v2.4.0.6
Securitizations and Variable Interest Entities, Key Economic Assumptions - Mortgage Servicing Rights (Details) (USD $)
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
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 $ 11,538,000,000 $ 12,918,000,000
Expected weighted-average life (in years) 4 years 9 months 21 days 5 years 1 month 3 days
Prepayment speed assumption (annual CPR) 15.70% 14.80%
Decrease in fair value from 10% adverse change 869,000,000 895,000,000
Decrease in fair value from 25% adverse change 2,038,000,000 2,105,000,000
Discount rate assumption 7.40% 7.10%
Decrease in fair value from 100 basis point increase 562,000,000 566,000,000
Decrease in fair value from 200 basis point increase 1,073,000,000 1,081,000,000
Cost to service assumption ($ per loan) 219 218
Decrease in fair value from 10% adverse change 615 582
Decrease in fair value from 25% adverse change 1,537 1,457
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 187,000,000 230,000,000
Expected weighted-average life (in years) 4 years 1 month 8 days 4 years 7 months 5 days
Prepayment speed assumption (annual CPR) 10.60% 10.70%
Decrease in fair value from 10% adverse change 5,000,000 6,000,000
Decrease in fair value from 25% adverse change 12,000,000 15,000,000
Discount rate assumption 16.90% 15.60%
Decrease in fair value from 100 basis point increase 4,000,000 6,000,000
Decrease in fair value from 200 basis point increase 8,000,000 12,000,000
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 249,000,000 240,000,000
Expected weighted-average life (in years) 4 years 8 months 15 days 5 years 3 months 17 days
Discount rate assumption 3.50% 3.80%
Decrease in fair value from 100 basis point increase 12,000,000 9,000,000
Decrease in fair value from 200 basis point increase 21,000,000 18,000,000
Credit loss assumption 10.00% 10.70%
Decrease in fair value from 10% higher losses 12,000,000 8,000,000
Decrease in fair value from 25% higher losses 19,000,000 18,000,000
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 40,000,000 45,000,000
Expected weighted-average life (in years) 5 years 10 months 28 days 6 years 1 month 3 days
Prepayment speed assumption (annual CPR) 6.80% 6.90%
Decrease in fair value from 10% adverse change 0 0
Decrease in fair value from 25% adverse change 0 1,000,000
Discount rate assumption 8.90% 11.90%
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% 0.50%
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 982,000,000 852,000,000
Expected weighted-average life (in years) 5 years 3 months 22 days 4 years 4 months 24 days
Discount rate assumption 2.20% 2.40%
Decrease in fair value from 100 basis point increase 43,000,000 31,000,000
Decrease in fair value from 200 basis point increase 84,000,000 59,000,000
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 0 321,000,000
Expected weighted-average life (in years) 0 years 0 months 0 days 5 years 7 months 5 days
Prepayment speed assumption (annual CPR) 0.00% 13.90%
Decrease in fair value from 10% adverse change 0 2,000,000
Decrease in fair value from 25% adverse change 0 4,000,000
Discount rate assumption 0.00% 7.10%
Decrease in fair value from 100 basis point increase 0 12,000,000
Decrease in fair value from 200 basis point increase 0 24,000,000
Credit loss assumption 0.00% 4.50%
Decrease in fair value from 10% higher losses 0 1,000,000
Decrease in fair value from 25% higher losses $ 0 $ 2,000,000