Restructuring Charges (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended	3 Months Ended
Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2014
Restructuring Reserve [Roll Forward]
Beginning balance		$ 15.8us-gaap_RestructuringReserve	$ 13.5us-gaap_RestructuringReserve	$ 24.0us-gaap_RestructuringReserve
Charges	9.0us-gaap_RestructuringCharges	15.9us-gaap_RestructuringCharges	13.7us-gaap_RestructuringCharges	3.4us-gaap_RestructuringCharges
Utilizations		(11.4)us-gaap_PaymentsForRestructuring	(11.4)us-gaap_PaymentsForRestructuring	(13.9)us-gaap_PaymentsForRestructuring
Ending balance		20.3us-gaap_RestructuringReserve	15.8us-gaap_RestructuringReserve	13.5us-gaap_RestructuringReserve
Restructuring liabilities included in other current liabilities		20.3us-gaap_RestructuringReserveCurrent	7.8us-gaap_RestructuringReserveCurrent
Restructuring liabilities included in other noncurrent liabilities			8.0us-gaap_RestructuringReserveNoncurrent
Wireline [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		10.5	8.6	15.1
Charges		(0.5)	9.1	3.5
Utilizations		(6.1)	(7.2)	(10.0)
Ending balance		3.9	10.5	8.6
IT Services and Hardware [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		0.8	0.5	2.5
Charges		0	0.7	(1.2)
Utilizations		(0.5)	(0.4)	(0.8)
Ending balance		0.3	0.8	0.5
Wireless [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		1.5	1.6	0.7
Charges		16.3	0.2	1.6	6.4
Utilizations		(2.4)	(0.3)	(0.7)
Ending balance		15.4	1.5	1.6
Data Center Colocation [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		0	0	0
Charges		0	0	0.5
Utilizations		0	0	(0.5)
Ending balance		0	0	0
Corporate Segment [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		3.0	2.8	5.7
Charges		0.1	3.7	(1.0)
Utilizations		(2.4)	(3.5)	(1.9)
Ending balance		0.7	3.0	2.8
Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		9.7	7.8	14.2
Charges		4.2	9.0	2.5
Utilizations		(8.0)	(7.1)	(8.9)
Ending balance		5.9	9.7	7.8
Employee Severance [Member] \| Wireline [Member]
Restructuring Reserve [Roll Forward]
Charges		0.9
Lease Abandonment [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		6.0	5.5	8.1
Charges		(1.4)	4.1	0.9
Utilizations		(2.7)	(3.6)	(3.5)
Ending balance		1.9	6.0	5.5
Contract Terminations [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		0.1	0.2	1.7
Charges		13.1	0.6	0
Utilizations		(0.7)	(0.7)	(1.5)
Ending balance		$ 12.5	$ 0.1	$ 0.2

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

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-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 5.P.4(b))

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Carrying amount as of the balance sheet date of known and estimated obligations associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, which are expected to be paid in the next twelve months or in the normal operating cycle if longer. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, relocating employees, and costs associated with an ongoing benefit arrangement, but excludes costs associated with the retirement of a long-lived asset.

+ References

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section P

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Carrying amount as of the balance sheet date of known and estimated costs associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, which are expected to be paid after one year or beyond the next operating cycle, if longer. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, and costs associated with an ongoing benefit arrangement, but excludes costs associated with the retirement of a long-lived asset.

+ References

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

-Publisher FASB

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