Segment Reporting (Capital Expenditures of Reportable Segments) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	$ 1,381.3	$ 1,846.4
Assets acquired under capital-related vendor financing arrangements	(926.3)	(1,186.7)
Assets acquired under capital leases	(32.6)	(46.5)
Changes in current liabilities related to capital expenditures	210.5	181.6
Third-party payments	691.2	852.1
Proceeds received for transfers to related parties	(58.3)	(57.3)
Total capital expenditures, net	632.9	794.8
U.K./Ireland
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	766.7	1,040.1
Belgium
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	279.3	355.2
Switzerland
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	135.9	105.2
Central and Eastern Europe
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	41.4	67.9
Central and Corporate
Segment Reporting Information [Line Items]
Total consolidated property and equipment additions	158.0	278.0
VodafoneZiggo JV
Segment Reporting Information [Line Items]
Property and equipment additions - VodafoneZiggo JV	$ 426.5	$ 476.6