Revenues - Summary of Revenues by Collaboration, Category of Revenue and Method of Recognition (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
License And Collaboration Agreements [Line Items]
Total revenues	$ 29	$ 27	$ 54	$ 45
Gilead Collaboration, License and R&D services
License And Collaboration Agreements [Line Items]
Total revenues	20	17	37	25
Gilead Collaboration, Access Rights
License And Collaboration Agreements [Line Items]
Total revenues	$ 9	9	$ 17	17
Taiho Collaboration, Access Rights
License And Collaboration Agreements [Line Items]
Total revenues		$ 1		$ 3