Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities
Net income	$ 11.2	$ 18.6	$ 28.3
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	217.4	199.5	179.5
Loss on extinguishment of debt	13.6	0	46.5
Gain on sale of assets	(1.6)	(8.4)	0
Impairment of goodwill and other assets	14.2	52.4	0
Provision for loss on receivables	13.9	13.9	15.2
Noncash portion of interest expense	7.8	7.7	8.0
Deferred income tax expense, including valuation allowance change	21.6	24.9	38.2
Pension and other postretirement benefits in excess of expense	(28.4)	(19.5)	(10.7)
Stock-based compensation	5.2	4.1	3.3
Excess tax benefit for share based payments	(2.4)	0	0
Other, net	(1.4)	(3.7)	(3.5)
Changes in operating assets and liabilities, net of effects of acquisitions:
Increase in receivables	(33.6)	(10.6)	(26.7)
(Increase) decrease in inventory, materials, supplies, prepaid expenses and other current assets	(14.5)	(5.9)	22.2
(Decrease) increase in accounts payable	(6.9)	19.2	4.6
(Decrease) increase in accrued and other current liabilities	(10.0)	(0.5)	4.0
Decrease (increase) in other noncurrent assets	4.6	1.1	(5.4)
Increase (decrease) in other noncurrent liabilities	2.0	(2.9)	(3.5)
Net cash provided by operating activities	212.7	289.9	300.0
Cash flows from investing activities
Capital expenditures	(367.2)	(255.5)	(149.7)
Acquisitions of businesses, net of cash acquired	0	0	(526.7)
Proceeds from sale of assets	1.6	11.5	0
Increase in restricted cash	(11.1)	0	0
Release of restricted cash	4.9	0	0
Other, net	0	(0.7)	0.9
Net cash used in investing activities	(371.8)	(244.7)	(675.5)
Cash flows from financing activities
Proceeds from issuance of long-term debt	525.0	0	2,134.3
Increase (decrease) in corporate credit and receivables facilities with initial maturities less than 90 days	52.0	0.4	(85.9)
Repayment of debt	(442.4)	(11.5)	(1,554.5)
Debt issuance costs	(20.9)	(0.8)	(42.6)
Dividends paid on preferred stock	(10.4)	(10.4)	(10.4)
CyrusOne stock issuance costs	(5.7)	0	0
Common stock repurchase	(0.3)	(10.4)	(10.0)
Proceeds from exercise of options and warrants	12.1	0.4	0.5
Excess tax benefit for share based payments	2.4	0	0
Financing obligations and other, net	(2.8)	(16.5)	(1.6)
Net cash provided by (used in) financing activities	109.0	(48.8)	429.8
Net (decrease) increase in cash and cash equivalents	(50.1)	(3.6)	54.3
Cash and cash equivalents at beginning of year	73.7	77.3	23.0
Cash and cash equivalents at end of year	$ 23.6	$ 73.7	$ 77.3