v2.4.0.8
Investment Securities (Investment) (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2013
Jun. 30, 2012
Jun. 30, 2013
Jun. 30, 2012
Dec. 31, 2012
Debt Securities [Member]
Dec. 31, 2011
Debt Securities [Member]
Jun. 30, 2013
Domestic Corporate Debt Securities [Member]
Dec. 31, 2012
Domestic Corporate Debt Securities [Member]
Jun. 30, 2013
US States and Political Subdivisions Debt Securities [Member]
Dec. 31, 2012
US States and Political Subdivisions Debt Securities [Member]
Jun. 30, 2013
Residential Mortgage Backed Securities [Member]
Dec. 31, 2012
Residential Mortgage Backed Securities [Member]
Jun. 30, 2013
Commercial Mortgage Backed Securities [Member]
Dec. 31, 2012
Commercial Mortgage Backed Securities [Member]
Jun. 30, 2013
Asset-backed Securities [Member]
Dec. 31, 2012
Asset-backed Securities [Member]
Jun. 30, 2013
Foreign Corporate Debt Securities [Member]
Dec. 31, 2012
Foreign Corporate Debt Securities [Member]
Jun. 30, 2013
Foreign Government Debt Securities [Member]
Dec. 31, 2012
Foreign Government Debt Securities [Member]
Jun. 30, 2013
US Treasury and Government [Member]
Dec. 31, 2012
US Treasury and Government [Member]
Jun. 30, 2013
Retained Interest [Member]
Dec. 31, 2012
Retained Interest [Member]
Jun. 30, 2013
Available-for-sale Securities [Member]
Dec. 31, 2012
Available-for-sale Securities [Member]
Jun. 30, 2013
Trading Securities [Member]
Dec. 31, 2012
Trading Securities [Member]
Jun. 30, 2013
Total [Member]
Dec. 31, 2012
Total [Member]
Investment [Line Items]                                                            
Investment securities amortized cost             $ 19,924 $ 20,233 $ 4,195 $ 4,084 $ 2,034 $ 2,198 $ 2,905 $ 2,930 $ 6,069 $ 5,784 $ 2,083 $ 2,391 $ 2,198 $ 1,617 $ 886 $ 3,462 $ 70 $ 76 $ 240 $ 513 $ 138 $ 245 $ 40,742 $ 43,533
Investment securities gross unrealized gains             2,662 4,201 296 575 150 183 191 259 12 31 108 150 98 149 69 103 23 7 54 86 0 0 3,663 5,744
Investment securities gross unrealized loss             (182) (302) (175) (113) (68) (119) (101) (95) (94) (77) (99) (126) (8) (3) 0 0 0 0 (17) (3) 0 0 (744) (838)
Investment securities estimated fair value             22,404 24,132 4,316 4,546 2,116 2,262 2,995 3,094 5,987 5,738 2,092 2,415 2,288 1,763 955 3,565 93 83 277 596 138 245 43,661 48,439
Net pre-tax gains (loss) on trading securities 5 13 41 36                                                    
Marketable securities OTTI amounts 152 33 441 65                                                    
Cumulative impairments recognized in earnings associated with debt securities 694 434     420 558                                                
Marketable securities OTTI recorded in AOCI 19 1 30 1                                                    
Marketable Securities, Realized Loss, Other than Temporary Impairments, Amount 133 32 411 64                                                    
Incremental Charges On Previously Impaired Investment Securities 7 6 19 11                                                    
Other Than Temporary Impairment Related To Equity Securities   16 1 23                                                    
Other Than Temporary First Time Impairments Of Investment Securities Recognized In Earnings 122 3 385 10                                                    
Other Than Temporary Impairment Related To Securities Subsequently Sold 46 33 47 169                                                    
Guarantee Provided By Parent Offset 96   96                                                      
Proceeds from Sale of Available-for-sale Securities 4,296 2,742 7,084 6,504                                                    
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities $ 133 $ 32 $ 411 $ 64