v2.4.0.6
Securities Available for Sale, Credit Loss Component (Details) (Debt Securities [Member], USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2012
Mar. 31, 2011
Debt Securities [Member]
   
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]    
Credit loss component, beginning of period $ 1,272 $ 1,043
Initial credit impairments 5 11
Subsequent credit impairments 45 68
Total Additions 50 79
For securities sold (12) (23)
For recoveries of previous credit impairments (8) (12)
Total reductions (20) (35)
Credit loss component, end of period $ 1,302 $ 1,087