Supplemental Cash Flow Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplemental Cash Flow Information [Abstract]
Capitalized interest expense	$ 0.6	$ 2.7	$ 3.5
Interest	179.5	217.9	211.8
Income taxes, net of refunds	2.8	0.1	(1.2)
Noncash Investing and Financing Items [Abstract]
Investment in CyrusOne resulting from deconsolidation	509.7	0	0
Accrual of CyrusOne dividends	7.1	0	0
Acquisition of property by assuming debt and other financing arrangements	7.6	19.9	49.7
Acquisition of property on account	13.3	30.7	22.8
Accrued CyrusOne stock issuance costs	$ 0	$ 2.2	$ 0