Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 3,168	$ 3,949	$ 9,694	$ 12,271
Foreign currency:
Translation adjustment (includes $(2), $(17), $(61) and $(15) attributable to noncontrolling interest), net of taxes of $47, $(69), $(150) and $(21)	90	(342)	(1,459)	(181)
Securities:
Net unrealized gains (losses), net of taxes of $1, $7, $28 and $22	1	25	81	67
Derivative instruments:
Net unrealized gains (losses), net of taxes of $229, $(168), $(574) and $(299)	860	(516)	(2,166)	(1,006)
Reclassification adjustment included in net income, net of taxes of $7, $2, $11 and $7	27	7	44	24
Defined benefit postretirement plans:
Amortization of net prior service credit included in net income, net of taxes of $(150), $(112), $(451) and $(332)	(460)	(343)	(1,382)	(1,031)
Other comprehensive income (loss)	518	(1,169)	(4,882)	(2,127)
Total comprehensive income	3,686	2,780	4,812	10,144
Less: Total comprehensive income attributable to noncontrolling interest	(350)	(232)	(926)	(747)
Total Comprehensive Income Attributable to AT&T	$ 3,336	$ 2,548	$ 3,886	$ 9,397