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Basis of Presentation - Narrative (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017
Basis of Presentation [Line Items] |  |  |  |
Amounts recorded gross in revenues that are billed to customers and remitted to governmental authorities | $ 16 | $ 14 | $ 50 | $ 42
TDS | U.S. Cellular |  |  |  |
Basis of Presentation [Line Items] |  |  |  |
Ownership percentage | 82.00% |  | 82.00% |

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- Details
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- Details
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