Segment Reporting (Revenue by Major Category) (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
Total residential revenue
Segment Reporting Information [Line Items]
Revenue	1,292.9	1,184.0	3,758.3	3,627.1
Total residential mobile revenue
Segment Reporting Information [Line Items]
Revenue	521.2	483.3	1,507.7	1,444.6
Subscription revenue
Segment Reporting Information [Line Items]
Revenue	401.4	356.5	1,133.5	1,056.7
Non-subscription revenue
Segment Reporting Information [Line Items]
Revenue	119.8	126.8	374.2	387.9
Total residential fixed revenue
Segment Reporting Information [Line Items]
Revenue	771.7	700.7	2,250.6	2,182.5
Total subscription revenue
Segment Reporting Information [Line Items]
Revenue	753.4	689.0	2,206.8	2,145.8
Broadband internet
Segment Reporting Information [Line Items]
Revenue	385.6	336.1	1,111.0	1,037.5
Video
Segment Reporting Information [Line Items]
Revenue	276.6	261.3	822.5	817.2
Fixed-line telephony
Segment Reporting Information [Line Items]
Revenue	91.2	91.6	273.3	291.1
Non-subscription revenue
Segment Reporting Information [Line Items]
Revenue	18.3	11.7	43.8	36.7
Total B2B revenue
Segment Reporting Information [Line Items]
Revenue	379.4	341.4	1,107.8	1,032.3
Subscription revenue
Segment Reporting Information [Line Items]
Revenue	144.6	127.4	418.9	387.6
Non-subscription revenue
Segment Reporting Information [Line Items]
Revenue	234.8	214.0	688.9	644.7
Other revenue
Segment Reporting Information [Line Items]
Revenue	$ 182.2	$ 220.9	$ 704.8	$ 694.4