v3.25.2
Revenues - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Millions
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Dec. 31, 2021
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2020
Dec. 31, 2024
Dec. 31, 2023
Disaggregation of Revenue [Line Items]                
Contract with customer, liability   $ 131   $ 131     $ 319  
Deferred revenue, transaction price   256   256        
Contract with customer, liability, cumulative catch-up adjustment to revenue, change in measure of progress and change in estimate of transaction price   $ 143   $ 143        
Contract with customer, liability, cumulative catch-up adjustment to revenue, earnings per share, diluted (in dollars per share)   $ 1.35   $ 1.40        
Contract with customer, liability, cumulative catch-up adjustment to revenue, earnings per share, basic (in dollars per share)   $ 1.35   $ 1.40        
Deferred revenue, non-refundable payment $ 725              
Total revenues   $ 160 $ 39 $ 188 $ 184      
Access rights and option continuation periods                
Disaggregation of Revenue [Line Items]                
Total revenues   5 9 11 17      
Gilead | R&D services                
Disaggregation of Revenue [Line Items]                
Total revenues   152 25 172 156      
Gilead | Access rights and option continuation periods                
Disaggregation of Revenue [Line Items]                
Current and future programs exclusive access period           10 years    
Contingent milestone payments receivable           $ 300    
Option continuation payment receivable upon sixth anniversary of agreement           $ 100    
Gilead | Rights to certain studies                
Disaggregation of Revenue [Line Items]                
Contract with customer, liability   17   17        
Gilead | R&D Activities for Inflammation Programs                
Disaggregation of Revenue [Line Items]                
Total revenues   $ 3 $ 2 $ 5 $ 4      
Gilead | Revenue Benchmark | Customer Concentration Risk                
Disaggregation of Revenue [Line Items]                
Percentage of revenues   100.00% 92.00% 100.00% 96.00%      
STAR-221 Development Activities | Taiho Collaboration Agreement                
Disaggregation of Revenue [Line Items]                
Contract with customer, liability               $ 35