WASHINGTON (MarketWatch) - The Federal Reserve is fighting a subpoena for Fed chairman Ben Bernanke to testify in a civil lawsuit challenging Bank of America's takeover of Merrill Lynch & Co in 2008, according to a report in the Wall Street Journal. The lawsuit alleges that Bank of America BAC +0.24% and its former chief executive Kenneth Lewis deceived shareholders about a looming multi-billion loss at Merrill so that Bank of America shareholders would approve the takeover. The government provided a $20 billion bailout to Bank of America after the deal was completed and the loss announced. Shareholder lawyers want to ask Bernanke about conversations he held with Lewis prior to the closing of the transaction in January 2009.