Device Payment Plan Agreement and Wireless Service Receivables - Schedule of Receivables (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, after Allowance for Credit Loss, Current [Abstract]
Accounts receivable, net of allowance	$ 15,141	$ 13,173
Accounts and Financing Receivable, after Allowance for Credit Loss, Current [Abstract]
Accounts receivable	27,261	26,102
Less Allowance for credit losses	1,152	1,017
Accounts receivable, net	26,109	$ 25,085
Device payment plan agreement
Financing Receivable, after Allowance for Credit Loss, Current [Abstract]
Accounts receivable	15,839
Less Allowance for credit losses	698
Accounts receivable, net of allowance	15,141
Wireless service
Accounts Receivable, after Allowance for Credit Loss, Current [Abstract]
Accounts receivable	5,809
Less Allowance for credit losses	240
Accounts receivable, net	5,569
Other receivables
Accounts Receivable, after Allowance for Credit Loss, Current [Abstract]
Accounts receivable	5,613
Less Allowance for credit losses	214
Accounts receivable, net	$ 5,399