Investments and Fair Value Measurement - Fair Value on a Recurring Basis (Details) - Recurring - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Financial Assets
Non-marketable debt securities	$ 3,143	$ 2,955
Total financial assets	7,942	8,157
Money market funds
Financial Assets
Cash and cash equivalents	4,778	5,104
Commercial paper
Financial Assets
Non-marketable debt securities	355	233
U.S. government and agency securities
Financial Assets
Non-marketable debt securities	269	153
Corporate bonds
Financial Assets
Non-marketable debt securities	403	199
Non-marketable debt securities
Financial Assets
Non-marketable debt securities	2,116	2,370
Non-marketable equity securities
Financial Assets
Non-marketable equity securities	21	98
Level 1
Financial Assets
Total financial assets	4,778	5,104
Level 1 \| Money market funds
Financial Assets
Cash and cash equivalents	4,778	5,104
Level 1 \| Commercial paper
Financial Assets
Non-marketable debt securities	0	0
Level 1 \| U.S. government and agency securities
Financial Assets
Non-marketable debt securities	0	0
Level 1 \| Corporate bonds
Financial Assets
Non-marketable debt securities	0	0
Level 1 \| Non-marketable debt securities
Financial Assets
Non-marketable debt securities	0	0
Level 1 \| Non-marketable equity securities
Financial Assets
Non-marketable equity securities	0	0
Level 2
Financial Assets
Total financial assets	1,027	585
Level 2 \| Money market funds
Financial Assets
Cash and cash equivalents	0	0
Level 2 \| Commercial paper
Financial Assets
Non-marketable debt securities	355	233
Level 2 \| U.S. government and agency securities
Financial Assets
Non-marketable debt securities	269	153
Level 2 \| Corporate bonds
Financial Assets
Non-marketable debt securities	403	199
Level 2 \| Non-marketable debt securities
Financial Assets
Non-marketable debt securities	0	0
Level 2 \| Non-marketable equity securities
Financial Assets
Non-marketable equity securities	0	0
Level 3
Financial Assets
Total financial assets	2,137	2,468
Level 3 \| Money market funds
Financial Assets
Cash and cash equivalents	0	0
Level 3 \| Commercial paper
Financial Assets
Non-marketable debt securities	0	0
Level 3 \| U.S. government and agency securities
Financial Assets
Non-marketable debt securities	0	0
Level 3 \| Corporate bonds
Financial Assets
Non-marketable debt securities	0	0
Level 3 \| Non-marketable debt securities
Financial Assets
Non-marketable debt securities	2,116	2,370
Level 3 \| Non-marketable equity securities
Financial Assets
Non-marketable equity securities	$ 21	$ 98

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).

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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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