Fair Value Disclosure (Details 3) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Document Period End Date	Sep. 30, 2013
Assets
Loans	$ 120.3	$ 27.2
Carrying Amount [Member]
Assets
Investment funds	1.7	2.5
Loans	120.3	27.2
Liabilities
Recourse fixed rate debt	2,684.8	2,343.3
Recourse floating rate debt	937.0	809.1
Nonrecourse debt	75.2	130.6
Fair Value [Member]
Assets
Investment funds	5.3	5.8
Loans	120.6	27.7
Liabilities
Recourse fixed rate debt	2,794.6	2,513.4
Recourse floating rate debt	947.2	807.9
Nonrecourse debt	$ 77.7	$ 138.2