v3.26.3
Employee Benefits - Additional Information (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Mar. 31, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Mass Markets Fiber-to-the Home Business          
Employee Benefits          
Recognition of prior service costs (credits)       $ (6)  
Combined Pension Plan          
Employee Benefits          
Settlement charges $ 0   $ 0 9 $ 0
Curtailment gain (loss) 0   0 (5) 0
Recognition of prior service costs (credits) (1)   0 (1) (1)
Contributions   $ 101      
Combined Pension Plan | Mass Markets Fiber-to-the Home Business          
Employee Benefits          
Curtailment gain (loss)       (5)  
Post-Retirement Benefit Plan          
Employee Benefits          
Curtailment gain (loss) 0   0 10 0
Recognition of prior service costs (credits) $ (2)   $ (3) (4) $ (6)
Post-Retirement Benefit Plan | Mass Markets Fiber-to-the Home Business          
Employee Benefits          
Curtailment gain (loss)       10  
Recognition of prior service costs (credits)       $ 1