Here's how to research a bank's, credit union's, or other financial institution's deposits, loans, credit card loans, home loans and more. You'll see several years' worth of data and get to compare it to other factors like equity, book value of loans and more.
The best database for this is Mergent - at least for large public financial corporations like Bank of America or Capital One. You can see detailed breakdowns of their financial assets.
American Financial Directory is also good. Less detail, and it's in print, but it does have some numbers on loans, liabilities and assets. Particularly good for smaller banks, privately-held banks, and credit unions.
Now, this one is pretty amazing indeed: Federal website where you can check your local bank's deposits, loans, mortgage, etc... figures