Preparation Of Interim Financial Statements (Policy)	6 Months Ended
Jun. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation Throughout this document, AT&T Inc. is referred to as “AT&T,” “we” or the “Company.” These consolidated financial statements include all adjustments that are necessary to present fairly the results for the presented interim periods, consisting of normal recurring accruals and other items. The results for the interim periods are not necessarily indicative of those for the full year. You should read this document in conjunction with the consolidated financial statements and accompanying notes included in our Annual Report on Form 10-K for the year ended December 31, 2015. The consolidated financial statements include the accounts of the Company and our majority-owned subsidiaries and affiliates, including the results of DIRECTV and wireless properties in Mexico for the period from acquisition to the reporting date. Our subsidiaries and affiliates operate in the communications and digital entertainment services industry, providing services and equipment that deliver voice, video and broadband services domestically and internationally. All significant intercompany transactions are eliminated in the consolidation process. Investments in less than majority-owned subsidiaries and partnerships where we have significant influence are accounted for under the equity method. Earnings from certain investments accounted for using the equity method are included for periods ended within up to one quarter of our period end. We also record our proportionate share of our equity method investees' other comprehensive income (OCI) items, including cumulative translation adjustments. The preparation of financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes, including estimates of probable losses and expenses. Actual results could differ from those estimates. Certain prior period amounts have been conformed to the current period's presentation, including our 2015 change in accounting to capitalize customer set-up and installation costs and amortize them over the expected economic life of the customer relationship. The consolidated statements of income also include revisions to present “Equipment” and “Broadcast, programming and operations” costs separately from “Other cost of services.”
Leases	Leases In February 2016, the Financial Accounting Standards Board (FASB) issued ASU No. 2016-02, “Leases (Topic 842)” (ASU 2016-02), which replaces existing leasing rules with a comprehensive lease measurement and recognition standard and expanded disclosure requirements. ASU 2016-02 will require lessees to recognize most leases on their balance sheets as liabilities, with corresponding “right-of-use” assets. Leases will be classified as either a finance or an operating lease without relying upon the bright-line tests under current GAAP. Upon initial evaluation, we believe the key change upon adoption will be the balance sheet recognition. The income statement recognition appears similar to our current methodology. ASU 2016-02 becomes effective for annual reporting periods beginning after December 15, 2018, subject to early adoption. We have just begun our evaluation of the impact on our financial statements, as well as available adoption methods, but we believe our implementation of the revenue recognition standard discussed below could influence the timing of our adoption of ASU 2016-02.
Revenue Recognition	Revenue Recognition In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (ASU 2014-09) and has since modified the standard four times. These standards replace existing revenue recognition rules with a comprehensive revenue measurement and recognition standard and expanded disclosure requirements. ASU 2014-09, as amended, becomes effective for annual reporting periods beginning after December 15, 2017, at which point we plan to adopt the standard. The FASB allows two adoption methods under ASU 2014-09. Under one method, a company will apply the rules to contracts in all reporting periods presented, subject to certain allowable exceptions. Under the other method, a company will apply the rules to all contracts existing as of January 1, 2018, recognizing in beginning retained earnings an adjustment for the cumulative effect of the change and providing additional disclosures comparing results to previous rules (“modified retrospective method”). We continue to evaluate the available adoption methods. Upon initial evaluation, we believe the key changes in the standard that impact our revenue recognition relate to the allocation of contract revenues between various services and equipment, and the timing of when those revenues are recognized. We are still in the process of evaluating these impacts. As a result of our accounting policy change for customer set-up and installation costs in 2015, we believe under the new standard that the requirement to defer such costs will not result in a significant change to our results. However, the requirement to defer incremental contract acquisition costs and recognize them over the contract period or expected customer life will result in the recognition of a deferred charge on our balance sheets. We cannot currently estimate the impact of this change upon adoption, as the industry continues to undergo changes in how devices and services are sold to customers.
Customer Fulfillment Costs	Customer Fulfillment Costs During the second quarter of 2016, we updated our analysis of the economic lives of customer relationships, which included a review of satellite customer data following the DIRECTV acquisition. As of April 1, 2016, to better reflect the estimated economic lives of satellite and certain business customer relationships, we extended the period to approximately 4.5 years. This change in accounting estimate decreased other cost of services and impacted net income $82, or $0.01 per diluted share, in the second quarter of 2016.

Preparation Of Interim Financial Statements (Policy)

6 Months Ended

Jun. 30, 2016

Basis of Presentation and Significant Accounting Policies

Basis of Presentation Throughout this document, AT&T Inc. is referred to as “AT&T,” “we” or the “Company.” These consolidated financial statements include all adjustments that are necessary to present fairly the results for the presented interim periods, consisting of normal recurring accruals and other items. The results for the interim periods are not necessarily indicative of those for the full year. You should read this document in conjunction with the consolidated financial statements and accompanying notes included in our Annual Report on Form 10-K for the year ended December 31, 2015.

