The following tables summarize the Company’s investments by major security type (in millions):
| | | | | | | | | | | | | | | | December 31, 2022 | | Amortized
Cost | Gross
Unrealized
Gains | Gross
Unrealized
Losses | Total
Estimated
Fair Value | | Short-term investments | | | | | | Debt securities: | | | | | | Certificates of deposit | $ | 573 | | $ | — | | $ | — | | $ | 573 | | | Government bonds | 83 | | — | | — | | 83 | | | Commercial paper | 574 | | — | | — | | 574 | | | Corporate debt securities | 965 | | 1 | | (7) | | 959 | | Mortgage-backed and asset-backed securities | 37 | | — | | (3) | | 34 | | | Total debt securities | 2,232 | | 1 | | (10) | | 2,223 | | | Time deposits | 20 | | — | | — | | 20 | | Equity investments (1) | 1 | | — | | — | | 1 | | Total short-term investments | $ | 2,253 | | $ | 1 | | $ | (10) | | $ | 2,244 | | | | | | | Long-term investments (2) | | | | | | Debt securities: | | | | | | Corporate debt securities | $ | 13 | | $ | — | | $ | (9) | | $ | 4 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | | September 30, 2023 | | Amortized
Cost | Gross
Unrealized
Gains | Gross
Unrealized
Losses | Total
Estimated
Fair Value | | Short-term investments | | | | | | Debt securities: | | | | | Certificates of deposit | $ | 328 | | $ | — | | $ | — | | $ | 328 | | Government bonds | 291 | | — | | — | | 291 | | Commercial paper | 366 | | — | | — | | 366 | | Corporate debt securities | 1,209 | | 1 | | (10) | | 1,200 | | Mortgage-backed and asset-backed securities | 117 | | — | | (6) | | 111 | | | Total debt securities | 2,311 | | 1 | | (16) | | 2,296 | | | Time deposits | 490 | | — | | — | | 490 | | Equity investments (1) | 1 | | — | | — | | 1 | | Total short-term investments | $ | 2,802 | | $ | 1 | | $ | (16) | | $ | 2,787 | | | | | | | Long-term investments (2) | | | | | | Debt securities: | | | | | | Corporate debt securities | $ | 13 | | $ | — | | $ | (9) | | $ | 4 | | | | | | | | | | | | | | | | | | | | | |
(1)Unrealized gain (loss) on equity investments were immaterial for the three and nine months ended September 30, 2022 and 2023. (2)Classified within other assets, noncurrent on the condensed consolidated balance sheets.
|