Preparation Of Interim Financial Statements (Policy)	6 Months Ended
Jun. 30, 2020
Accounting Policies [Abstract]
Principles of Consolidation [Policy Text Block]	All significant intercompany transactions are eliminated in the consolidation process. Investments in subsidiaries and partnerships which we do not control but 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.
Basis of Accounting [Policy Text Block]	The preparation of financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions, including potential impacts arising from the COVID-19 pandemic, that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. Certain prior period amounts have been conformed to the current period’s presentation, including the combination of our prior Xandr segment with the WarnerMedia segment.
Credit Loss, Financial Instrument [Policy Text Block]	Credit Losses As of January 1, 2020, we adopted, through modified retrospective application, the Financial Accounting Standards Board’s (FASB) Accounting Standards Update (ASU) No. 2016-13, “Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (ASU 2016-13, as amended), which replaces the incurred loss impairment methodology under prior GAAP with an expected credit loss model. ASU 2016-13 affects trade receivables, loans, contract assets, certain beneficial interests, off-balance-sheet credit exposures not accounted for as insurance and other financial assets that are not subject to fair value through net income, as defined by the standard. Under the expected credit loss model, we are required to consider future economic trends to estimate expected credit losses over the lifetime of the asset. Upon adoption, we recorded a $293 reduction to “Retained earnings,” $395 increase to “allowances for doubtful accounts” applicable to our trade and loan receivables, $10 reduction of contract assets, $105 reduction of net deferred income tax liability and $7 reduction of “Noncontrolling interest” as an opening adjustment. Our adoption of ASU 2016-13 did not have a material impact on our financial statements.
Reference Rate Reform [Policy Text Block]	Reference Rate Reform In March 2020, the FASB issued ASU No. 2020-04, “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting” (ASU 2020-04), which provides optional expedients, and allows for certain exceptions to existing GAAP, for contract modifications triggered by the expected market transition of certain benchmark interest rates to alternative reference rates. ASU 2020-04 applies to contracts, hedging relationships and other arrangements that reference the London Interbank Offering Rate (LIBOR) or any other rates ending after December 31, 2022. We are evaluating the impact of our adoption of ASU 2020-04, including optional expedients, to our financial statements.
Spectrum Licenses [Policy Text Block]	During the first quarter of 2020, we reassessed and changed the estimated economic lives of certain trade names in our Latin America business from indefinite to finite-lived and began amortizing them using the straight-line method over their average remaining economic life of 15 years. This change had an insignificant impact on our financial statements. Also during the first quarter of 2020, in conjunction with the nationwide launch of AT&T TV and our customers’ continued shift from linear to streaming video services, we reassessed the estimated economic lives and renewal assumptions for our orbital slot licenses. As a result, we have changed the estimated lives of these licenses from indefinite to finite-lived, effective January 1, 2020, and began amortizing our orbital slot licenses using the sum-of-months-digits method over their average remaining economic life of 15 years. This change in accounting increased amortization expense $379, or $0.04 per diluted share available to common stock during the second quarter and $765, or $0.08, per diluted share available to common stock for the first six months of 2020.

Principles of Consolidation [Policy Text Block]

All significant intercompany transactions are eliminated in the consolidation process. Investments in subsidiaries and partnerships which we do not control but 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.

Credit Loss, Financial Instrument [Policy Text Block]

Credit Losses As of January 1, 2020, we adopted, through modified retrospective application, the Financial Accounting Standards Board’s (FASB) Accounting Standards Update (ASU) No. 2016-13, “Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (ASU 2016-13, as amended), which replaces the incurred loss impairment methodology under prior GAAP with an expected credit loss model. ASU 2016-13 affects trade receivables, loans, contract assets, certain beneficial interests, off-balance-sheet credit exposures not accounted for as insurance and other financial assets that are not subject to fair value through net income, as defined by the standard. Under the expected credit loss model, we are required to consider future economic trends to estimate expected credit losses over the lifetime of the asset. Upon adoption, we recorded a $293 reduction to “Retained earnings,” $395 increase to “allowances for doubtful accounts” applicable to our trade and loan receivables, $10 reduction of contract assets, $105 reduction of net deferred income tax liability and $7 reduction of “Noncontrolling interest” as an opening adjustment. Our adoption of ASU 2016-13 did not have a material impact on our financial statements.

Spectrum Licenses [Policy Text Block]

During the first quarter of 2020, we reassessed and changed the estimated economic lives of certain trade names in our Latin America business from indefinite to finite-lived and began amortizing them using the straight-line method over their average remaining economic life of 15 years. This change had an insignificant impact on our financial statements.

Also during the first quarter of 2020, in conjunction with the nationwide launch of AT&T TV and our customers’ continued shift from linear to streaming video services, we reassessed the estimated economic lives and renewal assumptions for our orbital slot licenses. As a result, we have changed the estimated lives of these licenses from indefinite to finite-lived, effective January 1, 2020, and began amortizing our orbital slot licenses using the sum-of-months-digits method over their average remaining economic life of 15 years. This change in accounting increased amortization expense $379, or $0.04 per diluted share available to common stock during the second quarter and $765, or $0.08, per diluted share available to common stock for the first six months of 2020.