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Financial Instruments - Information on Available-for-sale Investments (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2020 | Jun. 30, 2019 | Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, amortized cost | $ 76 |  | $ 76 |  | $ 1,768
Debt securities, unrealized gains | 0 |  | 0 |  | 17
Debt securities, unrealized losses | 0 |  | 0 |  | 0
Debt securities, fair value | 76 |  | 76 |  | 1,785
Publicly traded equity securities, fair value | 1,307 |  | 1,307 |  | 838
Total debt and publicly traded equity securities, fair value | 1,383 |  | 1,383 |  | 2,623
Unrealized net losses (gains) | (464) | $ 39 | (469) | $ (75) |
U.S. government and agency securities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, amortized cost | 74 |  | 74 |  | 266
Debt securities, unrealized gains | 0 |  | 0 |  | 3
Debt securities, unrealized losses | 0 |  | 0 |  | 0
Debt securities, fair value | 74 |  | 74 |  | 269
Foreign government bonds |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, amortized cost | 2 |  | 2 |  | 0
Debt securities, unrealized gains | 0 |  | 0 |  | 0
Debt securities, unrealized losses | 0 |  | 0 |  | 0
Debt securities, fair value | 2 |  | 2 |  | 0
Commercial paper |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, amortized cost | 0 |  | 0 |  | 668
Debt securities, unrealized gains | 0 |  | 0 |  | 0
Debt securities, unrealized losses | 0 |  | 0 |  | 0
Debt securities, fair value | 0 |  | 0 |  | 668
Corporate notes and bonds |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, amortized cost | 0 |  | 0 |  | 608
Debt securities, unrealized gains | 0 |  | 0 |  | 13
Debt securities, unrealized losses | 0 |  | 0 |  | 0
Debt securities, fair value | 0 |  | 0 |  | 621
Asset-backed securities |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Debt securities, amortized cost | 0 |  | 0 |  | 226
Debt securities, unrealized gains | 0 |  | 0 |  | 1
Debt securities, unrealized losses | 0 |  | 0 |  | 0
Debt securities, fair value | $ 0 |  | $ 0 |  | $ 227

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- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 + Details
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- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 + Details
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- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740 + Details
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