v3.25.4
Receivables and Related Allowance for Credit Losses - Schedule of Unamortized Imputed Discount and Allowance for Credit Losses for Equipment Installment Plan Receivables (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Roll Forward]      
Allowance for credit losses and imputed discount, beginning of period $ 990 $ 934 $ 978
Bad debt expense 1,370 1,192 898
Write-offs (1,318) (1,155) (964)
Allowance for credit losses for acquired credit deteriorated receivables 88 0 0
Change in imputed discount on short-term and long-term EIP receivables 225 199 220
Impact on the imputed discount from sales of EIP receivables (183) (180) (198)
Allowance for credit losses and imputed discount, end of period 1,172 990 934
Accounts Receivable Allowance      
Financing Receivable, Allowance for Credit Loss [Roll Forward]      
Allowance for credit losses and imputed discount, beginning of period 176 161 167
Bad debt expense 694 592 440
Write-offs (654) (577) (446)
Allowance for credit losses for acquired credit deteriorated receivables 10 0 0
Allowance for credit losses and imputed discount, end of period 226 176 161
EIP Receivables Allowance      
Financing Receivable, Allowance for Credit Loss [Roll Forward]      
Allowance for credit losses and imputed discount, beginning of period 814 773 811
Bad debt expense 676 600 458
Write-offs (664) (578) (518)
Allowance for credit losses for acquired credit deteriorated receivables 78 0 0
Change in imputed discount on short-term and long-term EIP receivables 225 199 220
Impact on the imputed discount from sales of EIP receivables (183) (180) (198)
Allowance for credit losses and imputed discount, end of period $ 946 $ 814 $ 773