Goodwill and Intangible Assets Goodwill (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Goodwill, Gross	$ 64.7us-gaap_GoodwillGross	$ 64.7us-gaap_GoodwillGross
Goodwill, Impaired, Accumulated Impairment Loss [Abstract]
Goodwill, Impaired, Accumulated Impairment Loss	50.3	50.3
Goodwill [Roll Forward]
Goodwill	14.4us-gaap_Goodwill	290.6us-gaap_Goodwill
Goodwill divested from deconsolidation of CyrusOne		(276.2)
Impairment	0us-gaap_GoodwillImpairmentLoss
Goodwill	14.4us-gaap_Goodwill	14.4us-gaap_Goodwill
Wireline [Member]
Goodwill [Roll Forward]
Goodwill	11.8	11.8
Goodwill divested from deconsolidation of CyrusOne		0
Impairment	0
Goodwill	11.8	11.8
IT Services and Hardware [Member]
Goodwill [Roll Forward]
Goodwill	2.6	2.6
Goodwill divested from deconsolidation of CyrusOne		0
Impairment	0
Goodwill	2.6	2.6
Wireless [Member]
Goodwill [Roll Forward]
Goodwill	0	0
Goodwill divested from deconsolidation of CyrusOne		0
Impairment	0
Goodwill	0	0
Data Center Colocation [Member]
Goodwill [Roll Forward]
Goodwill	0	276.2
Goodwill divested from deconsolidation of CyrusOne		(276.2)
Impairment	0
Goodwill	$ 0	$ 0

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

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Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of divestiture of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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