Segment Reporting (Capital Expenditures of Reportable Segments) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Total property and equipment additions	$ 1,107.7	$ 1,089.6
Assets acquired under capital-related vendor financing arrangements	(129.9)	(142.9)
Assets acquired under finance leases	(20.8)	(25.8)
Changes in current liabilities related to capital expenditures	59.2	8.4
Total capital expenditures, net	1,016.2	929.3
VMO2 JV
Segment Reporting Information [Line Items]
Property and equipment additions:	1,949.1	2,053.7
VodafoneZiggo JV
Segment Reporting Information [Line Items]
Property and equipment additions:	737.8	683.7
Operating Segments | Switzerland
Segment Reporting Information [Line Items]
Total property and equipment additions	406.8	412.5
Operating Segments | Belgium
Segment Reporting Information [Line Items]
Total property and equipment additions	512.1	454.3
Operating Segments | Ireland
Segment Reporting Information [Line Items]
Total property and equipment additions	128.0	91.0
Central and Other
Segment Reporting Information [Line Items]
Total property and equipment additions	106.4	176.5
Intersegment eliminations
Segment Reporting Information [Line Items]
Total property and equipment additions	$ (45.6)	$ (44.7)