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Basis of Presentation - Narrative (Details) - USD ($) $ in Millions | Mar. 31, 2020 | Dec. 31, 2019
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ASC 326 |  |
Basis of Presentation [Line Items] |  |
Cumulative effect of change in retained earnings due to adoption of new accounting pronouncement |  | $ 0
ASU 2018-15 |  |
Basis of Presentation [Line Items] |  |
Cumulative effect of change in retained earnings due to adoption of new accounting pronouncement |  | $ 0
U.S. Cellular |  |
Basis of Presentation [Line Items] |  |
TDS ownership of U.S. Cellular | 83.00% |

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