Discontinued Operations - Revenue by Service Offering (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Discontinued Operations
Total revenue	$ 176.1	$ 181.9	$ 350.7	$ 363.4
Subscription services
Discontinued Operations
Revenue	163.2	168.6	325.2	336.6
Other business services
Discontinued Operations
Revenue	5.4	5.7	10.7	11.3
Other business services - Wholesale and colocation lease revenue
Discontinued Operations
Revenue	4.9	5.0	9.6	9.8
Other revenue
Discontinued Operations
Other revenue	7.5	7.6	14.8	15.5
Residential Subscription | Subscription services
Discontinued Operations
Revenue	135.4	141.3	269.7	282.0
Residential Subscription | HSD
Discontinued Operations
Revenue	84.6	81.5	166.9	161.0
Residential Subscription | Video
Discontinued Operations
Revenue	44.7	52.5	90.4	106.1
Residential Subscription | Telephony
Discontinued Operations
Revenue	6.1	7.3	12.4	14.9
Business Subscription | Subscription services
Discontinued Operations
Revenue	27.8	27.3	55.5	54.6
Business Subscription | HSD
Discontinued Operations
Revenue	18.0	17.2	35.8	34.3
Business Subscription | Video
Discontinued Operations
Revenue	3.0	2.8	5.9	5.6
Business Subscription | Telephony
Discontinued Operations
Revenue	$ 6.8	7.3	$ 13.8	14.7
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale
Discontinued Operations
Total revenue		105.4		210.2
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Subscription services
Discontinued Operations
Revenue		100.8		200.6
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Other business services
Discontinued Operations
Revenue		0.4		1.0
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Other revenue
Discontinued Operations
Other revenue		4.2		8.6
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Residential Subscription
Discontinued Operations
Revenue		91.2		181.5
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Residential Subscription | HSD
Discontinued Operations
Revenue		51.8		102.1
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Residential Subscription | Video
Discontinued Operations
Revenue		35.5		71.5
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Residential Subscription | Telephony
Discontinued Operations
Revenue		3.9		7.9
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Business Subscription
Discontinued Operations
Revenue		9.6		19.1
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Business Subscription | HSD
Discontinued Operations
Revenue		5.9		11.7
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Business Subscription | Video
Discontinued Operations
Revenue		0.9		1.8
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Business Subscription | Telephony
Discontinued Operations
Revenue		$ 2.8		$ 5.6