Sen. Max Baucus, D-Mont., the Finance Committee chairman, and Sen. Charles E. Grassley, D-Iowa are demanding details of the last-minute sale of failing investment bank Bear Stearns to JP Morgan, and how the Federal Reserve Bank's backing for the deal could affect taxpayers. The Senators wrote to executives of both firms, Treasury Secretary Henry M. Paulson and Fed Chairman Benjamin S. Bernanke seeking answers on how taxpayers would fare under the deal, which the Fed helped broker and guarantee in an extraordinary move aimed at preventing a meltdown of the U.S. financial system.