v3.10.0.1

Segment Reporting (Geographic Segments) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 3,045.1	$ 2,774.9	$ 6,139.6	$ 5,444.7
VodafoneZiggo JV
Segment Reporting Information [Line Items]
Revenue	1,114.5	1,081.3	2,296.1	2,165.2
Operating Segments | U.K.
Segment Reporting Information [Line Items]
Revenue	1,605.6	1,454.8	3,250.0	2,855.2
Operating Segments | Belgium
Segment Reporting Information [Line Items]
Revenue	753.9	686.0	1,513.5	1,347.4
Operating Segments | Switzerland
Segment Reporting Information [Line Items]
Revenue	332.2	339.0	677.1	670.2
Operating Segments | Ireland
Segment Reporting Information [Line Items]
Revenue	129.3	111.3	263.1	215.3
Operating Segments | Poland
Segment Reporting Information [Line Items]
Revenue	110.4	101.8	226.4	197.7
Operating Segments | Slovakia
Segment Reporting Information [Line Items]
Revenue	15.8	14.6	32.3	28.9
Other, including intersegment eliminations (a)
Segment Reporting Information [Line Items]
Revenue	$ 97.9	$ 67.4	$ 177.2	$ 130.0

X

- Definition

The amount of revenue from sale of goods and services reduced by sales returns, allowances, and discounts reported by an equity method investment of the entity.

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