Marketable Securities - Current and Non-current (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale
Current marketable securities	$ 855	$ 404
Non-current marketable securities	30	30
Total marketable securities	885	434
Corporate debt securities
Debt Securities, Available-for-sale
Current marketable securities	0	7
Commercial paper
Debt Securities, Available-for-sale
Current marketable securities	501	237
Certificates of deposit/time deposits
Debt Securities, Available-for-sale
Current marketable securities	45	31
U.S. treasury securities
Debt Securities, Available-for-sale
Current marketable securities	305	125
U.S. municipal securities
Debt Securities, Available-for-sale
Current marketable securities	4	4
Non-current marketable securities	$ 30	$ 30

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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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