Restructuring Charges (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Restructuring Reserve [Roll Forward]
Beginning balance	$ 16.8	$ 12.5	$ 13.5		$ 13.5
Charges	0	8.2	2.6	0.9	10.8	3.0
Utilizations	(2.5)	(3.9)	(3.6)
Ending balance	14.3	16.8	12.5		14.3
Restructuring liabilities included in other current liabilities	8.5				8.5		5.8
Restructuring liabilities included in other noncurrent liabilities	5.8				5.8		7.7
Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	8.5	5.9	7.8		7.8
Charges	0	5.4	0.9
Utilizations	(1.2)	(2.8)	(2.8)
Ending balance	7.3	8.5	5.9		7.3
Lease Abandonment [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	8.2	6.5	5.5		5.5
Charges	(0.6)	2.8	1.7
Utilizations	(1.3)	(1.1)	(0.7)
Ending balance	6.3	8.2	6.5		6.3
Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	0.1	0.1	0.2		0.2
Charges	0.6	0	0
Utilizations	0	0	(0.1)
Ending balance	0.7	0.1	0.1		0.7
Wireline [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	10.6	7.9	8.6		8.6
Charges	0	4.4	1.4
Utilizations	(2.1)	(1.7)	(2.1)
Ending balance	8.5	10.6	7.9		8.5
Wireless [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	1.5	1.6	1.6		1.6
Charges	0	0	0
Utilizations	0	(0.1)	0
Ending balance	1.5	1.5	1.6		1.5
IT Services and Hardware [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	0.8	0.2	0.5		0.5
Charges	0	0.7	0
Utilizations	0	(0.1)	(0.3)
Ending balance	0.8	0.8	0.2		0.8
Corporate [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	3.9	2.8	2.8		2.8
Charges	0	3.1	1.2
Utilizations	(0.4)	(2.0)	(1.2)
Ending balance	$ 3.5	$ 3.9	$ 2.8		$ 3.5