Stock-Based Compensation (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||||
| Total stock-based compensation | $ 15 | $ 20 | $ 31 | $ 40 |
| Research and development | ||||
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||||
| Total stock-based compensation | 8 | 10 | 16 | 20 |
| General and administrative | ||||
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||||
| Total stock-based compensation | $ 7 | $ 10 | $ 15 | $ 20 |