Financial Instruments (Fair Value of Derivative Contracts) (Details) - Derivative Contract [Member] - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Derivative asset fair value	$ 254	$ 390
Derivative liability fair value	565	419
Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset fair value	164	319
Designated as Hedging Instrument [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset fair value	35	21
Designated as Hedging Instrument [Member] | Other Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability fair value	89	23
Designated as Hedging Instrument [Member] | Income Taxes and Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability fair value	351	301
Not Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset fair value	55	50
Not Designated as Hedging Instrument [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset fair value	0	0
Not Designated as Hedging Instrument [Member] | Other Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability fair value	90	70
Not Designated as Hedging Instrument [Member] | Income Taxes and Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability fair value	$ 35	$ 25