Other Asset and Other Liabilities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Components of Other Assets reported on the consolidated balance sheets
Inventory	$ 42.1	$ 39.3
Office furniture, fixtures and other equipment, net of accumulated depreciation	32.7	33.0
Derivatives	17.4	17.6
Deferred financing costs	16.1	14.5
Other investments	6.9	13.6
Prepaid items	12.5	8.7
Other	52.4	60.8
Total	$ 180.1	$ 187.5