Organization and Basis of Presentation - Discontinued Operations, Revenue by Service Offering (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Discontinued Operations
Other revenue	$ 31.4	$ 34.7	$ 39.2
Total revenue	725.7	730.2	727.0
Subscription services
Discontinued Operations
Revenue	672.0	672.1	663.2
Other business services
Discontinued Operations
Revenue	22.3	23.4	24.6
Other business services - Wholesale and colocation lease revenue
Discontinued Operations
Revenue	19.4	19.4	18.8
Residential Subscription | Subscription services
Discontinued Operations
Revenue	561.6	566.5	562.5
Residential Subscription | HSD
Discontinued Operations
Revenue	329.0	294.5	270.3
Residential Subscription | Video
Discontinued Operations
Revenue	204.1	236.4	251.2
Residential Subscription | Telephony
Discontinued Operations
Revenue	28.5	35.6	41.0
Business Subscription | Subscription services
Discontinued Operations
Revenue	110.4	105.6	100.7
Business Subscription | HSD
Discontinued Operations
Revenue	70.1	64.5	59.0
Business Subscription | Video
Discontinued Operations
Revenue	11.4	11.4	11.0
Business Subscription | Telephony
Discontinued Operations
Revenue	28.9	29.7	30.7
Atlantic and Astound broadband markets | Discontinued Operations, Disposed of by sale
Discontinued Operations
Other revenue	13.0
Total revenue	308.3
Atlantic and Astound broadband markets | Discontinued Operations, Disposed of by sale | Subscription services
Discontinued Operations
Revenue	293.7
Atlantic and Astound broadband markets | Discontinued Operations, Disposed of by sale | Other business services
Discontinued Operations
Revenue	1.6
Atlantic and Astound broadband markets | Discontinued Operations, Disposed of by sale | Residential Subscription
Discontinued Operations
Revenue	264.8
Atlantic and Astound broadband markets | Discontinued Operations, Disposed of by sale | Residential Subscription | HSD
Discontinued Operations
Revenue	150.1
Atlantic and Astound broadband markets | Discontinued Operations, Disposed of by sale | Residential Subscription | Video
Discontinued Operations
Revenue	103.2
Atlantic and Astound broadband markets | Discontinued Operations, Disposed of by sale | Residential Subscription | Telephony
Discontinued Operations
Revenue	11.5
Atlantic and Astound broadband markets | Discontinued Operations, Disposed of by sale | Business Subscription
Discontinued Operations
Revenue	28.9
Atlantic and Astound broadband markets | Discontinued Operations, Disposed of by sale | Business Subscription | HSD
Discontinued Operations
Revenue	17.8
Atlantic and Astound broadband markets | Discontinued Operations, Disposed of by sale | Business Subscription | Video
Discontinued Operations
Revenue	2.7
Atlantic and Astound broadband markets | Discontinued Operations, Disposed of by sale | Business Subscription | Telephony
Discontinued Operations
Revenue	$ 8.4
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale
Discontinued Operations
Other revenue		18.3	23.5
Total revenue		418.2	418.8
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Subscription services
Discontinued Operations
Revenue		398.0	392.5
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Other business services
Discontinued Operations
Revenue		1.9	2.8
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Residential Subscription
Discontinued Operations
Revenue		359.9	355.5
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Residential Subscription | HSD
Discontinued Operations
Revenue		185.6	170.4
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Residential Subscription | Video
Discontinued Operations
Revenue		157.4	166.2
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Residential Subscription | Telephony
Discontinued Operations
Revenue		16.9	18.9
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Business Subscription
Discontinued Operations
Revenue		38.1	37.0
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Business Subscription | HSD
Discontinued Operations
Revenue		22.6	21.3
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Business Subscription | Video
Discontinued Operations
Revenue		3.6	3.6
Atlantic and Astound broadband markets | Discontinued Operations, Held-for-sale | Business Subscription | Telephony
Discontinued Operations
Revenue		$ 11.9	$ 12.1