Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Net Income (Loss) Attributable to Parent [Abstract]
Net income (loss)	$ 12,253	$ 15,623	$ (7,055)
Foreign Currency:
Translation adjustment, net of taxes of $(175), $143 and $90	(545)	463	346
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	127	0	0
Securities:
Net unrealized gains (losses), net of taxes of $(5), $8 and $(49)	(19)	22	(143)
Reclassification adjustment included in net income (loss), net of taxes of $10, $4 and $3	30	11	8
Derivative Instruments:
Net unrealized gains (losses), net of taxes of $121, $228 and $(183)	380	922	(648)
Reclassification adjustment included in net income (loss), net of taxes of $14, $12 and $25	45	47	96
Defined benefit postretirement plans:
Net prior service (cost) credit arising during period, net of taxes of $0, $10 and $583	0	32	1,787
Amortization of net prior service credit included in net income (loss), net of taxes of $(492), $(642) and $(663)	(1,523)	(1,963)	(2,028)
Other comprehensive income (loss)	(1,505)	(466)	(763)
Total comprehensive income (loss)	10,748	15,157	(7,818)
Less: Total comprehensive income attributable to noncontrolling interest	(1,305)	(1,223)	(1,469)
Total Comprehensive Income (Loss) Attributable to AT&T	9,443	13,934	(9,287)
WarnerMedia
Foreign Currency:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	0	0	(182)
Derivative Instruments:
Distributions of WarnerMedia, net of taxes of $0, $0 and $(12)	0	0	(24)
Defined benefit postretirement plans:
Distributions of WarnerMedia, net of taxes of $0, $0 and $5	$ 0	$ 0	$ 25