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Basis of Presentation, Narrative (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2018 | Mar. 31, 2017
Basis of Presentation [Line Items] |  |
Amounts recorded gross in revenues that are billed to customers and remitted to governmental authorities | $ 17 | $ 14
TDS |  |
Basis of Presentation [Line Items] |  |
TDS ownership of U.S. Cellular | 83.00% |

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