Sales Of Receivables (Finance Receivables Repurchased) (Details) - Equipment Installment - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair value of repurchased receivables	$ 3,185	$ 2,997	$ 3,314
Carrying value of beneficial interests	3,199	3,013	3,335
Gain on repurchases	$ (14)	$ (16)	$ (21)

Reflects the net positive or negative amount derived from subtracting from fair value the carrying amounts, of notes receivable repurchased and included in Selling, general and administrative in the consolidated statements of income.

No definition available.

+ Details

Name:	t_GainLossOnSaleOfNotesReceivableRepurchased
Namespace Prefix:	t_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

Fair value portion of receivables during period, including, but not limited to, trade account receivables, note receivables, and loan receivables.

+ References

No definition available.

+ Details

Name:	t_ReceivablesFairValueDisclosureDuringPeriod
Namespace Prefix:	t_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 40
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481628/310-20-40-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

+ Details

Name:	us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	t_FinanceReceivableProgramsAxis=t_EquipmentInstallmentProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: