Fair Value Measurement of Assets and Liabilities - Financial Assets and Liabilities Measured at Fair Value, Recurring (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Assets:
Equity investment	$ 9,279	$ 0
Short-term investments
Assets:
Equity investment	793	0
Recurring
Assets:
Cash and cash equivalents	1,244	1,101
Equity investment	9,279
Derivatives	1,573	1,113
Total financial assets	16,791	4,892
Liabilities:
Derivatives	9	44
Recurring \| Short-term investments
Assets:
Investments	4,038	2,392
Recurring \| Long-term Investments
Assets:
Investments	657	286
Recurring \| Restricted cash \| Short-term investments
Assets:
Investments	22	137
Recurring \| Corporate debt securities \| Short-term investments
Assets:
Investments	3,198	2,255
Recurring \| Corporate debt securities \| Long-term Investments
Assets:
Investments	554	286
Recurring \| Government and agency securities \| Short-term investments
Assets:
Investments	25
Recurring \| Government and agency securities \| Long-term Investments
Assets:
Investments	103
Recurring \| Equity investments with readily determinable fair values \| Short-term investments
Assets:
Investments	793
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash and cash equivalents	1,244	890
Equity investment	9,279
Derivatives	0	0
Total financial assets	11,338	1,027
Liabilities:
Derivatives	0	0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Short-term investments
Assets:
Investments	815	137
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Long-term Investments
Assets:
Investments	0	0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Restricted cash \| Short-term investments
Assets:
Investments	22	137
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Corporate debt securities \| Short-term investments
Assets:
Investments	0	0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Corporate debt securities \| Long-term Investments
Assets:
Investments	0	0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Government and agency securities \| Short-term investments
Assets:
Investments	0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Government and agency securities \| Long-term Investments
Assets:
Investments	0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Equity investments with readily determinable fair values \| Short-term investments
Assets:
Investments	793
Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Cash and cash equivalents	0	211
Equity investment	0
Derivatives	139	62
Total financial assets	4,019	2,814
Liabilities:
Derivatives	9	44
Recurring \| Significant Other Observable Inputs (Level 2) \| Short-term investments
Assets:
Investments	3,223	2,255
Recurring \| Significant Other Observable Inputs (Level 2) \| Long-term Investments
Assets:
Investments	657	286
Recurring \| Significant Other Observable Inputs (Level 2) \| Restricted cash \| Short-term investments
Assets:
Investments	0	0
Recurring \| Significant Other Observable Inputs (Level 2) \| Corporate debt securities \| Short-term investments
Assets:
Investments	3,198	2,255
Recurring \| Significant Other Observable Inputs (Level 2) \| Corporate debt securities \| Long-term Investments
Assets:
Investments	554	286
Recurring \| Significant Other Observable Inputs (Level 2) \| Government and agency securities \| Short-term investments
Assets:
Investments	25
Recurring \| Significant Other Observable Inputs (Level 2) \| Government and agency securities \| Long-term Investments
Assets:
Investments	103
Recurring \| Significant Other Observable Inputs (Level 2) \| Equity investments with readily determinable fair values \| Short-term investments
Assets:
Investments	0
Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents	0	0
Equity investment	0
Derivatives	1,434	1,051
Total financial assets	1,434	1,051
Liabilities:
Derivatives	0	0
Recurring \| Significant Unobservable Inputs (Level 3) \| Short-term investments
Assets:
Investments	0	0
Recurring \| Significant Unobservable Inputs (Level 3) \| Long-term Investments
Assets:
Investments	0	0
Recurring \| Significant Unobservable Inputs (Level 3) \| Restricted cash \| Short-term investments
Assets:
Investments	0	0
Recurring \| Significant Unobservable Inputs (Level 3) \| Corporate debt securities \| Short-term investments
Assets:
Investments	0	0
Recurring \| Significant Unobservable Inputs (Level 3) \| Corporate debt securities \| Long-term Investments
Assets:
Investments	0	$ 0
Recurring \| Significant Unobservable Inputs (Level 3) \| Government and agency securities \| Short-term investments
Assets:
Investments	0
Recurring \| Significant Unobservable Inputs (Level 3) \| Government and agency securities \| Long-term Investments
Assets:
Investments	0
Recurring \| Significant Unobservable Inputs (Level 3) \| Equity investments with readily determinable fair values \| Short-term investments
Assets:
Investments	$ 0

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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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, after the 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 not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a 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. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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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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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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