Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015 units		Mar. 31, 2014	Dec. 31, 2014
Goodwill and Other Intangible Assets [Abstract]
Amortization expense for intangible assets subject to amortization	$ 57.6		$ 65.6
Reporting Units	3
Finite-Lived Intangible Assets [Line Items]
Gross Cost	3,280.9			3,276.8
Accumulated Amortization	(1,570.4)			(1,512.8)
Net Carrying Value	1,710.5			1,764.0
Franchise rights
Finite-Lived Intangible Assets [Line Items]
Gross Cost	1,285.1			1,285.1
Accumulated Amortization	(254.0)			(243.3)
Net Carrying Value	1,031.1			1,041.8
Customer lists
Finite-Lived Intangible Assets [Line Items]
Gross Cost	1,914.0			1,914.0
Accumulated Amortization	(1,249.8)			(1,203.4)
Net Carrying Value	664.2			710.6
Cable franchise rights
Finite-Lived Intangible Assets [Line Items]
Gross Cost	39.8			39.8
Accumulated Amortization	(28.5)			(28.2)
Net Carrying Value	11.3			11.6
Other (a)
Finite-Lived Intangible Assets [Line Items]
Gross Cost	42.0	[1]		37.9
Accumulated Amortization	(38.1)	[1]		(37.9)
Net Carrying Value	$ 3.9	[1]		$ 0

[1] During the first quarter of 2015, we acquired for cash non-exclusive licenses to various patents, which are being amortized on a straight-line basis over the estimated useful life of 3 years.