Device Payment Plan Agreement and Wireless Service Receivables - Schedule of Device Payment Plan Agreement Receivables (Detail) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Receivables [Abstract]
Device payment plan agreement receivables, gross	$ 32,055	$ 34,004
Unamortized imputed interest	(1,015)	(1,053)
Device payment plan agreement receivables, at amortized cost	31,040	32,951
Allowance	(1,510)	(1,628)
Device payment plan agreement receivables, net	29,530	31,323
Accounts receivable, net	15,547	15,777
Other assets	$ 13,983	$ 15,546

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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+ Details

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Amortized cost, before allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

+ References

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Amortized cost, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

+ References + Details