v2.4.0.6
Securities Available for Sale, Residential Mortgage-Backed Securities, Credit Loss Component (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2012
Mar. 31, 2011
Credit Impairment Losses On Residential Mortgage Backed Securities [Abstract]    
Securities available for sale $ 51 $ 80
Non-agency residential MBS non-investment grade [Abstract]    
Expected remaining life of loan losses From 0.01 0.02
Expected remaining life of loan losses To 0.44 0.26
Credit impairment distribution [Abstract]    
0 - 10% range 46.00% 57.00%
10 - 20% range 11.00% 25.00%
20 - 30% range 1.00% 18.00%
Greater than 30% 42.00% 0.00%
Weighted average 0.09 0.09
Current subordination levels [Abstract]    
Current subordination levels From 0 0
Current subordination levels To 0.57 0.11
Current subordination levels Weighted average 0.02 0.05
Prepayment speed (annual CPR)    
Prepayment speed From 0.05 0.05
Prepayment speed To 0.29 0.15
Prepayment speed Weighted average 0.15 0.10
Residential [Member]
   
Credit Impairment Losses On Residential Mortgage Backed Securities [Abstract]    
Securities available for sale 14 62
Investment Grade [Member] | Residential [Member]
   
Credit Impairment Losses On Residential Mortgage Backed Securities [Abstract]    
Securities available for sale 0 5
Non-investment Grade [Member] | Residential [Member]
   
Credit Impairment Losses On Residential Mortgage Backed Securities [Abstract]    
Securities available for sale $ 14 $ 57