Condensed Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	1 Months Ended		2 Months Ended	3 Months Ended	2 Months Ended	3 Months Ended
	Jan. 23, 2013 Predecessor [Member]	Jan. 23, 2013 Predecessor [Member] CyrusOne L.P. [Member]	Mar. 31, 2013 Successor [Member]	Mar. 31, 2014 Successor [Member]	Mar. 31, 2013 Successor [Member] CyrusOne L.P. [Member]	Mar. 31, 2014 Successor [Member] CyrusOne L.P. [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ (20.2)	$ (20.2)	$ (2.8)	$ 0.7	$ (2.8)	$ 0.7
Depreciation and amortization	5.3	5.3	16.4	27.6	16.4	27.6
Amortization of Financing Costs and Discounts	0.1	0.1	(0.2)	0.9	(0.2)	0.9
Share-based Compensation	0.2	0.2	1.2	2.2	1.2	2.2
Deferred Income Tax Expense (Benefit)	0.3	0.3	0	0	0	0
Increase (Decrease) in Receivables	(9.6)	(9.6)	11.2	(6.7)	11.2	(6.7)
Increase (Decrease) in Accounts Payable and Accrued Liabilities	20.5	20.5	6.1	4.4	6.1	4.4
Increase (Decrease) in Deferred Revenue	3.2	3.2	(4.3)	8.9	(4.3)	8.9
Increase (Decrease) in Accounts Payable, Related Parties	1.5	1.5	(4.7)	(0.1)	(4.7)	(0.1)
Increase (Decrease) in Other Operating Assets and Liabilities, Net	0.7	0.7	0	0	0	0
Net cash provided by (used in) operating activities	2.0	2.0	22.9	37.9	22.9	37.9
Cash flows from investing activities:
Capital expenditures – acquisitions of real estate	0	0	(18.2)	0	18.2	0
Capital expenditures – other development	(7.7)	7.7	(26.7)	(49.7)	26.7	(49.7)
Release of restricted cash	1.9
Proceeds From Release Of Restricted Cash	1.9	1.9	1.8		1.8	0
Net cash provided by (used in) investing activities	(5.8)	(5.8)	(43.1)	(49.7)	(43.1)	(49.7)
Cash flows from financing activities:
Issuance of common stock	0	0	360.5	0	337.1
IPO costs	0		(23.4)	0
Dividends and distributions paid	0	0	0	(10.4)	0	(10.4)
Payments on capital leases and other financing arrangements	(0.6)	0.6	(0.6)	(1.4)	0.6	(1.4)
Contributions from parent, net	0.2	0.2	0	0	0	0
Net cash provided by (used in) financing activities	(0.4)	(0.4)	336.5	(11.8)	336.5	(11.8)
Cash and cash equivalents at beginning of period	16.5	16.5	12.3	148.8		148.8
Cash and cash equivalents at end of period	12.3	12.3	328.6	125.2	328.6	125.2
Supplemental disclosures
Cash paid for interest, net of amount capitalized	0.3	0.3	1.8	1.6	1.8	1.6
Capitalized interest	0	0	0.4	0.5	0.4	0.5
Acquisition of property in accounts payable and other liabilities	15.7	15.7	18.9	52.2	18.9	52.2
Contribution receivable from Parent related to transaction-related compensation	19.6	19.6	0	0	0	0
Dividends payable	0	0	10.3	13.7	10.3	13.7
Deferred IPO costs	1.7		0	0
Deferred IPO costs reclassified to additional paid in capital	0	1.7	9.5	0	0	0
Noncash distributions to CyrusOne Inc.		$ 0			$ 9.5	$ 0