Sales Of Receivables (Finance Receivables Repurchased) (Details) - Equipment Installment - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair value of repurchased receivables	$ 732	$ 1,386	$ 2,038	$ 3,314
Carrying value of deferred purchase price	740	1,395	2,051	3,335
Gain on repurchases	$ (8)	$ (9)	$ (13)	$ (21)

Amount, during period, representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale.

No definition available.

Name:	t_NotesReceivableGrossDuringPeriod
Namespace Prefix:	t_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration