Debt - Credit Facilities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended										12 Months Ended		12 Months Ended				12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2013	Dec. 31, 2013 Line of Credit [Member]	Dec. 31, 2013 Standby Letters of Credit [Member]	Dec. 31, 2013 Bridge Loan [Member]	Dec. 31, 2013 Revolving Credit Facility [Member]	Dec. 31, 2013 Tranche B Term Loan [Member]	Sep. 30, 2013 Tranche B Term Loan [Member]	Dec. 31, 2013 Tranche B Term Loan [Member] London Interbank Offered Rate (LIBOR) [Member]	Dec. 31, 2013 Senior Notes due 2017 [Member]	Oct. 15, 2013 Senior Notes due 2017 [Member]	Dec. 31, 2012 Senior Notes due 2017 [Member]	Dec. 31, 2013 Receivables Facilities [Member]	Dec. 31, 2012 Receivables Facilities [Member]	Dec. 31, 2011 Receivables Facilities [Member]	Dec. 31, 2013 London Interbank Offered Rate (LIBOR) [Member]	Dec. 31, 2013 London Interbank Offered Rate (LIBOR) [Member] Tranche B Term Loan [Member]	Dec. 31, 2013 London Interbank Offered Rate (LIBOR) [Member] Receivables Facilities [Member]	Dec. 31, 2013 Base Rate [Member]	Dec. 31, 2013 Base Rate [Member] Tranche B Term Loan [Member]	Dec. 31, 2013 Federal Funds Rate [Member]	Dec. 31, 2013 Federal Funds Rate [Member] Tranche B Term Loan [Member]	Dec. 31, 2013 Minimum [Member]	Dec. 31, 2013 Maximum [Member]	Dec. 31, 2012 CyrusOne LP [Member]	Jan. 24, 2013 CyrusOne LP [Member] Line of Credit [Member]	Jan. 24, 2013 CyrusOne LP [Member] Standby Letters of Credit [Member]	Jan. 24, 2013 CyrusOne LP [Member] Bridge Loan [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					$ 125	$ 150		$ 200	$ 30	$ 25																					$ 225	$ 50	$ 30
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum																					3.50%	1.00%		2.50%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum																					4.25%			3.25%
Debt Instrument, Interest Rate, Stated Percentage												4.00%			8.25%						4.00%			3.00%
Debt Instrument, Basis Spread on Variable Rate														3.00%							1.00%	1.00%	0.50%		2.00%	0.50%	0.50%
Line of Credit Facility, Interest Rate at Period End											4.15%
Line of Credit Facility, Increase (Decrease), Other, Net		50
Long-Term Debt, Required Principal Payments		0.25%
Debt Instrument, Face Amount													540.0		0	500.0	500.0
Proceeds received from Tranche B Term Loan		536.0	525.0	0								529.8
Debt Instrument, Redemption Price, Percentage	104.125%
Accrued interest																20.6
Issuance of Long-Term Debt, Original Issue Discount	0.75%	0.75%
Loss on extinguishment of debt		29.6	13.6	0
Restricted payments, limit when leverage ratio threshold not attained	15	15
Leverage Ratio, threshold	3.50	3.50
Restricted payments, limit when leverage ratio threshold is attained	45	45
Leverage Ratio, threshold, other	3.00	3.00
Restricted Payments, Share Repurchases or Dividends, limit	15.00%	15.00%
Restricted Payments, Share Repurchases or Dividends, cap	35	35
Proceeds from Sale of Equity Method Investment, Percent Required for Mandatory Debt Prepayments	85.00%	85.00%	100.00%
Equity Interests in Foreign Subsidiaries	66.00%	66.00%
Line of Credit Facility, Amount Outstanding	40.0	40.0	0																											0
Line of Credit Facility, Remaining Borrowing Capacity	160.0	160.0
Line of Credit Facility, Commitment Fee Percentage																												0.50%	0.625%
Line of Credit Facility, Commitment Fee Amount		1.0	1.6	2.3														0.7	0.7	0.7
Receivables facility maximum borrowing capacity	120.0	120.0					105.0
Receivables facility maximum borrowing availability	111.4	111.4
Accounts Receivable Facility, Renewal Term	364	364
Receivables facility amount outstanding	106.2	106.2	52.0
Letters of Credit Outstanding, Amount	$ 5.2	$ 5.2
Debt Instrument, Interest Rate During Period																		0.70%