Revenues - Summary of Revenues by Collaboration, Category of Revenue and Method of Recognition (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
License And Collaboration Agreements [Line Items]
Total revenues	$ 26	$ 48	$ 214	$ 232
Total revenues from collaborations	20	41	192	204
Total revenues from a customer	6	7	22	28
License and R&D services | Gilead collaboration | Over time
License And Collaboration Agreements [Line Items]
Total revenues	23	25	200	185
Access rights | Gilead collaboration | Over time
License And Collaboration Agreements [Line Items]
Total revenues	3	5	14	22
License revenue | Taiho collaboration | Point in time
License And Collaboration Agreements [Line Items]
Total revenues	0	15	0	15
Other | Taiho collaboration | Over time
License And Collaboration Agreements [Line Items]
Total revenues	$ 0	$ 3	$ 0	$ 10