Segment Reporting (Capital Expenditures of Reportable Segments) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	$ 698.6	$ 983.6
Assets acquired under capital-related vendor financing arrangements	(508.9)	(635.9)
Assets acquired under capital leases	(12.2)	(23.9)
Changes in current liabilities related to capital expenditures	153.8	160.4
Third-party payments	371.6	509.6
Proceeds received for transfers to related parties	(40.3)	(25.4)
Total capital expenditures, net	331.3	484.2
U.K./Ireland
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	395.3	559.2
Belgium
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	141.7	185.2
Switzerland
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	58.6	52.8
Central and Eastern Europe
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	21.7	37.9
Central and Corporate
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	81.3	148.5
VodafoneZiggo JV
Segment Reporting Information [Line Items]
Property and equipment additions - VodafoneZiggo JV	$ 192.1	$ 239.8