Revenues - Summary of Revenues by Collaboration, Category of Revenue and Method of Recognition (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
License And Collaboration Agreements [Line Items]
Total revenues	$ 28	$ 145
Total revenues from collaborations	20	135
Total revenues from a customer	8	10
License and R&D services | Gilead collaboration | Over time
License And Collaboration Agreements [Line Items]
Total revenues	20	131
R&D services | Gilead collaboration | Over time
License And Collaboration Agreements [Line Items]
Total revenues	2	2
Access rights | Gilead collaboration | Over time
License And Collaboration Agreements [Line Items]
Total revenues	6	8
Other | Taiho collaboration | Over time
License And Collaboration Agreements [Line Items]
Total revenues	$ 0	$ 4