v2.4.0.8
Securitizations and Variable Interest Entities, Key Economic Assumptions - Mortgage Servicing Assets (Details) (Residential Mortgage Servicing [Member], USD $)
3 Months Ended 6 Months Ended
Jun. 30, 2013
Jun. 30, 2012
Jun. 30, 2013
Jun. 30, 2012
Residential Mortgage Servicing [Member]
       
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]        
Prepayment speed (annual CPR) 11.70% 13.20% 11.80% 13.20%
Discount rate 7.10% 7.50% 7.10% 7.30%
Cost to service ($ per loan) $ 199 $ 146 $ 189 $ 131