v2.4.0.6
Loans and Allowance for Credit Losses, Loans by Credit Quality Indicator, Commercial (Details) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2013
Dec. 31, 2012
Dec. 31, 2008
Loans and Leases Receivable Disclosure [Abstract]      
Purchased Credit Impaired Loans $ 29,729 $ 30,968 $ 58,797
Loans 799,966 799,574  
Total Commercial [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Purchased Credit Impaired Loans 3,502 3,977 18,704
Loans 361,714 361,198  
Commercial and Industrial Loans [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Purchased Credit Impaired Loans 191 259 4,580
Loans 185,623 187,759  
Commercial Real Estate Mortgage [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Purchased Credit Impaired Loans 1,839 1,970 5,803
Loans 106,119 106,340  
Commercial Real Estate Construction [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Purchased Credit Impaired Loans 767 877 6,462
Loans 16,650 16,904  
Lease Financing [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Purchased Credit Impaired Loans 0 0  
Loans 12,402 12,424  
Foreign Loans [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Purchased Credit Impaired Loans 705 871 1,859
Loans 40,920 37,771  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Total Commercial [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 358,212 357,221  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Total Commercial [Member] | Pass [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 319,902 315,867  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Total Commercial [Member] | Criticized [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 38,310 41,354  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Commercial and Industrial Loans [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 185,432 187,500  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Commercial and Industrial Loans [Member] | Pass [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 167,516 169,293  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Commercial and Industrial Loans [Member] | Criticized [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 17,916 18,207  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Commercial Real Estate Mortgage [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 104,280 104,370  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Commercial Real Estate Mortgage [Member] | Pass [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 88,613 87,183  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Commercial Real Estate Mortgage [Member] | Criticized [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 15,667 17,187  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Commercial Real Estate Construction [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 15,883 16,027  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Commercial Real Estate Construction [Member] | Pass [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 12,983 12,224  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Commercial Real Estate Construction [Member] | Criticized [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 2,900 3,803  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Lease Financing [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 12,402 12,424  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Lease Financing [Member] | Pass [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 11,776 11,787  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Lease Financing [Member] | Criticized [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 626 637  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Foreign Loans [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 40,215 36,900  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Foreign Loans [Member] | Pass [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans 39,014 35,380  
Loans Excluding Purchased Credit-Impaired Loans [Member] | Foreign Loans [Member] | Criticized [Member]
     
Loans and Leases Receivable Disclosure [Abstract]      
Loans, excluding Purchased Credit Impaired Loans $ 1,201 $ 1,520