v3.20.4

Stockholders' Equity (Narrative) (Details) $ / shares in Units, € / shares in Thousands, $ in Millions |  |  | 1 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | ---
Nov. 06, 2020 USD ($) | Oct. 31, 2020 USD ($) | Dec. 31, 2020 USD ($) $ / shares shares | Sep. 30, 2020 USD ($) period | Dec. 31, 2019 USD ($) $ / shares shares | Sep. 30, 2019 USD ($) | Dec. 31, 2020 USD ($) $ / shares shares | Dec. 31, 2019 USD ($) period $ / shares shares | Dec. 31, 2018 USD ($) $ / shares | Dec. 31, 2020 € / shares shares
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Common stock, authorized (in shares) | shares |  |  | 14,000,000,000 |  | 14,000,000,000 |  | 14,000,000,000 | 14,000,000,000 |  | 14,000,000,000
Preferred stock, authorized (in shares) | shares |  |  | 10,000,000 |  | 10,000,000 |  | 10,000,000 | 10,000,000 |  | 10,000,000
Common stock, par value (in dollars per share) | $ / shares |  |  | $ 1 |  | $ 1 |  | $ 1 | $ 1 |  |
Preferred stock, par value (in dollars per share) | $ / shares |  |  | $ 1 |  | $ 1 |  | $ 1 | 1 |  |
Period post issuance date that preferred shares are optionally redeemable at liquidation price |  |  |  |  |  |  | 5 years |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Repurchase of common stock (in shares) | shares |  |  |  |  |  |  | 142,000,000 |  |  |
Amount repurchased |  |  |  |  |  |  | $ 5,278 |  |  |
Preferred stock, quarterly dividend declared |  |  | $ 36 |  | $ 8 |  |  |  |  |
Common stock, quarterly dividend declared per common shares (in dollars per share) | $ / shares |  |  | $ 0.52 |  | $ 0.52 |  | $ 2.08 | $ 2.05 | $ 2.01 |
Noncontrolling Interest [Line Items] |  |  |  |  |  |  |  |  |  |
Redemption of nonconvertible cumulative preferred interests in subsidiary |  |  |  |  |  |  | $ 1,950 | $ 0 | $ 0 |
Discontinued Operations, Disposed of by Sale | Puerto Rico And U.S. Virgin Islands Operations |  |  |  |  |  |  |  |  |  |
Noncontrolling Interest [Line Items] |  |  |  |  |  |  |  |  |  |
Redemption of nonconvertible cumulative preferred interests in subsidiary | $ 1,950 | $ 1,950 |  |  |  |  |  |  |  |
Stock Repurchase Program, March 2013 |  |  |  |  |  |  |  |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Shares authorized for repurchase (in shares) | shares |  |  | 300,000,000 |  |  |  | 300,000,000 |  |  | 300,000,000
Stock Repurchase Program, March 2014 |  |  |  |  |  |  |  |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Shares authorized for repurchase (in shares) | shares |  |  | 300,000,000 |  |  |  | 300,000,000 |  |  | 300,000,000
Amount outstanding (in shares) | shares |  |  | 178,000,000 |  |  |  | 178,000,000 |  |  | 178,000,000
Tower Holdings |  |  |  |  |  |  |  |  |  |
Noncontrolling Interest [Line Items] |  |  |  |  |  |  |  |  |  |
Preferred interest issued |  |  |  |  | $ 6,000 |  |  | 6,000 |  |
Fixed future purchase option price |  |  |  |  |  |  |  | $ 6,000 |  |
Distribution reset period |  |  |  |  |  |  |  | 5 years |  |
Period post issuance date that preferred interests can be called at issue price |  |  |  |  |  |  |  | 5 years |  |
Option to require redemption, certain contingent events, failure of subsidiary to pay preferred distributions, minimum number of periods | period |  |  |  |  |  |  |  | 2 |  |
Telco LLC |  |  |  |  |  |  |  |  |  |
Noncontrolling Interest [Line Items] |  |  |  |  |  |  |  |  |  |
Preferred interest issued |  |  |  | $ 2,000 |  |  |  |  |  |
Initial preferred distribution percentage |  |  |  | 4.25% |  |  |  |  |  |
Distribution reset period |  |  |  | 7 years |  |  |  |  |  |
Period post issuance date that preferred interests can be called at issue price |  |  |  | 7 years |  |  |  |  |  |
Option to require redemption, certain contingent events, failure of subsidiary to pay preferred distributions, minimum number of periods | period |  |  |  | 2 |  |  |  |  |  |
PR Holdings |  |  |  |  |  |  |  |  |  |
Noncontrolling Interest [Line Items] |  |  |  |  |  |  |  |  |  |
Preferred interest issued |  |  |  |  | $ 1,950 |  |  | $ 1,950 |  |
Initial preferred distribution percentage |  |  |  |  |  |  |  | 4.75% |  |
Preferred Stock – Series A |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Preferred stock, outstanding (in shares) | shares |  |  | 48,000 |  | 48,000 |  | 48,000 | 48,000 |  | 48,000
Preferred stock, liquidation preference per share (in dollars/Euros per share) | $ / shares |  |  | $ 25,000 |  |  |  | $ 25,000 |  |  |
Preferred stock, dividend rate |  |  |  |  |  |  | 5.00% |  |  |
Preferred Stock – Series A | Mobility II, LLC |  |  |  |  |  |  |  |  |  |
Noncontrolling Interest [Line Items] |  |  |  |  |  |  |  |  |  |
Preferred interest, securities issued (in shares) | shares |  |  | 320,000,000 |  |  |  | 320,000,000 |  |  | 320,000,000
Preferred interest distributions |  |  |  |  |  |  | $ 560 |  |  |
Put or redemption option, minimum exercise price calculation, value added to accrued and unpaid distributions (in dollars per share) | $ / shares |  |  |  |  |  |  | $ 25 |  |  |
