Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue
Services	$ 978.7	$ 933.0	$ 890.2
Products	207.1	234.8	271.3
Total revenue	1,185.8	1,167.8	1,161.5
Costs and expenses
Cost of services, excluding items below	506.4	472.5	416.2
Cost of products sold, excluding items below	172.5	198.1	231.5
Selling, general and administrative	218.7	219.1	204.2
Depreciation and amortization	182.2	141.6	127.6
Restructuring and severance related charges (reversals)	11.9	6.0	(0.4)
Other	1.1	2.5	5.5
Total operating costs and expenses	1,092.8	1,039.8	984.6
Operating Income (Loss)	93.0	128.0	176.9
Interest expense	75.7	103.1	145.9
Loss on extinguishment of debt, net	19.0	20.9	19.6
Gain on sale of CyrusOne investment	(157.0)	(449.2)	(192.8)
Other (income) expense, net	(7.6)	2.6	5.1
Income from continuing operations before income taxes	162.9	450.6	199.1
Income tax expense (benefit)	61.1	159.8	81.4
Income from continuing operations	101.8	290.8	117.7
Income (loss) from discontinued operations, net of tax	0.3	62.9	(42.1)
Net income (loss)	102.1	353.7	75.6
Preferred stock dividends	10.4	10.4	10.4
Net income applicable to common shareowners	$ 91.7	$ 343.3	$ 65.2
Basic earnings per common share from continuing operations	$ 2.17	$ 6.69
Basic earnings (loss) per common share from discontinued operations	0.01	1.50
Basic net earnings per common share	2.18	8.19	$ 1.56
Diluted earnings per common share from continuing operations	2.17	6.68
Diluted earnings (loss) per common share from discontinued operations	0.01	1.49
Diluted net earnings per common share	$ 2.18	$ 8.17	$ 1.56
Weighted-average common shares outstanding - basic	42.0	41.9	41.7
Weighted-average common shares outstanding - diluted	42.1	42.0	41.9
Continuing Operations [Member]
Costs and expenses
Depreciation and amortization	$ 182.2	$ 141.6	$ 127.6
Income tax expense (benefit)	61.1	159.8	81.4
Income from continuing operations	101.8	290.8	117.7
Preferred stock dividends	$ 10.4	$ 10.4	$ 10.4
Basic earnings per common share from continuing operations	$ 2.17	$ 6.69	$ 2.57
Diluted earnings per common share from continuing operations	$ 2.17	$ 6.68	$ 2.56
Discontinued Operations [Member]
Revenue
Total revenue	$ 0.0	$ 4.4	$ 132.8
Costs and expenses
Selling, general and administrative	0.0	2.2	19.5
Depreciation and amortization	0.0	28.6	103.4
Total operating costs and expenses	0.0	39.2	193.9
Operating Income (Loss)	0.0	(34.8)	(61.1)
Other (income) expense, net	(0.3)	(2.3)	2.2
Income tax expense (benefit)	0.0	34.8	(24.0)
Income (loss) from discontinued operations, net of tax	0.3	62.9	(42.1)
Preferred stock dividends	$ 0.0	$ 0.0	$ 0.0
Basic earnings (loss) per common share from discontinued operations	$ 0.01	$ 1.50	$ (1.01)
Diluted earnings (loss) per common share from discontinued operations	$ 0.01	$ 1.49	$ (1.00)