v2.4.0.6
Fair Value, Estimates for Financial Instruments Not Carried at Fair Value (Details) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2013
Dec. 31, 2012
Mar. 31, 2012
Dec. 31, 2011
Financial assets:        
Cash and due from banks $ 16,217 $ 21,860 $ 17,000 $ 19,440
Federal funds sold, securities purchased under resale agreements and other short-term investments 143,804 137,313    
Mortgages held for sale 46,702 47,149    
Loans held for sale 194 110    
Loans 799,966 799,574    
Nonmarketable equity investments (cost method) 6,649 6,799    
Financial liabilities:        
Deposits 1,010,733 1,002,835    
Short-term borrowings 60,693 57,175    
Long-term debt 126,191 127,379    
Carrying amount [Member]
        
Financial assets:        
Cash and due from banks 16,217 21,860    
Federal funds sold, securities purchased under resale agreements and other short-term investments 143,804 137,313    
Mortgages held for sale 4,078 4,844    
Loans held for sale 194 104    
Loans 764,756 763,968    
Nonmarketable equity investments (cost method) 6,649 6,799    
Financial liabilities:        
Deposits 1,010,733 1,002,835    
Short-term borrowings 60,693 57,175    
Long-term debt 126,179 127,366    
Estimated fair value [Member]
        
Financial assets:        
Cash and due from banks 16,217 21,860    
Federal funds sold, securities purchased under resale agreements and other short-term investments 143,804 137,313    
Mortgages held for sale 4,074 4,853    
Loans held for sale 203 112    
Loans 774,684 772,351    
Nonmarketable equity investments (cost method) 8,148 8,231    
Financial liabilities:        
Deposits 1,011,638 1,003,942    
Short-term borrowings 60,693 57,175    
Long-term debt 129,654 130,283    
Estimated fair value [Member] | Level 1 [Member]
        
Financial assets:        
Cash and due from banks 16,217 21,860    
Federal funds sold, securities purchased under resale agreements and other short-term investments 4,505 5,046    
Mortgages held for sale 0 0    
Loans held for sale 0 0    
Loans 0 0    
Nonmarketable equity investments (cost method) 0 0    
Financial liabilities:        
Deposits 0 0    
Short-term borrowings 0 0    
Long-term debt 0 0    
Estimated fair value [Member] | Level 2 [Member]
        
Financial assets:        
Cash and due from banks 0 0    
Federal funds sold, securities purchased under resale agreements and other short-term investments 139,299 132,267    
Mortgages held for sale 3,032 3,808    
Loans held for sale 190 83    
Loans 57,607 56,237    
Nonmarketable equity investments (cost method) 2 2    
Financial liabilities:        
Deposits 956,330 946,922    
Short-term borrowings 60,693 57,175    
Long-term debt 118,812 119,220    
Estimated fair value [Member] | Level 3 [Member]
        
Financial assets:        
Cash and due from banks 0 0    
Federal funds sold, securities purchased under resale agreements and other short-term investments 0 0    
Mortgages held for sale 1,042 1,045    
Loans held for sale 13 29    
Loans 717,077 716,114    
Nonmarketable equity investments (cost method) 8,146 8,229    
Financial liabilities:        
Deposits 55,308 57,020    
Short-term borrowings 0 0    
Long-term debt $ 10,842 $ 11,063