Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 7.9	$ 7.4
Receivables, less allowances of $12.4 and $12.4	138.5	157.1
Inventory, materials and supplies	21.7	20.6
Prepaid expenses	16.9	13.1
Other current assets	3.3	2.2
Total current assets	188.3	200.4
Property, plant and equipment, net	995.0	975.5
Investment in CyrusOne	52.8	55.5
Goodwill	14.3	14.3
Deferred income taxes, net	177.4	182.9
Other noncurrent assets	16.8	17.8
Total assets	1,444.6	1,446.4
Current liabilities
Current portion of long-term debt	14.8	13.8
Accounts payable	118.4	128.9
Unearned revenue and customer deposits	27.1	29.2
Accrued taxes	12.4	14.5
Accrued interest	23.0	11.2
Accrued payroll and benefits	30.6	31.2
Other current liabilities	24.2	25.0
Other current liabilities from discontinued operations	2.0	5.4
Total current liabilities	252.5	259.2
Long-term debt, less current portion	1,226.0	1,223.8
Pension and postretirement benefit obligations	221.4	225.0
Other noncurrent liabilities	36.3	36.6
Total liabilities	1,736.2	1,744.6
Shareowners' Deficit [Abstract]
Preferred stock, 2,357,299 shares authorized, 155,250 shares (3,105,000 depositary shares) of 6 3/4% Cumulative Convertible Preferred Stock issued and outstanding at March 31, 2016 and December 31, 2015; liquidation preference $1,000 per share ($50 per depositary share)	129.4	129.4
Common shares, $.01 par value; 480,000,000 shares authorized; 210,170,716 and 210,017,999 shares issued; 210,029,666 and 209,876,949 shares outstanding at March 31, 2016 and December 31, 2015	2.1	2.1
Additional paid-in capital	2,574.1	2,576.0
Accumulated deficit	(2,827.2)	(2,834.2)
Accumulated other comprehensive loss	(169.5)	(171.0)
Common shares in treasury, at cost	(0.5)	(0.5)
Total shareowners' deficit	(291.6)	(298.2)
Total liabilities and shareowners' deficit	$ 1,444.6	$ 1,446.4