Income Taxes (Changes In Unrecognized Tax Benefits Balance For Federal State And Foreign Tax) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Unrecognized Tax Benefits [Roll Forward]
Balance at beginning of year	$ 11,924	$ 9,657
Increases for tax positions related to the current year	369	1,026
Increases for tax positions related to prior years	1,017	448
Decreases for tax positions related to prior years	(772)	(212)
Lapse of statute of limitations	(8)	(16)
Settlements	3	1,021
Balance at end of year	12,533	11,924
Accrued interest and penalties	2,223	1,785
Gross unrecognized income tax benefits	14,756	13,709
Less: Deferred federal and state income tax benefits	(849)	(687)
Less: Tax attributable to timing items included above	(6,964)	(6,438)
Total UTB that, if recognized, would impact the effective income tax rate as of the end of the year	$ 6,943	$ 6,584

The entity's net deferred tax assets and liabilities (federal and state) pertaining to continuing operations.

No definition available.

Name:	t_DeferredFederalAndStateIncomeTaxBenefits
Namespace Prefix:	t_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The gross amount of unrecognized tax benefits (tax reductions recognized in financial reports but excluded from tax returns) pertaining to uncertain tax positions taken in tax returns as of the beginning balance sheet date, excluding amounts pertaining to deferred income tax benefits and timing.

+ References

No definition available.

+ Details

Name:	t_GrossUnrecognizedTaxBenefits
Namespace Prefix:	t_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The net amount of change in unrecognized tax benefits resulting from settlements with taxing authorities.

+ References

No definition available.

+ Details

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

- Definition

The tax impact of reconciling items included in Unrecognized Tax Benefits.

+ References

No definition available.

+ Details

Name:	t_UnrecognizedTaxDueToTimingIssues
Namespace Prefix:	t_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 217
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482663/740-10-55-217

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-15A

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 10B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482525/740-10-45-10B

+ Details

Name:	us-gaap_UnrecognizedTaxBenefits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

+ Details

Name:	us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

+ References

+ Details

Name:	us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

+ Details

Name:	us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

+ Details

Name:	us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15A
-Subparagraph (a)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-15A

+ Details

Name:	us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

+ References

+ Details

Name:	us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant