Segment Reporting (Capital Expenditures of Reportable Segments) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	$ 1,242.4	$ 1,381.3
Assets acquired under capital-related vendor financing arrangements	(702.9)	(926.3)
Assets acquired under finance leases	(17.2)	(32.6)
Changes in current liabilities related to capital expenditures	127.3	210.5
Third-party payments	650.9	691.2
Proceeds received for transfers to related parties	(1.3)	(58.3)
Total capital expenditures, net	649.6	632.9
VodafoneZiggo JV
Segment Reporting Information [Line Items]
Property and equipment additions - VodafoneZiggo JV	472.4	426.5
Operating Segments | U.K./Ireland
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	669.4	766.7
Operating Segments | Belgium
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	251.9	275.1
Operating Segments | Switzerland
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	123.8	135.9
Operating Segments | Central and Eastern Europe
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	39.8	41.4
Central and Corporate
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	$ 157.5	$ 162.2