The U.S. Constitution provides that Congress shall have the power to "borrow money on the credit of the United States Those notes are "obligations of the United States" and "shall be redeemed in lawful money on demand at the Treasury Department of the United States District of Columbia, or at any Federal Reserve bank". Congress has authorized the issuance of more than 10 other types of banknotes.The Federal Reserve Note is the only type that remains in circulation since the 1970s.