v3.26.1
Long-Term Debt and Credit Facilities - Third Credit Agreement Refinancing (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Long-term Debt and Credit Facilities          
Net loss on early retirement of debt $ (6) $ 236 $ 220 $ 271  
Level 3 Financing, Inc. | Term Loan | Term Loan B-5          
Long-term Debt and Credit Facilities          
Outstanding debt 2,400   2,400   $ 2,400
Level 3 Financing, Inc. | Term Loan | Term Loan B-3          
Long-term Debt and Credit Facilities          
Net loss on early retirement of debt $ 4   $ 4