v3.20.4

Debt (Summary Of Long-Term Debt Of AT&T And Its Subsidiaries) (Details) - USD ($) $ in Millions | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Debt Instrument [Line Items] |  |
Carrying amount of notes and debentures | $ 165,451 | $ 164,557
Unamortized (discount) premium - net | (9,710) | (2,996)
Unamortized issuance costs | (532) | (452)
Total notes and debentures | 155,209 | 161,109
Finance lease obligations | 2,036 | 2,034
Total long-term debt, including current maturities | 157,245 | 163,143
Current maturities of long-term debt | (3,470) | (11,834)
Total long-term debt | 153,775 | 151,309
Credit agreement borrowings |  |
Debt Instrument [Line Items] |  |
Carrying amount of notes and debentures | 300 | 4,969
Fair value of interest rate swaps recorded in debt |  |
Debt Instrument [Line Items] |  |
Carrying amount of notes and debentures | 20 | 26
Notes And Debentures Maturing 2020-2039 | Notes and debentures |  |
Debt Instrument [Line Items] |  |
Carrying amount of notes and debentures | $ 25,549 | 17,404
Notes And Debentures Maturing 2020-2039 | Notes and debentures | Minimum |  |
Debt Instrument [Line Items] |  |
Debt instrument - stated percentage rate | 0.98% |
Notes And Debentures Maturing 2020-2039 | Notes and debentures | Maximum |  |
Debt Instrument [Line Items] |  |
Debt instrument - stated percentage rate | 2.99% |
Notes And Debentures Maturing 2020-2050 | Notes and debentures |  |
Debt Instrument [Line Items] |  |
Carrying amount of notes and debentures | $ 110,317 | 102,595
Notes And Debentures Maturing 2020-2050 | Notes and debentures | Minimum |  |
Debt Instrument [Line Items] |  |
Debt instrument - stated percentage rate | 3.00% |
Notes And Debentures Maturing 2020-2050 | Notes and debentures | Maximum |  |
Debt Instrument [Line Items] |  |
Debt instrument - stated percentage rate | 4.99% |
Notes And Debentures Maturing 2020-2095 | Notes and debentures |  |
Debt Instrument [Line Items] |  |
Carrying amount of notes and debentures | $ 24,259 | 34,513
Notes And Debentures Maturing 2020-2095 | Notes and debentures | Minimum |  |
Debt Instrument [Line Items] |  |
Debt instrument - stated percentage rate | 5.00% |
Notes And Debentures Maturing 2020-2095 | Notes and debentures | Maximum |  |
Debt Instrument [Line Items] |  |
Debt instrument - stated percentage rate | 6.99% |
Notes And Debentures Maturing 2020-2097 | Notes and debentures |  |
Debt Instrument [Line Items] |  |
Carrying amount of notes and debentures | $ 5,006 | $ 5,050
Notes And Debentures Maturing 2020-2097 | Notes and debentures | Minimum |  |
Debt Instrument [Line Items] |  |
Debt instrument - stated percentage rate | 7.00% |
Notes And Debentures Maturing 2020-2097 | Notes and debentures | Maximum |  |
Debt Instrument [Line Items] |  |
Debt instrument - stated percentage rate | 9.15% |

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