v3.25.4
Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Allowance for credit losses deducted from accounts receivable:      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period $ 1,769 $ 1,609 $ 1,261
Charged to Expenses 2,234 2,269 2,146
Charged to Other Accounts 163 113 38
Deductions 2,121 2,222 1,836
Balance at End of Period 2,045 1,769 1,609
Allowance for credit losses deducted from accounts receivable: | Device payment plan agreement      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 617 592  
Balance at End of Period 794 617 592
Valuation allowance for deferred tax assets:      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 1,399 1,341 1,347
Charged to Expenses 84 157 68
Charged to Other Accounts 45 0 13
Deductions 367 99 87
Balance at End of Period $ 1,161 $ 1,399 $ 1,341