v2.4.0.6
Mortgage Banking Activities, Amortized Mortgage Servicing Rights (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Changes in amortized MSRs      
Amortization $ (233) $ (264) $ (228)
Valuation Allowance      
Provision for mortgage servicing rights in excess of fair value 0 (34) (3)
Amortized mortgage servicing rights, net 1,160 1,408  
Fair value of amortized MSRs:      
Beginning of period 1,756 1,812 1,261
End of period 1,400 1,756 1,812
Amortized [Member]
     
Changes in amortized MSRs      
Balance, beginning of period 1,445 1,422 1,119
Adjustments from adoption of consolidation accounting guidance 0 0 (5)
Purchases 177 155 58
Servicing from securitizations or asset transfers (229) 132 478
Amortization (233) (264) (228)
Balance, end of period 1,160 1,445 1,422
Valuation Allowance      
Balance, beginning of period (37) (3) 0
Provision for mortgage servicing rights in excess of fair value 37 (34) (3)
Balance, end of period 0 (37) (3)
Amortized mortgage servicing rights, net $ 1,160 $ 1,408 $ 1,419