Gross Amounts Offset in the Statement of Financial Position	(25)		(160)
Net Amounts of Assets Presented in the Statement of Financial Position	31	[1]	31	[1]
Gross Amounts Offset in the Statement of Financial Position	(25)		(160)
Net Amounts of Liabilities Presented in the Statement of Financial Position	87	[2]	90	[2]
Foreign exchange contracts [Member] | Derivatives not accounted for as hedges [Member]
Derivatives, Fair Value
Notional Amount	267		305
Derivative Assets	1		2
Derivative Liabilities	1		1
Gross Amounts Offset in the Statement of Financial Position	(1)		0
Net Amounts of Assets Presented in the Statement of Financial Position	0	[1]	2	[1]
Gross Amounts Offset in the Statement of Financial Position	(1)		0
Net Amounts of Liabilities Presented in the Statement of Financial Position	$ 0	[2]	$ 1	[2]

[1] Included within Other current assets or Other non-current assets

[2] Included within Other current liabilities or Other non-current liabilities