Marketable Securities and Held-to-Maturity Debt Securities - Current and non-current (Details) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Held-to-Maturity Debt Securities | ||
| Current marketable securities | $ 98 | $ 380 |
| Non-current marketable securities | 43 | 37 |
| Total marketable securities | 141 | 417 |
| Commercial paper | ||
| Held-to-Maturity Debt Securities | ||
| Current marketable securities | 85 | 366 |
| Certificates of deposit/time deposits | ||
| Held-to-Maturity Debt Securities | ||
| Current marketable securities | 10 | 10 |
| U.S. municipal securities | ||
| Held-to-Maturity Debt Securities | ||
| Current marketable securities | 3 | 3 |
| Non-current marketable securities | $ 43 | 37 |
| Asset-backed securities | ||
| Held-to-Maturity Debt Securities | ||
| Current marketable securities | $ 1 |