v2.4.0.8
Fair Value, Estimates for Financial Instruments Not Carried at Fair Value (Details) (USD $)
In Millions, unless otherwise specified
Jun. 30, 2013
Dec. 31, 2012
Jun. 30, 2012
Dec. 31, 2011
Financial assets:        
Cash and due from banks $ 17,939 $ 21,860 $ 16,811 $ 19,440
Federal funds sold, securities purchased under resale agreements and other short-term investments 148,665 137,313    
Mortgages held for sale 38,785 47,149    
Loans held for sale 190 110    
Loans 801,974 799,574    
Nonmarketable equity investments (cost method) 6,519 6,799    
Financial liabilities:        
Deposits 1,021,585 1,002,835    
Short-term borrowings 56,983 57,175    
Long-term debt 123,375 127,379    
Carrying amount [Member]
        
Financial assets:        
Cash and due from banks 17,939 21,860    
Federal funds sold, securities purchased under resale agreements and other short-term investments 148,665 137,313    
Mortgages held for sale 3,383 4,844    
Loans held for sale 188 104    
Loans 768,071 763,968    
Nonmarketable equity investments (cost method) 6,519 6,799    
Financial liabilities:        
Deposits 1,021,585 1,002,835    
Short-term borrowings 56,983 57,175    
Long-term debt 123,364 127,366    
Estimated fair value [Member]
        
Financial assets:        
Cash and due from banks 17,939 21,860    
Federal funds sold, securities purchased under resale agreements and other short-term investments 148,665 137,313    
Mortgages held for sale 3,383 4,853    
Loans held for sale 194 112    
Loans 773,296 772,351    
Nonmarketable equity investments (cost method) 8,087 8,231    
Financial liabilities:        
Deposits 1,022,057 1,003,942    
Short-term borrowings 56,983 57,175    
Long-term debt 125,959 130,283    
Estimated fair value [Member] | Level 1 [Member]
        
Financial assets:        
Cash and due from banks 17,939 21,860    
Federal funds sold, securities purchased under resale agreements and other short-term investments 3,834 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 144,831 132,267    
Mortgages held for sale 2,395 3,808    
Loans held for sale 181 83    
Loans 57,917 56,237    
Nonmarketable equity investments (cost method) 1 2    
Financial liabilities:        
Deposits 971,375 946,922    
Short-term borrowings 56,983 57,175    
Long-term debt 114,926 119,220    
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 988 1,045    
Loans held for sale 13 29    
Loans 715,379 716,114    
Nonmarketable equity investments (cost method) 8,086 8,229    
Financial liabilities:        
Deposits 50,682 57,020    
Short-term borrowings 0 0    
Long-term debt $ 11,033 $ 11,063