Segment Reporting (Performance Measures) (Schedule) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Revenue	$ 1,854.5	$ 1,746.3	$ 5,570.9	$ 5,353.8
Adjusted EBITDA	597.7	664.0	1,823.6	1,998.1
VMO2 JV
Segment Reporting Information [Line Items]
Revenue	3,503.8	3,042.1	10,058.0	9,642.7
VMO2 JV | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Segment Reporting Information [Line Items]
Adjusted EBITDA	1,170.9	1,060.5	3,335.6	3,515.2
VodafoneZiggo JV
Segment Reporting Information [Line Items]
Revenue	1,125.2	1,041.7	3,297.0	3,237.3
VodafoneZiggo JV | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Segment Reporting Information [Line Items]
Adjusted EBITDA	518.3	501.4	1,474.7	1,530.1
Operating Segments | Switzerland
Segment Reporting Information [Line Items]
Revenue	859.3	789.8	2,482.9	2,377.3
Adjusted EBITDA	311.0	292.8	861.1	850.3
Operating Segments | Belgium
Segment Reporting Information [Line Items]
Revenue	775.2	665.1	2,296.7	2,078.6
Adjusted EBITDA	339.8	316.6	988.7	982.9
Operating Segments | Ireland
Segment Reporting Information [Line Items]
Revenue	125.5	116.1	372.4	365.4
Adjusted EBITDA	45.9	46.3	134.7	141.9
Central and Other
Segment Reporting Information [Line Items]
Revenue	164.3	238.3	615.0	720.2
Adjusted EBITDA	(83.6)	22.4	(115.3)	68.5
Intersegment eliminations
Segment Reporting Information [Line Items]
Revenue	(69.8)	(63.0)	(196.1)	(187.7)
Adjusted EBITDA	$ (15.4)	$ (14.1)	$ (45.6)	$ (45.5)