v3.26.1
Revenue Recognition - Revenue from contracts with customers (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Revenue Recognition    
Revenue $ 256 $ 266
Consumer Revenue, Data    
Revenue Recognition    
Revenue 59 61
Consumer Revenue, Wireless    
Revenue Recognition    
Revenue 36 34
Consumer Revenue, Other    
Revenue Recognition    
Revenue 4 9
Business Revenue, Data    
Revenue Recognition    
Revenue 123 127
Business Revenue, Wireless    
Revenue Recognition    
Revenue 8 8
Business Revenue, Other    
Revenue Recognition    
Revenue 2 3
Lease, grant, and revenue from subsidies    
Revenue Recognition    
Revenue $ 24 $ 24