Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 4,348	$ 4,759
Foreign currency:
Translation adjustment (includes $0 and $2 attributable to noncontrolling interest), net of taxes of $49 and $175	288	108
Securities:
Net unrealized gains, net of taxes of $5 and $(4)	16	(12)
Derivative instruments:
Net unrealized gains (losses), net of taxes of $34 and $180	127	674
Reclassification adjustment included in net income, net of taxes of $2 and $3	11	12
Defined benefit postretirement plans:
Net prior service (cost) credit arising during period, net of taxes of $0 and $185	0	567
Amortization of net prior service credit included in net income, net of taxes of $(113) and $(105)	(346)	(323)
Other comprehensive income (loss)	96	1,026
Total comprehensive income	4,444	5,785
Less: Total comprehensive income attributable to noncontrolling interest	(252)	(99)
Total Comprehensive Income Attributable to AT&T	$ 4,192	$ 5,686