Segment Information (Reconciliation Of Operating Income (Loss) to Consolidated Statement Of Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations Before Income Taxes	$ 16,698	$ 19,848	$ (3,094)
AT&T Operating Income (Loss)	19,049	23,461	(4,587)
Asset impairments and abandonments and restructuring	(5,075)	(1,193)	(27,498)
Interest expense	6,759	6,704	6,108
Equity in net income of affiliates	1,989	1,675	1,791
Other income (expense) – net	2,419	1,416	5,810
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations Before Income Taxes	27,135	27,660	26,410
AT&T Operating Income (Loss)	27,135	27,660	26,410
Operating Segments | Communications
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations Before Income Taxes	27,095	27,801	26,736
AT&T Operating Income (Loss)	27,095	27,801	26,736
Operating Segments | Latin America Business Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations Before Income Taxes	40	(141)	(326)
AT&T Operating Income (Loss)	40	(141)	(326)
Corporate
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
AT&T Operating Income (Loss)	(2,902)	(2,961)	(2,890)
Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Transaction and other costs	(123)	(98)	(425)
Amortization of intangibles acquired	(53)	(76)	(76)
Asset impairments and abandonments and restructuring	(5,075)	(1,193)	(27,498)
Benefit-related gains (losses)	$ 67	$ 129	$ (108)