Financial Instruments (Fair Values of Outstanding Derivative Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Derivative Assets:
Derivative Assets	$ 397	$ 366
Derivative Liabilities:
Derivative Liabilities	1,554	403
Level 2:
Derivative Assets:
Derivative Assets	365	345
Derivative Liabilities:
Derivative Liabilities	1,522	382
Level 2: | Other current and non-current assets | Foreign exchange contracts
Derivative Assets:
Derivative Assets	349
Level 2: | Other current and non-current assets | Foreign exchange contracts
Derivative Assets:
Derivative Assets		344
Level 2: | Other current and non-current assets | Other contracts
Derivative Assets:
Derivative Assets	16	1
Level 2: | Accrued expenses and other liabilities, current and non-current | Foreign exchange contracts
Derivative Liabilities:
Derivative Liabilities	580
Level 2: | Accrued expenses and other liabilities, current and non-current | Foreign exchange contracts
Derivative Liabilities:
Derivative Liabilities		369
Level 2: | Accrued expenses and other liabilities, current and non-current | Other contracts
Derivative Liabilities:
Derivative Liabilities	942	13
Fair Value of Derivatives Designated as Hedging Instruments | Level 2:
Derivative Assets:
Derivative Assets	33	91
Derivative Liabilities:
Derivative Liabilities	395	173
Fair Value of Derivatives Designated as Hedging Instruments | Level 2: | Other current and non-current assets | Foreign exchange contracts
Derivative Assets:
Derivative Assets	33
Fair Value of Derivatives Designated as Hedging Instruments | Level 2: | Other current and non-current assets | Foreign exchange contracts
Derivative Assets:
Derivative Assets		91
Fair Value of Derivatives Designated as Hedging Instruments | Level 2: | Other current and non-current assets | Other contracts
Derivative Assets:
Derivative Assets	0	0
Fair Value of Derivatives Designated as Hedging Instruments | Level 2: | Accrued expenses and other liabilities, current and non-current | Foreign exchange contracts
Derivative Liabilities:
Derivative Liabilities	395
Fair Value of Derivatives Designated as Hedging Instruments | Level 2: | Accrued expenses and other liabilities, current and non-current | Foreign exchange contracts
Derivative Liabilities:
Derivative Liabilities		173
Fair Value of Derivatives Designated as Hedging Instruments | Level 2: | Accrued expenses and other liabilities, current and non-current | Other contracts
Derivative Liabilities:
Derivative Liabilities	0	0
Fair Value of Derivatives Not Designated as Hedging Instruments | Level 2:
Derivative Assets:
Derivative Assets	332	254
Derivative Liabilities:
Derivative Liabilities	1,127	209
Fair Value of Derivatives Not Designated as Hedging Instruments | Level 2: | Other current and non-current assets | Foreign exchange contracts
Derivative Assets:
Derivative Assets	316
Fair Value of Derivatives Not Designated as Hedging Instruments | Level 2: | Other current and non-current assets | Foreign exchange contracts
Derivative Assets:
Derivative Assets		253
Fair Value of Derivatives Not Designated as Hedging Instruments | Level 2: | Other current and non-current assets | Other contracts
Derivative Assets:
Derivative Assets	16	1
Fair Value of Derivatives Not Designated as Hedging Instruments | Level 2: | Accrued expenses and other liabilities, current and non-current | Foreign exchange contracts
Derivative Liabilities:
Derivative Liabilities	185
Fair Value of Derivatives Not Designated as Hedging Instruments | Level 2: | Accrued expenses and other liabilities, current and non-current | Foreign exchange contracts
Derivative Liabilities:
Derivative Liabilities		196
Fair Value of Derivatives Not Designated as Hedging Instruments | Level 2: | Accrued expenses and other liabilities, current and non-current | Other contracts
Derivative Liabilities:
Derivative Liabilities	$ 942	$ 13