v3.26.1
Revenue from contracts with customers - Geographic (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues $ 358 $ 335
Brazil    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues 146 121
United States    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues 103 81
Angola    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues 77 81
Norway    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues 32 23
Other    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues $ 0 $ 29