Financial Instruments - Fair Value Measurements (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Financial assets and financial liabilities measured at fair value on a recurring basis:
Debt securities - current	$ 872	$ 618
Derivative assets	694	731
Derivative liabilities	705	383
Potential reduction in net position of total derivative assets	353	267
Recurring
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	14,209	7,704
Equity investments	0	0
Debt securities - current	872	618
Derivative assets	694	731
Total assets	15,776	9,053
Derivative liabilities	705	383
Potential reduction in net position of total derivative assets	353	267
Potential reduction in net position of total derivative liabilities	353	267
Recurring \| Prepaid expenses and other current assets
Financial assets and financial liabilities measured at fair value on a recurring basis:
Derivative assets	346	385
Recurring \| Investments and sundry assets
Financial assets and financial liabilities measured at fair value on a recurring basis:
Derivative assets	348	347
Recurring \| Other accrued expenses and liabilities
Financial assets and financial liabilities measured at fair value on a recurring basis:
Derivative liabilities	316	177
Recurring \| Other liabilities
Financial assets and financial liabilities measured at fair value on a recurring basis:
Derivative liabilities	389	206
Recurring \| Time deposits and certificates of deposit
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	12,686	7,679
Recurring \| Money market funds
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	25	25
Recurring \| U.S. government securities
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	1,498
Recurring \| Level 1
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	25	25
Equity investments	0	0
Derivative assets	4	1
Total assets	29	26
Derivative liabilities		40
Recurring \| Level 1 \| Money market funds
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	25	25
Recurring \| Level 2
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	14,184	7,679
Debt securities - current	872	618
Derivative assets	690	731
Total assets	15,747	9,028
Derivative liabilities	705	343
Recurring \| Level 2 \| Time deposits and certificates of deposit
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	12,686	$ 7,679
Recurring \| Level 2 \| U.S. government securities
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	$ 1,498

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and elected not to be offset.

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Fair value of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be offset, deducted from derivative assets.

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Fair value of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be offset, deducted from derivative liabilities.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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