v2.4.0.8
Securities Available for Sale, Major Categories (Details) (USD $)
In Millions, unless otherwise specified
Jun. 30, 2013
Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]    
Cost $ 244,368 $ 223,283
Gross unrealized gains 8,898 12,970
Gross unrealized losses (3,827) (1,054)
Securities available for sale 249,439 235,199
Debt Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 242,158 220,946
Gross unrealized gains 8,303 12,473
Gross unrealized losses (3,779) (1,005)
Securities available for sale 246,682 232,414
US Treasury and Government [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 6,624 7,099
Gross unrealized gains 20 47
Gross unrealized losses (261) 0
Securities available for sale 6,383 7,146
US States and Political Subdivisions [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 40,524 37,120
Gross unrealized gains 1,166 2,000
Gross unrealized losses (800) (444)
Securities available for sale 40,890 38,676
Mortgage Backed Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 141,379 125,471
Gross unrealized gains 5,040 8,034
Gross unrealized losses (2,435) (321)
Securities available for sale 143,984 133,184
Federal agencies [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 110,522 92,855
Gross unrealized gains 2,231 4,434
Gross unrealized losses (2,192) (4)
Securities available for sale 110,561 97,285
Residential [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 12,704 14,178
Gross unrealized gains 1,478 1,802
Gross unrealized losses (65) (49)
Securities available for sale 14,117 15,931
Commercial [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 18,153 18,438
Gross unrealized gains 1,331 1,798
Gross unrealized losses (178) (268)
Securities available for sale 19,306 19,968
Corporate debt securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 20,176 20,120
Gross unrealized gains 987 1,282
Gross unrealized losses (161) (69)
Securities available for sale 21,002 21,333
Collateralized loan and other debt obligations [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 16,647 12,726
Gross unrealized gains 632 557
Gross unrealized losses (78) (95)
Securities available for sale 17,201 13,188
Other Debt Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 16,808 18,410
Gross unrealized gains 458 553
Gross unrealized losses (44) (76)
Securities available for sale 17,222 18,887
Equity Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 2,210 2,337
Gross unrealized gains 595 497
Gross unrealized losses (48) (49)
Securities available for sale 2,757 2,785
Perpetual preferred securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 1,850 1,935
Gross unrealized gains 342 281
Gross unrealized losses (32) (40)
Securities available for sale 2,160 2,176
Other equity securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 360 402
Gross unrealized gains 253 216
Gross unrealized losses (16) (9)
Securities available for sale $ 597 $ 609