Long-lived Assets (Changes in Carrying Amount of Goodwill) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2025 USD ($)
Goodwill [Roll Forward]
Goodwill beginning balance	$ 3,152.6
Acquisitions and related adjustments	17.7
Foreign currency translation adjustments and other	140.6
Goodwill ending balance	3,310.9
Telenet
Goodwill [Roll Forward]
Goodwill beginning balance	2,656.4
Acquisitions and related adjustments	2.3
Foreign currency translation adjustments and other	118.8
Goodwill ending balance	2,777.5
VM Ireland
Goodwill [Roll Forward]
Goodwill beginning balance	250.8
Acquisitions and related adjustments	0.0
Foreign currency translation adjustments and other	11.2
Goodwill ending balance	262.0
Other
Goodwill [Roll Forward]
Goodwill beginning balance	245.4
Acquisitions and related adjustments	15.4
Foreign currency translation adjustments and other	10.6
Goodwill ending balance	$ 271.4