v3.20.4
Consolidated Statements of Comprehensive Income - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Statement of Comprehensive Income [Abstract]      
Net income (loss) $ (3,821) $ 14,975 $ 19,953
Foreign Currency:      
Translation adjustment (includes $(59), $(9) and $(32) attributable to noncontrolling interest), net of taxes of $(42), $18 and $(45) (929) 19 (1,062)
Securities:      
Net unrealized gains (losses), net of taxes of $27, $17 and $(1) 78 50 (4)
Reclassification adjustment included in net income, net of taxes of $(5), $0 and $0 (15) 0 0
Derivative Instruments:      
Net unrealized gains (losses), net of taxes of $(212), $(240) and $(156) (811) (900)  
Net unrealized gains (losses), net of taxes of $(212), $(240) and $(156)     (597)
Reclassification adjustment included in net income, net of taxes of $18, $12 and $6 69 45  
Reclassification adjustment included in net income, net of taxes of $18, $12 and $6     13
Defined benefit postretirement plans:      
Net prior service credit arising during period, net of taxes of $735, $1,134 and $271 2,250 3,457 830
Amortization of net prior service credit included in net income, net of taxes of $(601), $(475) and $(431) (1,841) (1,459) (1,322)
Other comprehensive income (loss) (1,199) 1,212 (2,142)
Total comprehensive income (loss) (5,020) 16,187 17,811
Less: Total comprehensive income attributable to noncontrolling interest (1,296) (1,063) (551)
Total Comprehensive Income (Loss) Attributable to AT&T $ (6,316) $ 15,124 $ 17,260