Put or redemption option, minimum exercise price calculation, value added to accrued and unpaid distributions in the aggregate |  |  |  |  |  |  | $ 8,000 |  |  |
Maximum shares of common stock required to deliver to settle put and redemption options (in shares) | shares |  |  |  |  |  |  | 250,000,000 |  |  |
Class A-1 | Tower Holdings |  |  |  |  |  |  |  |  |  |
Noncontrolling Interest [Line Items] |  |  |  |  |  |  |  |  |  |
Preferred interest issued |  |  |  |  |  | $ 1,500 |  |  |  |
Initial preferred distribution percentage |  |  |  |  |  | 5.00% |  |  |  |
Class A-2 | Tower Holdings |  |  |  |  |  |  |  |  |  |
Noncontrolling Interest [Line Items] |  |  |  |  |  |  |  |  |  |
Preferred interest issued |  |  |  |  | $ 4,500 |  |  | $ 4,500 |  |
Initial preferred distribution percentage |  |  |  |  | 4.75% |  |  |  |  |
Preferred Stock – Series B |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Preferred stock, outstanding (in shares) | shares |  |  | 20,000 |  | 0 |  | 20,000 | 0 |  | 20,000
Preferred stock, liquidation preference per share (in dollars/Euros per share) | € / shares |  |  |  |  |  |  |  |  |  | € 100
Preferred stock, dividend rate |  |  |  |  |  |  | 2.875% |  |  |
Preferred Stock – Series C |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Preferred stock, outstanding (in shares) | shares |  |  | 70,000 |  | 0 |  | 70,000 | 0 |  | 70,000
Preferred stock, liquidation preference per share (in dollars/Euros per share) | $ / shares |  |  | $ 25,000 |  |  |  | $ 25,000 |  |  |
Preferred stock, dividend rate |  |  |  |  |  |  | 4.75% |  |  |

X
- Definition Represent the fixed future purchase option price. + References No definition available. + Details
Name: | t_FixedFuturePurchaseOptionPrice
Namespace Prefix: | t_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Total number of nonredeemable preferred securities (or preferred securities redeemable solely at the option of the issuer) issued by the subsidiary to noncontrolling interest owners. May be all or portion of the number of preferred securities authorized. + References No definition available. + Details
Name: | t_MinorityInterestPreferredStockSharesIssued
Namespace Prefix: | t_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Noncontrolling Interest, Preferred Stock, Callable At Issue Price, Period Post Issuance + References No definition available. + Details
Name: | t_NoncontrollingInterestPreferredStockCallableAtIssuePricePeriodPostIssuance
Namespace Prefix: | t_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Noncontrolling Interest, Preferred Stock, Distribution Reset Period + References No definition available. + Details
Name: | t_NoncontrollingInterestPreferredStockDistributionResetPeriod
Namespace Prefix: | t_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Noncontrolling Interest, Preferred Stock, Initial Preferred Distribution Percentage + References No definition available. + Details
Name: | t_NoncontrollingInterestPreferredStockInitialPreferredDistributionPercentage
Namespace Prefix: | t_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Noncontrolling Interest, Preferred Stock, Maximum Shares Of Common Stock Required To Deliver To Settle Put And Redemption Options + References No definition available. + Details
Name: | t_NoncontrollingInterestPreferredStockMaximumSharesOfCommonStockRequiredToDeliverToSettlePutAndRedemptionOptions
Namespace Prefix: | t_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Noncontrolling Interest, Preferred Stock, Put Or Redemption Option, Minimum Exercise Price Calculation, Value Added To Accrued And Unpaid Distributions + References No definition available. + Details
Name: | t_NoncontrollingInterestPreferredStockPutOrRedemptionOptionMinimumExercisePriceCalculationValueAddedToAccruedAndUnpaidDistributions
Namespace Prefix: | t_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Noncontrolling Interest, Preferred Stock, Put Or Redemption Option, Minimum Exercise Price Calculation, Value Added To Accrued And Unpaid Distributions, Per Share + References No definition available. + Details
Name: | t_NoncontrollingInterestPreferredStockPutOrRedemptionOptionMinimumExercisePriceCalculationValueAddedToAccruedAndUnpaidDistributionsPerShare
Namespace Prefix: | t_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Noncontrolling Interest, Preferred Stock, Required Redemption Option, Failure To Pay Preferred Distribution, Minimum Number Of Periods + References No definition available. + Details
Name: | t_NoncontrollingInterestPreferredStockRequiredRedemptionOptionFailureToPayPreferredDistributionMinimumNumberOfPeriods
Namespace Prefix: | t_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Preferred Stock, Optionally Redeemable At Liquidation Price, Period Post Issuance + References No definition available. + Details
Name: | t_PreferredStockOptionallyRedeemableAtLiquidationPricePeriodPostIssuance
