Goodwill and Intangible Assets Goodwill (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Line Items]
Goodwill, Gross	$ 64.7	$ 340.9
Goodwill, Impaired, Accumulated Impairment Loss [Abstract]
Goodwill, Impaired, Accumulated Impairment Loss	50.3	50.3
Goodwill [Roll Forward]
Goodwill	290.6	290.6
Impairment	0	0	50.3
Goodwill divested from deconsolidation of CyrusOne	(276.2)
Goodwill	14.4	290.6	290.6
Wireline [Member]
Goodwill [Roll Forward]
Goodwill	11.8	11.8
Impairment		0
Goodwill divested from deconsolidation of CyrusOne	0
Goodwill	11.8	11.8
Wireless [Member]
Goodwill [Roll Forward]
Goodwill	0	0
Impairment		0	50.3
Goodwill divested from deconsolidation of CyrusOne	0
Goodwill	0	0	0
IT Services and Hardware [Member]
Goodwill [Roll Forward]
Goodwill	2.6	2.6
Impairment		0
Goodwill divested from deconsolidation of CyrusOne	0
Goodwill	2.6	2.6
Data Center Colocation [Member]
Goodwill [Roll Forward]
Goodwill	276.2	276.2
Impairment		0
Goodwill divested from deconsolidation of CyrusOne	(276.2)
Goodwill	$ 0	$ 276.2