Consolidated and Combined Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2012 Predecessor [Member]	Dec. 31, 2012 Predecessor [Member] CyrusOne L.P. [Member]	Dec. 31, 2013 Successor [Member]	Dec. 31, 2013 Successor [Member] CyrusOne L.P. [Member]
Allowance for doubtful accounts receivable	$ 0.3	$ 0.3	$ 0.5	$ 0.5
Accumulated amortization of intangible assets	$ 38.2	$ 38.2	$ 55.1	$ 55.1
Preferred stock par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01	$ 0.01
Preferred stock authorized (in shares)	100,000,000	100,000,000	100,000,000	100,000,000
Preferred stock issued (in shares)	0	0	0	0
Preferred stock outstanding (in shares)	0	0	0	0
Common stock par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01	$ 0.01
Common stock shares authorized (in shares)	1,000	1,000	500,000,000	500,000,000
Common stock issued (in shares)	100	100	21,991,669	21,991,669
Common stock outstanding (in shares)	100	100	21,991,669	21,991,669