Segment Reporting (Balance Sheet Data of Reportable Segments) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Long-lived assets	$ 28,470.7	$ 28,629.0
Total assets	49,046.3	53,153.6
VodafoneZiggo JV
Segment Reporting Information [Line Items]
Long-lived assets	20,674.8	22,026.2
Total assets	22,426.5	23,255.3
Operating Segments \| U.K./Ireland
Segment Reporting Information [Line Items]
Long-lived assets	16,170.9	16,254.6
Total assets	20,665.5	20,702.5
Operating Segments \| Belgium
Segment Reporting Information [Line Items]
Long-lived assets	5,910.3	5,979.4
Total assets	7,148.2	6,972.1
Operating Segments \| Switzerland
Segment Reporting Information [Line Items]
Long-lived assets	4,247.7	4,165.4
Total assets	4,647.8	4,496.0
Operating Segments \| Central and Eastern Europe
Segment Reporting Information [Line Items]
Long-lived assets	1,062.2	1,087.4
Total assets	1,135.2	1,130.8
Central and Corporate
Segment Reporting Information [Line Items]
Long-lived assets	1,079.6	1,142.2
Total assets	15,449.6	9,321.1
Total - continuing operations
Segment Reporting Information [Line Items]
Long-lived assets	28,470.7	28,629.0
Total assets	$ 49,046.3	$ 42,622.5

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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