Contingencies, Guarantees and Indemnifications (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2008	Sep. 30, 2015
Loss contingencies - disclosures
Proceeds from termination of certain structured transactions and the resulting prepayment	$ 440.0
Amount, including interest, attempted to be recovered		$ 550.0
Estimated losses accrued related to legal matters		0.0
Maximum exposure under guarantees		$ 205.0