Federal Reserve Chairman Ben Bernanke is briefing Congress on the economy, which has been walloped by high energy prices and fallout from the housing slump and credit crunch.

Bernanke is to appear Tuesday before the Senate Banking Committee. His testimony comes just two days after the Fed and the Treasury Department came to the rescue of mortgage giants Fannie Mae and Freddie Mac, offering to throw them a financial lifeline.

The companies hold or guarantee more than $5 trillion in mortgages — almost half of the nation's total. The Bush administration is asking Congress to increase lines of credit to Fannie and Freddie and to let the government buy their stock. The Fed has offered to let the companies draw emergency loans.