Derivative Instruments and Hedging Activities - Part 2 (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Liabilities
Derivative Liabilities, Gross	$ 253	$ 315
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	360	348
Other Current Assets [Member]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	70	84
Other Current Liabilities [Member]
Liabilities
Derivative Liabilities, Gross	170	211
Other Noncurrent Assets [Member]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	290	264
Other Noncurrent Liabilities [Member]
Liabilities
Derivative Liabilities, Gross	83	104
Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	92	138
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	99	57
Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	161	177
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	261	291
Interest Rate Contract [Member]
Liabilities
Derivative Liabilities, Gross	210	262
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	42	15
Interest Rate Contract [Member] | Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	90	125
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	41	15
Interest Rate Contract [Member] | Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	120	137
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	1	0
Cross currency derivatives [Member]
Liabilities
Derivative Liabilities, Gross	1	3
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	45	29
Cross currency derivatives [Member] | Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	1	3
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	45	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	41	30
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	262	269
Foreign Exchange Contract [Member] | Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	1	1
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	13	8
Foreign Exchange Contract [Member] | Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	40	29
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	249	261
Commodity Contract [Member]
Liabilities
Derivative Liabilities, Gross	1	20
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	11	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	1	11
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	$ 11	$ 30