Derivative Instruments and Hedging Activities (Assets and LIabilities - Designated vs. Not Designated Hedging Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Total asset derivatives	$ 375	$ 280
Total liability derivatives	490	514
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	38	31
Total liability derivatives	448	490
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	337	249
Total liability derivatives	42	24
Interest Rate Contract
Derivatives, Fair Value [Line Items]
Total liability derivatives	358	416
Interest Rate Contract | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total liability derivatives	358	416
Interest Rate Contract | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total liability derivatives	0	0
Cross Currency Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Total liability derivatives	43	29
Cross Currency Interest Rate Contract [Member] | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total liability derivatives	43	29
Cross Currency Interest Rate Contract [Member] | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total liability derivatives	0	0
Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Total asset derivatives	327	236
Total liability derivatives	56	52
Foreign Exchange Contract [Member] | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	8	6
Total liability derivatives	35	38
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	319	230
Total liability derivatives	21	14
Other Contract
Derivatives, Fair Value [Line Items]
Total asset derivatives	48	44
Total liability derivatives	33	17
Other Contract | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	30	25
Total liability derivatives	12	7
Other Contract | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	18	19
Total liability derivatives	$ 21	$ 10