Acquisitions, Dispositions and Other Adjustments (Pro Forma) (Details) - Time Warner Inc. [Member] - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Business Acquisition Pro Forma Information [Line Items]
Total operating revenue	$ 135,658	$ 139,236
Net Income Attributable to AT&T	$ 16,254	$ 11,576
Basic Earnings Per Share Attributable to AT&T	$ 2.23	$ 1.59
Diluted Earnings Per Share Attributable to AT&T	$ 2.22	$ 1.57

The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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