Segment Reporting (Revenue by Major Category) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Principal Transaction Revenue [Line Items]
Total	$ 1,269.1	$ 1,057.9	$ 2,440.3	$ 2,149.2
Total residential fixed revenue
Principal Transaction Revenue [Line Items]
Total	443.8	419.3	855.7	842.8
Total subscription revenue
Principal Transaction Revenue [Line Items]
Total	439.2	416.0	846.0	836.1
Broadband internet
Principal Transaction Revenue [Line Items]
Total	238.3	219.0	456.7	438.5
Video
Principal Transaction Revenue [Line Items]
Total	153.7	148.0	297.8	297.9
Fixed-line telephony
Principal Transaction Revenue [Line Items]
Total	47.2	49.0	91.5	99.7
Non-subscription revenue
Principal Transaction Revenue [Line Items]
Total	4.6	3.3	9.7	6.7
Total residential revenue
Principal Transaction Revenue [Line Items]
Total	606.4	582.9	1,170.2	1,174.5
Total residential mobile revenue
Principal Transaction Revenue [Line Items]
Total	162.6	163.6	314.5	331.7
Subscription revenue
Principal Transaction Revenue [Line Items]
Total	125.0	121.0	240.7	242.7
Non-subscription revenue
Principal Transaction Revenue [Line Items]
Total	37.6	42.6	73.8	89.0
Total B2B revenue
Principal Transaction Revenue [Line Items]
Total	225.9	211.6	432.9	418.9
Subscription revenue
Principal Transaction Revenue [Line Items]
Total	112.5	107.2	216.3	214.2
Non-subscription revenue
Principal Transaction Revenue [Line Items]
Total	113.4	104.4	216.6	204.7
Other revenue
Principal Transaction Revenue [Line Items]
Total	$ 436.8	$ 263.4	$ 837.2	$ 555.8