Namespace Prefix: | t_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- 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 No definition available. + Details
Name: | us-gaap_ClassOfStockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate dividends declared during the period for each share of common stock outstanding. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 + Details
Name: | us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face amount or stated value per share of common stock. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The maximum number of common shares permitted to be issued by an entity's charter and bylaws. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of paid and unpaid preferred stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 405 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6957935&loc=d3e64057-112817 + Details
Name: | us-gaap_DividendsPreferredStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- 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 No definition available. + Details
Name: | us-gaap_EquityClassOfTreasuryStockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of noncontrolling interest in subsidiary represented by preferred securities issued by the subsidiary. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(31)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(24)) -URI http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(22)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_MinorityInterestAmountRepresentedByPreferredStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Decrease in noncontrolling interest balance from payment of dividends or other distributions by the non-wholly owned subsidiary or partially owned entity, included in the consolidation of the parent entity, to the noncontrolling interest holders. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 + Details
Name: | us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- 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 No definition available. + Details
Name: | us-gaap_MinorityInterestLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash outflow during the period for redemption of redeemable noncontrolling interests. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585 + Details
Name: | us-gaap_PaymentsForRepurchaseOfRedeemableNoncontrollingInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The percentage rate used to calculate dividend payments on preferred stock. + References No definition available. + Details
Name: | us-gaap_PreferredStockDividendRatePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The per share liquidation preference (or restrictions) of nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) that has a preference in involuntary liquidation considerably in excess of the par or stated value of the shares. The liquidation preference is the difference between the preference in liquidation and the par or stated values of the share. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(d)(1)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(d)(1)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21484-112644 + Details
Name: | us-gaap_PreferredStockLiquidationPreference
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_PreferredStockParOrStatedValuePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_PreferredStockSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_PreferredStockSharesOutstanding
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of shares that have been repurchased during the period and are being held in treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_TreasuryStockSharesAcquired
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 + Details
Name: | us-gaap_TreasuryStockValueAcquiredCostMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_DisposalGroupClassificationAxis=us-gaap_DiscontinuedOperationsDisposedOfBySaleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=t_PuertoRicoAndUSVirginIslandsOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareRepurchaseProgramAxis=t_StockRepurchaseProgramMarch2013Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShareRepurchaseProgramAxis=t_StockRepurchaseProgramMarch2014Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=t_TowerHoldingsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=t_TelcoLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=t_PuertoRicoAndUsVirginIslandsWirelineAndWirelessOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_SeriesAPreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=t_ATTMobilityIiLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=t_ClassA1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=t_ClassA2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_SeriesBPreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_SeriesCPreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |