Derivative Instruments and Hedging Activities - Part 2 (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Liabilities
Derivative Liabilities, Gross	$ 221	$ 315
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	356	348
Other Current Assets [Member]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	74	84
Other Current Liabilities [Member]
Liabilities
Derivative Liabilities, Gross	69	211
Other Noncurrent Assets [Member]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	282	264
Other Noncurrent Liabilities [Member]
Liabilities
Derivative Liabilities, Gross	152	104
Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	190	138
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	94	57
Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	31	177
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	262	291
Interest Rate Contract [Member]
Liabilities
Derivative Liabilities, Gross	161	262
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	70	15
Interest Rate Contract [Member] | Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	159	125
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	68	15
Interest Rate Contract [Member] | Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	2	137
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	2	0
Cross currency derivatives [Member]
Liabilities
Derivative Liabilities, Gross	2	3
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	26	29
Cross currency derivatives [Member] | Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	2	3
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	26	29
Cross currency derivatives [Member] | Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	0	0
Foreign Exchange Contract [Member]
Liabilities
Derivative Liabilities, Gross	54	30
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	243	269
Foreign Exchange Contract [Member] | Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	29	1
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	0	8
Foreign Exchange Contract [Member] | Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	25	29
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	243	261
Commodity Contract [Member]
Liabilities
Derivative Liabilities, Gross	4	20
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	17	35
Commodity Contract [Member] | Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	0	9
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	0	5
Commodity Contract [Member] | Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	4	11
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	$ 17	$ 30