v3.26.3
Device Payment Plan Agreement and Wireless Service Receivables - Schedule of Credit Quality Indicators (Details) - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2026
Dec. 31, 2025
Device payment plan agreement receivables, at amortized cost    
Device payment plan agreement receivables, at amortized cost $ 32,055 $ 34,004
Device payment plan agreement    
Device payment plan agreement receivables, at amortized cost    
2026 12,593  
2025 13,549  
2024 and prior 4,898  
Device payment plan agreement receivables, at amortized cost 31,040  
Gross write-offs    
2026 158  
2025 585  
2024 and prior 326  
Gross write-offs 1,069  
Wireless Service Plan Receivables    
Device payment plan agreement receivables, at amortized cost    
2026 6,219  
2025 57  
Device payment plan agreement receivables, at amortized cost 6,276  
Gross write-offs    
2026 238  
2025 and prior 191  
Gross write-offs 429  
New customers | Device payment plan agreement    
Device payment plan agreement receivables, at amortized cost    
2026 2,776  
2025 2,448  
2024 and prior 757  
Device payment plan agreement receivables, at amortized cost 5,981  
Gross write-offs    
2026 143  
2025 386  
2024 and prior 142  
Gross write-offs 671  
Existing customers | Device payment plan agreement    
Device payment plan agreement receivables, at amortized cost    
2026 9,817  
2025 11,101  
2024 and prior 4,141  
Device payment plan agreement receivables, at amortized cost 25,059  
Gross write-offs    
2026 15  
2025 199  
2024 and prior 184  
Gross write-offs $ 398