Derivative Instruments and Hedging Activities (Assets and LIabilities - Designated vs. Not Designated Hedging Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Total asset derivatives	$ 171	$ 262
Total liability derivatives	424	257
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	62	35
Total liability derivatives	368	238
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	109	227
Total liability derivatives	56	19
Interest Rate Contract
Derivatives, Fair Value [Line Items]
Total asset derivatives	31	29
Total liability derivatives	328	208
Interest Rate Contract | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	31	29
Total liability derivatives	323	205
Interest Rate Contract | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	0	0
Total liability derivatives	5	3
Cross Currency Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Total asset derivatives	0	6
Total liability derivatives	21	5
Cross Currency Interest Rate Contract [Member] | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	0	6
Total liability derivatives	21	5
Cross Currency Interest Rate Contract [Member] | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	0	0
Total liability derivatives	0	0
Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Total asset derivatives	110	217
Total liability derivatives	44	41
Foreign Exchange Contract [Member] | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	31	0
Total liability derivatives	22	28
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	79	217
Total liability derivatives	22	13
Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Total asset derivatives	30	10
Total liability derivatives	31	3
Commodity Contract [Member] | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	0	0
Total liability derivatives	2	0
Commodity Contract [Member] | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total asset derivatives	30	10
Total liability derivatives	29	3
Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Noncurrent	99	187
Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	$ 72	$ 75