v2.4.0.8
Securities Available for Sale, Credit Loss Component (Details) (Debt Securities [Member], USD $)
In Millions, unless otherwise specified
 3 Months Ended 6 Months Ended
Jun. 30, 2013
Jun. 30, 2012
Jun. 30, 2013
Jun. 30, 2012
Debt Securities [Member]
        
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]        
Credit loss component, beginning of period $ 1,252 $ 1,302 $ 1,289 $ 1,272
Initial credit impairments 4 31 5 36
Subsequent credit impairments 29 43 51 88
Total Additions 33 74 56 124
For securities sold or matured (59) (58) (111) (70)
For recoveries of previous credit impairments (8) (4) (16) (12)
Total reductions (67) (62) (127) (82)
Credit loss component, end of period $ 1,218 $ 1,314 $ 1,218 $ 1,314