v3.20.4
Segment Information (Reconciliation Of Operating Income (Loss) to Consolidated Statement Of Income) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]      
Income (Loss) Before Income Taxes $ (2,856) $ 18,468 $ 24,873
AT&T Operating Income 6,405 27,955 26,096
Amortization of intangibles acquired (8,239) (7,932) (8,347)
Impairments and abandonments (18,880) (1,458) (46)
Equity in net income (loss) of affiliates 95 6 (48)
Interest Expense 7,925 8,422 7,957
Other income (expense) - net (1,431) (1,071) 6,782
Operating Segments      
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]      
Income (Loss) Before Income Taxes 38,002 42,254 38,418
AT&T Operating Income 37,960 42,066 38,359
Equity in net income (loss) of affiliates 42 188 59
Operating Segments | Communications      
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]      
Income (Loss) Before Income Taxes 30,521 32,230 32,108
AT&T Operating Income 30,521 32,230 32,108
Equity in net income (loss) of affiliates 0 0 0
Operating Segments | WarnerMedia      
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]      
Income (Loss) Before Income Taxes 8,210 10,659 7,020
AT&T Operating Income 8,192 10,498 6,995
Equity in net income (loss) of affiliates 18 161 25
Operating Segments | Latin America      
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]      
Income (Loss) Before Income Taxes (729) (635) (710)
AT&T Operating Income (753) (662) (744)
Equity in net income (loss) of affiliates 24 27 34
Corporate and Other      
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]      
AT&T Operating Income (2,342) (1,978) (1,722)
Reconciling Items      
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]      
Merger and integration items (468) (1,032) (1,234)
Amortization of intangibles acquired (8,012) (7,460) (6,931)
Impairments and abandonments (18,880) (1,458) (46)
Gain on spectrum transaction 900 0 0
Employee separation charges and benefit-related (gain) loss (1,177) (624) (587)
Other noncash charges (credits), net (13) (43) (111)
Natural disaster items 0 0 (181)
Equity in net income (loss) of affiliates (42) (188) (59)
Eliminations and consolidations      
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]      
AT&T Operating Income $ (1,563) $ (1,516) $ (1,451)