Wow indeed. According to the Office of the Comptroller of the Currency's June 30, 2008 report, commercial bank and trust companies hold $134.85 billion in gold and precious metals derivatives. JPM holds $96.15 billion of that total.
According to the U.S. Mint, the depository at Fort Knox hold 147.3 million troy ounces of gold (exactly who owns that gold is a subject for another post). Using $723.00 as the price per ounce, the value would be $106.5 billion. The Federal Reserve Bank held 266 million troy ounces in 2004, according to their publications. Once again, the Fed safeguards the gold for other countries and entities, so the entire balance is not owned by the U.S.