Segment Information (Summary Of Operating Revenues And Expenses By Segment) (Narrative) (Details) $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments	4
Amortization of production costs	$ 9,587	$ 3,772	$ 0
WarnerMedia [Member] \| Pre-Acquisition Released Programming Costs [Member]
Segment Reporting Information [Line Items]
Amortization of production costs	$ 472	$ 1,416

Noncash amortization of film and television costs which represent the direct production costs and production overhead relating to producing theatrical feature films and television product that are sold, licensed and distributed through the primary and secondary market windows; participation and residual costs to financial participants as well as costs relating to network programming (e.g., rights to exhibit feature films, television series and movies, and other programming).

No definition available.

Name:	t_AmortizationOfFilmAndTelevisionCosts
Namespace Prefix:	t_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration