Investments and Fair Value Measurement - Fair Value of Unobservable Inputs, Assets (Details) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2019
USD ($)
| |
| Non-marketable Debt Securities | |
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | |
| Balance as of December 31, 2018 | $ 2,370 |
| Total net gains (losses) | |
| Included in earnings | (8) |
| Included in other comprehensive income (loss) | 4 |
| Purchases | 4 |
| Transfers | 0 |
| Balance as of December 31, 2019 | 2,370 |
| Non-marketable equity securities | |
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | |
| Balance as of December 31, 2018 | 0 |
| Total net gains (losses) | |
| Included in earnings | 11 |
| Included in other comprehensive income (loss) | 0 |
| Purchases | 56 |
| Transfers | 31 |
| Balance as of December 31, 2019 | $ 98 |