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%

X

- Definition

[Line Items] for Basis of Presentation [Table]

+ References

No definition available.

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- Definition

Number of Markets

+ References

No definition available.

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

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- Definition

The number of countries in which the entity operates as of balance sheet date.

+ References

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- Definition

Percentage of subsidiary's or equity method investee's stock owned by parent immediately after all stock transactions.

+ References

No definition available.

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- Details

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- Details

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- Details

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