Securitizations and Variable Interest Entities, Key Economic Assumptions - Mortgage Servicing Assets (Details) - Residential mortgage servicing rights [Member] - $ / loan	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Prepayment speed	11.90%	12.90%	12.40%	12.50%
Discount rate	7.60%	7.30%	7.60%	7.60%
Cost to service ($ per loan)	237	301	237	268