v2.4.0.8
Mortgage Banking Activities, Amortized Mortgage Servicing Rights (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 6 Months Ended
Jun. 30, 2013
Jun. 30, 2012
Jun. 30, 2013
Jun. 30, 2012
Dec. 31, 2012
Changes in amortized MSRs          
Amortization $ (62) $ (56) $ (124) $ (114)  
Valuation Allowance          
Amortized MSRs, net 1,176   1,176   1,160
Amortized [Member]
         
Changes in amortized MSRs          
Balance, beginning of period 1,181 1,074 1,160 1,445  
Purchases 26 78 53 92  
Servicing from securitizations or asset transfers 31 34 87 (293)  
Amortization (62) (56) (124) (114)  
Balance, end of period 1,176 1,130 1,176 1,130  
Valuation Allowance          
Balance, beginning of period 0 0 0 (37)  
Reversal of provision for MSRs in excess of fair value 0 0 0 37  
Balance, end of period 0 0 0 0  
Fair value of amortized MSRs:          
Beginning of period 1,404 1,263 1,400 1,756  
End of period $ 1,533 $ 1,450 $ 1,533 $ 1,450