Other Assets and Other Liabilities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Components of Other Assets reported on the consolidated balance sheets
Inventory	$ 49.1	$ 42.1
Office furniture, fixtures and other equipment, net of accumulated depreciation	35.8	32.7
Derivatives	10.2	17.4
Deferred financing costs	14.8	16.1
Assets held for sale	10.1	0.5
Assets held for sale	6.5	6.4
Prepaid items	9.5	12.5
Other	50.7	52.4
Total	$ 186.7	$ 180.1