v2.4.0.6
Securities Available For Sale, Major Categories (Details) (USD $)
Mar. 31, 2012
Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]    
Cost $ 221,575,000,000 $ 215,571,000,000
Gross unrealized gains 10,655,000,000 10,211,000,000
Gross unrealized losses (1,964,000,000) (3,169,000,000)
Securities available for sale 230,266,000,000 222,613,000,000
Debt Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 218,840,000,000 212,642,000,000
Gross unrealized gains 10,193,000,000 9,660,000,000
Gross unrealized losses (1,920,000,000) (3,106,000,000)
Securities available for sale 227,113,000,000 219,196,000,000
US Treasury and Government [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 4,642,000,000 6,920,000,000
Gross unrealized gains 43,000,000 59,000,000
Gross unrealized losses (7,000,000) (11,000,000)
Securities available for sale 4,678,000,000 6,968,000,000
US States and Political Subdivisions [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 33,809,000,000 32,307,000,000
Gross unrealized gains 915,000,000 1,169,000,000
Gross unrealized losses (487,000,000) (883,000,000)
Securities available for sale 34,237,000,000 32,593,000,000
Mortgage Backed Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 132,658,000,000 127,105,000,000
Gross unrealized gains 7,379,000,000 6,987,000,000
Gross unrealized losses (886,000,000) (1,352,000,000)
Securities available for sale 139,151,000,000 132,740,000,000
Federal agencies [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 98,409,000,000 92,279,000,000
Gross unrealized gains 4,293,000,000 4,485,000,000
Gross unrealized losses (37,000,000) (10,000,000)
Securities available for sale 102,665,000,000 96,754,000,000
Residential [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 16,491,000,000 16,997,000,000
Gross unrealized gains 1,582,000,000 1,253,000,000
Gross unrealized losses (244,000,000) (414,000,000)
Securities available for sale 17,829,000,000 17,836,000,000
Commercial [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 17,758,000,000 17,829,000,000
Gross unrealized gains 1,504,000,000 1,249,000,000
Gross unrealized losses (605,000,000) (928,000,000)
Securities available for sale 18,657,000,000 18,150,000,000
Corporate debt securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 19,274,000,000 17,921,000,000
Gross unrealized gains 1,034,000,000 769,000,000
Gross unrealized losses (135,000,000) (286,000,000)
Securities available for sale 20,173,000,000 18,404,000,000
Collateralized debt obligations [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 9,031,000,000 8,650,000,000
Gross unrealized gains 366,000,000 298,000,000
Gross unrealized losses (234,000,000) (349,000,000)
Securities available for sale 9,163,000,000 8,599,000,000
Other Debt Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 19,426,000,000 19,739,000,000
Gross unrealized gains 456,000,000 378,000,000
Gross unrealized losses (171,000,000) (225,000,000)
Securities available for sale 19,711,000,000 19,892,000,000
Equity Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 2,735,000,000 2,929,000,000
Gross unrealized gains 462,000,000 551,000,000
Gross unrealized losses (44,000,000) (63,000,000)
Securities available for sale 3,153,000,000 3,417,000,000
Perpetual preferred securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 2,224,000,000 2,396,000,000
Gross unrealized gains 224,000,000 185,000,000
Gross unrealized losses (43,000,000) (54,000,000)
Securities available for sale 2,405,000,000 2,527,000,000
Other equity securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Cost 511,000,000 533,000,000
Gross unrealized gains 238,000,000 366,000,000
Gross unrealized losses (1,000,000) (9,000,000)
Securities available for sale $ 748,000,000 $ 890,000,000