Acquisitions (Schedule of Acquisition) (Details) (USD $) In Millions, unless otherwise specified			0 Months Ended		0 Months Ended		0 Months Ended				0 Months Ended		0 Months Ended		0 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Jul. 03, 2014 Atlanta NAP [Member]	Jun. 30, 2014 Atlanta NAP [Member]	Jul. 03, 2014 Neo [Member]	Jun. 30, 2014 Neo [Member]	Aug. 01, 2013 CoreLink [Member]	Oct. 02, 2013 Access [Member]	Sep. 30, 2014 Access [Member]	Oct. 01, 2013 Access [Member]	Oct. 02, 2013 FiberLink [Member]	Sep. 30, 2014 FiberLink [Member]	Mar. 04, 2014 CoreXchange [Member]	Sep. 30, 2014 CoreXchange [Member]	May 16, 2014 Geo [Member]	Sep. 30, 2014 Geo [Member]
Business Acquisition [Line Items]
Acquisition date			Jul. 01, 2014		Jul. 01, 2014		Aug. 01, 2013	Oct. 01, 2013			Oct. 02, 2013		Mar. 04, 2014		May 16, 2014
Cash acquired						$ 4.2	$ 0.1			$ 1.2					$ 13.7
Other current assets				0.3		13.1	0.5			2.3	0.8		0.7		10.7
Property and equipment				9.7		42.9	15.9			11.5	15.9		3.0		219.5
Deferred tax assets, net				0.1			0			0	7.7		0.2
Intangibles assumed				30.4		13.4	0.2		18.0	18.0	19.3	19.3	10.1	10.1	61.2	61.2
Goodwill	874.3	845.3		13.6		25.0	3.0			24.0	19.8		4.7		90.2
Other assets						2.4	0.5				0.1				9.9
Total assets acquired				54.1		101.0	20.2			57.0	63.6		18.7		405.2
Current liabilities				1.3		10.3	0.7			1.0	1.3		0.6		16.9
Deferred revenue				0.3		6.3	0.2			5.1	19.2		0.4		44.3	44.3
Capital lease obligations							14.3						0.2
Deferred tax liability, net						6.3	3.0			9.6					38.0
Total liabilities assumed				1.6		22.9	18.2			15.7	20.5		1.2		99.2
Net assets acquired				52.5		78.1	2.0			41.3	43.1		17.5		306.0
Less cash acquired						(4.2)	(0.1)			(1.2)					(13.7)
Net cash paid			$ 52.5		$ 73.9		$ 1.9	$ 40.1			$ 43.1		$ 17.5		$ 292.3