Derivative Instruments and Hedging Activities (Assets and LIabilities - Designated vs. Not Designated Hedging Instruments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Total asset derivatives	$ 280	$ 240
Total liability derivatives	514	371
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	31	113
Total liability derivatives	490	351
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	249	127
Total liability derivatives	24	20
Interest Rate Contract
Derivatives, Fair Value [Line Items]
Total asset derivatives	0	98
Total liability derivatives	416	322
Interest Rate Contract | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	0	96
Total liability derivatives	416	318
Interest Rate Contract | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	0	2
Total liability derivatives	0	4
Cross Currency Interest Rate Contract
Derivatives, Fair Value [Line Items]
Total asset derivatives	0	5
Total liability derivatives	29	11
Cross Currency Interest Rate Contract | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	0	5
Total liability derivatives	29	11
Cross Currency Interest Rate Contract | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	0	0
Total liability derivatives	0	0
Foreign Exchange Contract
Derivatives, Fair Value [Line Items]
Total asset derivatives	236	113
Total liability derivatives	52	21
Foreign Exchange Contract | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	6	4
Total liability derivatives	38	15
Foreign Exchange Contract | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	230	109
Total liability derivatives	14	6
Other Contract
Derivatives, Fair Value [Line Items]
Total asset derivatives	44	24
Total liability derivatives	17	17
Other Contract | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	25	8
Total liability derivatives	7	7
Other Contract | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	19	16
Total liability derivatives	$ 10	$ 10