Financial Instruments - Fair Value Measurements (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Financial assets and financial liabilities measured at fair value on a recurring basis:
Debt securities - current	$ 733	$ 618
Derivative assets	536	731
Derivative liabilities	1,074	383
Potential reduction in net position of total derivative assets	316	267
Recurring
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	6,848	7,704
Equity investments	0	0
Debt securities - current	733	618
Debt securities - noncurrent	111
Derivative assets	536	731
Total assets	8,229	9,053
Derivative liabilities	1,074	383
Recurring \| Prepaid expenses and other current assets
Financial assets and financial liabilities measured at fair value on a recurring basis:
Derivative assets	395	385
Recurring \| Investments and sundry assets
Financial assets and financial liabilities measured at fair value on a recurring basis:
Derivative assets	141	347
Recurring \| Other accrued expenses and liabilities
Financial assets and financial liabilities measured at fair value on a recurring basis:
Derivative liabilities	203	177
Recurring \| Other liabilities
Financial assets and financial liabilities measured at fair value on a recurring basis:
Derivative liabilities	870	206
Recurring \| Time deposits and certificates of deposit
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	6,251	7,679
Recurring \| Money market funds
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	597	25
Recurring \| Level 1
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	597	25
Equity investments	0	0
Derivative assets	4	1
Total assets	601	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	597	25
Recurring \| Level 2
Financial assets and financial liabilities measured at fair value on a recurring basis:
Cash equivalents	6,251	7,679
Debt securities - current	733	618
Debt securities - noncurrent	111
Derivative assets	533	731
Total assets	7,628	9,028
Derivative liabilities	1,074	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	$ 6,251	$ 7,679

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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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 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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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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