Segment Reporting (Revenue by Major Category) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Principal Transaction Revenue [Line Items]
Total	$ 1,171.2	$ 1,091.3
Total residential fixed revenue
Principal Transaction Revenue [Line Items]
Total	411.9	423.5
Total subscription revenue
Principal Transaction Revenue [Line Items]
Total	406.8	420.1
Broadband internet
Principal Transaction Revenue [Line Items]
Total	218.4	219.5
Video
Principal Transaction Revenue [Line Items]
Total	144.1	149.9
Fixed-line telephony
Principal Transaction Revenue [Line Items]
Total	44.3	50.7
Non-subscription revenue
Principal Transaction Revenue [Line Items]
Total	5.1	3.4
Total residential revenue
Principal Transaction Revenue [Line Items]
Total	563.8	591.6
Total residential mobile revenue
Principal Transaction Revenue [Line Items]
Total	151.9	168.1
Subscription revenue
Principal Transaction Revenue [Line Items]
Total	115.7	121.7
Non-subscription revenue
Principal Transaction Revenue [Line Items]
Total	36.2	46.4
Total B2B revenue
Principal Transaction Revenue [Line Items]
Total	207.0	207.3
Subscription revenue
Principal Transaction Revenue [Line Items]
Total	103.8	107.0
Non-subscription revenue
Principal Transaction Revenue [Line Items]
Total	103.2	100.3
Other revenue
Principal Transaction Revenue [Line Items]
Total	$ 400.4	$ 292.4