v3.10.0.1

Basis of Presentation (Narrative) (Details) | 6 Months Ended |  |
--- | --- | --- | ---
Jun. 30, 2018 market country | Dec. 31, 2017 | Dec. 31, 2016
Consumer and Business-to-Business Communication Services | Latin America and the Caribbean |  |  |
Basis of Presentation [Line Items] |  |  |
Number of countries in which entity provides services | country | 18 |  |
Sub-Sea Networks | Cable & Wireless Communications Limited (C&W) |  |  |
Basis of Presentation [Line Items] |  |  |
Number of markets | market | 40 |  |
Telenet |  |  |
Basis of Presentation [Line Items] |  |  |
Percentage ownership in subsidiary | 57.70% |  |
VodafoneZiggo JV |  |  |
Basis of Presentation [Line Items] |  |  |
Ownership percentage | 50.00% | 50.00% | 50.00%
Liberty Puerto Rico |  |  |
Basis of Presentation [Line Items] |  |  |
Ownership percentage | 60.00% |  |

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