v3.19.3.a.u2
Debt (Summary Of Long-Term Debt Of AT&T And Its Subsidiaries) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Debt Instrument [Line Items]    
Unamortized (discount) premium - net $ (2,996) $ (2,526)
Unamortized issuance costs (452) (466)
Total notes and debentures 161,109 171,529
Finance lease obligations 2,034 1,911
Total long-term debt and capital lease obligations 163,143 173,440
Current maturities of long-term debt (11,834) (7,190)
Total long-term debt 151,309 166,250
Notes And Debentures [Member]    
Debt Instrument [Line Items]    
Total notes and debentures $ 164,557 $ 174,521
Notes And Debentures Maturing 2019-2039 [Member] | Notes And Debentures [Member]    
Debt Instrument [Line Items]    
Debt instrument, maturity date range, start Dec. 31, 2019 Dec. 31, 2019
Debt instrument, maturity date range, end Dec. 31, 2039 Dec. 31, 2039
Total notes and debentures [1] $ 17,404 $ 14,404
Notes And Debentures Maturing 2019-2039 [Member] | Notes And Debentures [Member] | Minimum [Member]    
Debt Instrument [Line Items]    
Debt instument - stated percentage rate 1.80% 1.80%
Notes And Debentures Maturing 2019-2039 [Member] | Notes And Debentures [Member] | Maximum [Member]    
Debt Instrument [Line Items]    
Debt instument - stated percentage rate 2.99% 2.99%
Notes And Debentures Maturing 2019-2050 [Member] | Notes And Debentures [Member]    
Debt Instrument [Line Items]    
Debt instrument, maturity date range, start Dec. 31, 2019 Dec. 31, 2019
Debt instrument, maturity date range, end Dec. 31, 2050 Dec. 31, 2050
Total notes and debentures [1] $ 102,595 $ 104,291
Notes And Debentures Maturing 2019-2050 [Member] | Notes And Debentures [Member] | Minimum [Member]    
Debt Instrument [Line Items]    
Debt instument - stated percentage rate 3.00% 3.00%
Notes And Debentures Maturing 2019-2050 [Member] | Notes And Debentures [Member] | Maximum [Member]    
Debt Instrument [Line Items]    
Debt instument - stated percentage rate 4.99% 4.99%
Notes And Debentures Maturing 2019-2095 [Member] | Notes And Debentures [Member]    
Debt Instrument [Line Items]    
Debt instrument, maturity date range, start Dec. 31, 2019 Dec. 31, 2019
Debt instrument, maturity date range, end Dec. 31, 2095 Dec. 31, 2095
Total notes and debentures [1] $ 34,513 $ 37,175
Notes And Debentures Maturing 2019-2095 [Member] | Notes And Debentures [Member] | Minimum [Member]    
Debt Instrument [Line Items]    
Debt instument - stated percentage rate 5.00% 5.00%
Notes And Debentures Maturing 2019-2095 [Member] | Notes And Debentures [Member] | Maximum [Member]    
Debt Instrument [Line Items]    
Debt instument - stated percentage rate 6.99% 6.99%
Notes And Debentures Maturing 2019-2097 [Member] | Notes And Debentures [Member]    
Debt Instrument [Line Items]    
Debt instrument, maturity date range, start Dec. 31, 2019 Dec. 31, 2019
Debt instrument, maturity date range, end Dec. 31, 2097 Dec. 31, 2097
Total notes and debentures [1] $ 5,050 $ 5,976
Notes And Debentures Maturing 2019-2097 [Member] | Notes And Debentures [Member] | Minimum [Member]    
Debt Instrument [Line Items]    
Debt instument - stated percentage rate 7.00% 7.00%
Notes And Debentures Maturing 2019-2097 [Member] | Notes And Debentures [Member] | Maximum [Member]    
Debt Instrument [Line Items]    
Debt instument - stated percentage rate 9.15% 9.15%
Credit agreement borrowings [Member] | Notes And Debentures [Member]    
Debt Instrument [Line Items]    
Total notes and debentures $ 4,969 $ 12,618
Other Debt [Member] | Notes And Debentures [Member]    
Debt Instrument [Line Items]    
Total notes and debentures 0 89
Fair value of interest rate swaps recorded in debt [Member] | Notes And Debentures [Member]    
Debt Instrument [Line Items]    
Total notes and debentures $ 26 $ (32)
[1] Maturities assume putable debt is redeemed by the holders at the next opportunity.