The consolidated financial statements include the accounts of the Company and our majority-owned subsidiaries and affiliates, including the results of DIRECTV and wireless properties in Mexico for the period from acquisition to the reporting date. Our subsidiaries and affiliates operate in the communications and digital entertainment services industry, providing services and equipment that deliver voice, video and broadband services domestically and internationally.

All significant intercompany transactions are eliminated in the consolidation process. Investments in less than majority-owned subsidiaries and partnerships where we have significant influence are accounted for under the equity method. Earnings from certain investments accounted for using the equity method are included for periods ended within up to one quarter of our period end. We also record our proportionate share of our equity method investees' other comprehensive income (OCI) items, including cumulative translation adjustments.

The preparation of financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes, including estimates of probable losses and expenses. Actual results could differ from those estimates. Certain prior period amounts have been conformed to the current period's presentation, including our 2015 change in accounting to capitalize customer set-up and installation costs and amortize them over the expected economic life of the customer relationship. The consolidated statements of income also include revisions to present “Equipment” and “Broadcast, programming and operations” costs separately from “Other cost of services.”

Leases

Leases In February 2016, the Financial Accounting Standards Board (FASB) issued ASU No. 2016-02, “Leases (Topic 842)” (ASU 2016-02), which replaces existing leasing rules with a comprehensive lease measurement and recognition standard and expanded disclosure requirements. ASU 2016-02 will require lessees to recognize most leases on their balance sheets as liabilities, with corresponding “right-of-use” assets. Leases will be classified as either a finance or an operating lease without relying upon the bright-line tests under current GAAP.

Upon initial evaluation, we believe the key change upon adoption will be the balance sheet recognition. The income statement recognition appears similar to our current methodology.

ASU 2016-02 becomes effective for annual reporting periods beginning after December 15, 2018, subject to early adoption. We have just begun our evaluation of the impact on our financial statements, as well as available adoption methods, but we believe our implementation of the revenue recognition standard discussed below could influence the timing of our adoption of ASU 2016-02.

Revenue Recognition

Revenue Recognition In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (ASU 2014-09) and has since modified the standard four times. These standards replace existing revenue recognition rules with a comprehensive revenue measurement and recognition standard and expanded disclosure requirements. ASU 2014-09, as amended, becomes effective for annual reporting periods beginning after December 15, 2017, at which point we plan to adopt the standard.

The FASB allows two adoption methods under ASU 2014-09. Under one method, a company will apply the rules to contracts in all reporting periods presented, subject to certain allowable exceptions. Under the other method, a company will apply the rules to all contracts existing as of January 1, 2018, recognizing in beginning retained earnings an adjustment for the cumulative effect of the change and providing additional disclosures comparing results to previous rules (“modified retrospective method”). We continue to evaluate the available adoption methods.

Upon initial evaluation, we believe the key changes in the standard that impact our revenue recognition relate to the allocation of contract revenues between various services and equipment, and the timing of when those revenues are recognized. We are still in the process of evaluating these impacts. As a result of our accounting policy change for customer set-up and installation costs in 2015, we believe under the new standard that the requirement to defer such costs will not result in a significant change to our results. However, the requirement to defer incremental contract acquisition costs and recognize them over the contract period or expected customer life will result in the recognition of a deferred charge on our balance sheets. We cannot currently estimate the impact of this change upon adoption, as the industry continues to undergo changes in how devices and services are sold to customers.

Customer Fulfillment Costs

Customer Fulfillment Costs During the second quarter of 2016, we updated our analysis of the economic lives of customer relationships, which included a review of satellite customer data following the DIRECTV acquisition. As of April 1, 2016, to better reflect the estimated economic lives of satellite and certain business customer relationships, we extended the period to approximately 4.5 years. This change in accounting estimate decreased other cost of services and impacted net income $82, or $0.01 per diluted share, in the second quarter of 2016.

- Definition

Disclosure of accounting policy for leasing arrangements (both lessor and lessee). This disclosure may address (1) lease classification (that is, operating versus capital), (2) how the term of a lease is determined (for example, the circumstances in which a renewal option is considered part of the lease term), (3) how rental revenue or expense is recognized for a lease that contains rent escalations, (4) an entity's accounting treatment for deferred rent, including that which arises from lease incentives, rent abatements, rent holidays, or tenant allowances (5) an entity's accounting treatment for contingent rental payments and (6) an entity's policy for reviewing, at least annually, the residual values of sales-type and direct-finance leases. The disclosure also may indicate how the entity accounts for its capital leases, leveraged leases or sale-leaseback transactions.

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- Definition

Disclosure of accounting policy for revenue recognition. If the entity has different policies for different types of revenue transactions, the policy for each material type of transaction is generally disclosed. If a sales transaction has multiple element arrangements (for example, delivery of multiple products, services or the rights to use assets) the disclosure may indicate the accounting policy for each unit of accounting as well as how units of accounting are determined and valued. The disclosure may encompass important judgment as to appropriateness of principles related to recognition of revenue. The disclosure also may indicate the entity's treatment of any unearned or deferred revenue that arises from the transaction.

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