v3.20.4

Goodwill And Other Intangible Assets (Summary Of Changes In Carrying Amount Of Goodwill, By Segment) (Details) $ in Millions |  | 1 Months Ended | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | ---
Dec. 31, 2020 USD ($) reporting_unit | Dec. 31, 2020 USD ($) | Jun. 30, 2020 USD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Oct. 01, 2020
Goodwill [Line Items] |  |  |  |  |  |
Goodwill impairment |  |  |  | $ 10,465 |  |
Goodwill [Roll Forward] |  |  |  |  |  |
Beginning balance |  |  |  | 146,241 | $ 146,370 |
Acquisitions |  |  |  | 415 | 66 |
Impairments |  |  |  | (10,465) |  |
Dispositions, currency exchange and other |  |  |  | (932) | (195) |
Ending balance | $ 135,259 | $ 135,259 |  | 135,259 | 146,241 |
Orbital slots |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |
Impairment charge - intangible assets |  | 4,373 |  |  |  |
Customer lists |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |
Impairment charge - intangible assets |  | 1,201 |  |  |  |
Communications |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |
Goodwill impairment |  |  |  | 8,253 |  |
Number of reporting units | reporting_unit | 4 |  |  |  |  |
Goodwill [Roll Forward] |  |  |  |  |  |
Beginning balance |  |  |  | 100,234 | 100,551 |
Acquisitions |  |  |  | 0 | 0 |
Impairments |  |  |  | (8,253) |  |
Dispositions, currency exchange and other |  |  |  | (5) | (317) |
Ending balance | $ 91,976 | 91,976 |  | 91,976 | 100,234 |
Communications | Entertainment Group |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |
Percent fair values exceeded book values (less than) |  |  |  |  |  | 10.00%
Communications | Video |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |
Long-lived asset impairment |  | 7,255 |  |  |  |
Goodwill impairment |  | 8,253 |  |  |  |
Goodwill [Roll Forward] |  |  |  |  |  |
Impairments |  | (8,253) |  |  |  |
Communications | Broadband |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |
Goodwill impairment |  | 0 |  |  |  |
Goodwill [Roll Forward] |  |  |  |  |  |
Impairments |  | 0 |  |  |  |
WarnerMedia |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |
Goodwill impairment |  |  |  | 0 |  |
Number of reporting units | reporting_unit | 4 |  |  |  |  |
Goodwill [Roll Forward] |  |  |  |  |  |
Beginning balance |  |  |  | 42,345 | 42,101 |
Acquisitions |  |  |  | 415 | 66 |
Impairments |  |  |  | 0 |  |
Dispositions, currency exchange and other |  |  |  | (313) | 178 |
Ending balance | $ 42,447 | 42,447 |  | 42,447 | 42,345 |
WarnerMedia | Turner |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |
Percent fair values exceeded book values (less than) |  |  |  |  |  | 10.00%
WarnerMedia | Home Box Office |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |
Percent fair values exceeded book values (less than) |  |  |  |  |  | 10.00%
Latin America |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |
Goodwill impairment |  |  |  | 2,212 |  |
Number of reporting units | reporting_unit | 2 |  |  |  |  |
Goodwill [Roll Forward] |  |  |  |  |  |
Beginning balance |  |  |  | 3,662 | 3,718 |
Acquisitions |  |  |  | 0 | 0 |
Impairments |  |  |  | (2,212) |  |
Dispositions, currency exchange and other |  |  |  | (614) | (56) |
Ending balance | $ 836 | $ 836 |  | $ 836 | $ 3,662 |
Latin America | Vrio | Latin America |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |
Goodwill impairment |  |  | $ 2,212 |  |  |
Goodwill [Roll Forward] |  |  |  |  |  |
Impairments |  |  | (2,212) |  |  |
Latin America | Vrio | Latin America | Noncontrolling Interest |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |
Goodwill impairment |  |  | 105 |  |  |
Goodwill [Roll Forward] |  |  |  |  |  |
Impairments |  |  | $ (105) |  |  |

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