v2.4.0.8
Securitizations and Variable Interest Entities, Key Economic Assumptions - Mortgage Servicing Rights (Details) (USD $)
 6 Months Ended 12 Months Ended
Jun. 30, 2013
Dec. 31, 2012
Residential Mortgage Servicing [Member]
    
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]    
Fair value of interests held $ 14,185,000,000 $ 11,538,000,000
Expected weighted-average life (in years) 6 years 2 months 12 days 4 years 9 months 21 days
Prepayment speed assumption (annual CPR) 11.40% 15.70%
Decrease in fair value from 10% adverse change 876,000,000 869,000,000
Decrease in fair value from 25% adverse change 2,080,000,000 2,038,000,000
Discount rate assumption 7.60% 7.40%
Decrease in fair value from 100 basis point increase 760,000,000 562,000,000
Decrease in fair value from 200 basis point increase 1,456,000,000 1,073,000,000
Cost to service assumption ($ per loan) 200 219
Decrease in fair value from 10% adverse change 600 615
Decrease in fair value from 25% adverse change 1,499 1,537
Interest-Only Strips [Member]
    
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]    
Fair value of interests held 152,000,000 187,000,000
Expected weighted-average life (in years) 4 years 2 months 12 days 4 years 1 month 8 days
Prepayment speed assumption (annual CPR) 9.90% 10.60%
Decrease in fair value from 10% adverse change 3,000,000 5,000,000
Decrease in fair value from 25% adverse change 8,000,000 12,000,000
Discount rate assumption 18.10% 16.90%
Decrease in fair value from 100 basis point increase 3,000,000 4,000,000
Decrease in fair value from 200 basis point increase 6,000,000 8,000,000
Subordinated bonds [Member] | Commercial Securitizations [Member]
    
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]    
Fair value of interests held 268,000,000 249,000,000
Expected weighted-average life (in years) 4 years 3 months 17 days 4 years 8 months 15 days
Discount rate assumption 1.40% 3.50%
Decrease in fair value from 100 basis point increase 9,000,000 12,000,000
Decrease in fair value from 200 basis point increase 18,000,000 21,000,000
Credit loss assumption 6.80% 10.00%
Decrease in fair value from 10% higher losses 6,000,000 12,000,000
Decrease in fair value from 25% higher losses 14,000,000 19,000,000
Subordinated bonds [Member] | Consumer Securitizations [Member]
    
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]    
Fair value of interests held 41,000,000 40,000,000
Expected weighted-average life (in years) 5 years 11 months 29 days 5 years 10 months 28 days
Prepayment speed assumption (annual CPR) 6.70% 6.80%
Decrease in fair value from 10% adverse change 0 0
Decrease in fair value from 25% adverse change 0 0
Discount rate assumption 4.40% 8.90%
Decrease in fair value from 100 basis point increase 2,000,000 2,000,000
Decrease in fair value from 200 basis point increase 4,000,000 4,000,000
Credit loss assumption 0.40% 0.40%
Decrease in fair value from 10% higher losses 0 0
Decrease in fair value from 25% higher losses 0 0
Senior bonds [Member] | Commercial Securitizations [Member]
    
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]    
Fair value of interests held 929,000,000 982,000,000
Expected weighted-average life (in years) 5 years 5 months 29 days 5 years 3 months 22 days
Discount rate assumption 3.50% 2.20%
Decrease in fair value from 100 basis point increase 43,000,000 43,000,000
Decrease in fair value from 200 basis point increase 82,000,000 84,000,000
Credit loss assumption 0.00% 0.00%
Decrease in fair value from 10% higher losses 0 0
Decrease in fair value from 25% higher losses 0 0
Senior bonds [Member] | Consumer Securitizations [Member]
    
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]    
Fair value of interests held 0 0
Expected weighted-average life (in years) 0 years 0 months 0 days 0 years 0 months 0 days
Prepayment speed assumption (annual CPR) 0.00% 0.00%
Decrease in fair value from 10% adverse change 0 0
Decrease in fair value from 25% adverse change 0 0
Discount rate assumption 0.00% 0.00%
Decrease in fair value from 100 basis point increase 0 0
Decrease in fair value from 200 basis point increase 0 0
Credit loss assumption 0.00% 0.00%
Decrease in fair value from 10% higher losses 0 0
Decrease in fair value from 25% higher losses $ 0 $ 0