Financial Instruments (Fair Value of Foreign Exchange Contracts) (Details) - Foreign Exchange Contract [Member] - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 813	$ 574
Liability Derivatives	163	172
Designated as Hedging Instrument [Member] | Other current assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	207	301
Designated as Hedging Instrument [Member] | Other accrued liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	66	26
Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	436	181
Designated as Hedging Instrument [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	36	117
Not Designated as Hedging Instrument [Member] | Other current assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	161	7
Not Designated as Hedging Instrument [Member] | Other accrued liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	61	29
Not Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	9	85
Not Designated as Hedging Instrument [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 0	$ 0