WASHINGTON (MarketWatch) -- Treasury Secretary Henry Paulson said the plan to buy troubled bank assets would cost "hundreds of billions" of dollars. "This needs to be big enough to make a real difference and get at the heart of the problem," Paulson told reporters at a brief press conference. Paulson said the plan would include features to protect the taxpayer "to the maximum extent possible." "The ultimate taxpayer protection will be the stability this troubled asset relief program provides to our financial system, even as it will involve a significant investment of taxpayer dollars," Paulson said.