Debt (Details 1) (Corporate, Recourse, Convertible subordinated notes, USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Corporate \| Recourse \| Convertible subordinated notes
Total interest expense recognized on the Convertible Subordinated Notes
Coupon rate interest	$ 17.4	$ 17.4	$ 17.4
Amortized debt discount	14.5	13.4	12.3
Total interest expense recognized on the Convertible Subordinated Notes	$ 31.9	$ 30.8	$ 29.7

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

+ References

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Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

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