The amount of money the central bank parceled out was surprising even to Gary H. Stern, president of the Federal Reserve Bank of Minneapolis from 1985 to 2009, who says he “wasn’t aware of the magnitude.” It dwarfed the Treasury Department’s better-known $700 billion Troubled Asset Relief Program, or TARP. Add up guarantees and lending limits, and the Fed had committed $7.77 trillion as of March 2009 to rescuing the financial system, more than half the value of everything produced in the U.S. that year.