v3.26.3
Device Payment Plan Agreement and Wireless Service Receivables - Balance and Aging of Receivables (Detail) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Device payment plan agreement receivables, gross $ 32,055 $ 34,004
Device payment plan agreement    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Device payment plan agreement receivables, gross 31,040  
Unbilled | Device payment plan agreement    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Device payment plan agreement receivables, gross 29,485  
Billed | Current | Device payment plan agreement    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Device payment plan agreement receivables, gross 1,201  
Billed | Past due | Device payment plan agreement    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Device payment plan agreement receivables, gross $ 354