Name:	t_ContractDuration
Namespace Prefix:	t_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The First Responder Network Authoritys generally recurring costs associated with normal operations expenses adjusted for inflation over the life of the contract. This estimate was calculated by the reporting entity.

No definition available.

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

- References

No definition available.

Name:	t_GovernmentContractsSubjectToRenegotiationLineItems
Namespace Prefix:	t_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Reinvestment payment period of a contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	t_ReinvestmentPaymentPeriod
Namespace Prefix:	t_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The total sustainability payment commitment paid based on the number of states that have opted-in to the program.

No definition available.

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

Sustainability Payment Commitment, Estimated Network Reinvestment Amount

No definition available.

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

Sustainability Payment Commitment, Network Reinvestment Amount

No definition available.

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

Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 27
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479777/606-10-55-27

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

Amount of contractual obligation, including, but not limited to, long-term debt, lease obligation, purchase obligation, and other commitments.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3

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

Amount of contractual obligation to be paid after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.

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

Amount of contractual obligation to be paid in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.

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

Amount of contractual obligation to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.

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

Amount of contractual obligation to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.

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

Amount of contractual obligation to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.

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

Amount of contractual obligation to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.