Name:	t_ReductionsInOtherAssetsAmountGross
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Balance Type:	credit
Period Type:	duration

Amount of significant reductions in the period of other assets (current, noncurrent, or unclassified), net of allowance, imputed interest and trade-in right guarantees.

No definition available.

Name:	t_ReductionsInOtherAssetsAmountNet
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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.

No definition available.

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

Amount charged against operating income increasing loss contingency liability, after adjustments to reduce previously estimated charges.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349

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The cash inflow associated with the sale of receivables arising from the financing of goods and services.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3179-108585

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A device of credit enhancement where a part of the purchase price for the receivable/ payable is retained to serve as a cash collateral.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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