Segment Reporting (Capital Expenditures of Reportable Segments) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	$ 654.4	$ 698.6
Assets acquired under capital-related vendor financing arrangements	(370.9)	(508.9)
Assets acquired under capital leases	(11.1)	(12.2)
Changes in current liabilities related to capital expenditures	75.4	153.8
Third-party payments	348.3	371.6
Proceeds received for transfers to related parties	(0.5)	(40.3)
Total capital expenditures, net	347.8	331.3
VodafoneZiggo JV
Segment Reporting Information [Line Items]
Property and equipment additions - VodafoneZiggo JV	245.4	192.1
Operating Segments | U.K./Ireland
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	346.6	395.3
Operating Segments | Belgium
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	141.6	141.7
Operating Segments | Switzerland
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	69.2	58.6
Operating Segments | Central and Eastern Europe
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	18.9	21.7
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	$ 78.1	$ 81.3