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Preparation Of Interim Financial Statements (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jan. 01, 2020	Dec. 31, 2019
Change in Accounting Estimate [Line Items]
Diluted Earnings Per Share Attributable to Common Stock	$ 0.63	$ 0.56
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Retained earnings	$ 58,534			$ 57,936
Contract asset	2,598			2,472
Deferred income tax liabilities	58,491			59,502
Noncontrolling interest	$ 17,670			$ 17,713
DIRECTV [Member] \| Orbital Slots [Member] \| Intangible Assets, Amortization Period [Member]
Change in Accounting Estimate [Line Items]
Change in Accounting Estimate, Description	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.
Estimated economic useful life	15 years
Amortization expense	$ 386
Diluted Earnings Per Share Attributable to Common Stock	$ 0.04
Latin America [Member] \| Trade Names [Member] \| Intangible Assets, Amortization Period [Member]
Change in Accounting Estimate [Line Items]
Change in Accounting Estimate, Description	We also 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.
Estimated economic useful life	15 years
ASU 2016-13 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
ASU Adoption Date [CCYY-MM-DD format]			Jan. 01, 2020
ASU Early Adoption [true/false]			false
Transition Option Elected [Prospective/Retrospective/Modified Prospective/Modified Retrospective]			Modified Retrospective
Prior Period Not Restated [true/false]	true
Significant effect on the financial statements [Yes/No]	No
Retained earnings			$ (293)
Allowance for doubtful accounts			395
Contract asset			(10)
Deferred income tax liabilities			(105)
Noncontrolling interest			$ (7)