The dominant currency in the world today is the United States Dollar. There have been many versions of U.S. currency, but since 1913, American money has been managed and printed by the Federal Reserve Bank. The Federal Reserve, also known as the Fed does not create money larger than hundred dollar bills. According to Wikipedia, larger bills such as the $1,000 bill have existed in the past.
U.S. Dollars can be used in several countries outside of the United States including British Virgin Islands, Ecuador, Panama, Bahamas, Turks and Caicos, Vietnam, Cambodia, Nicaragua, and Belize. It can also be used in fun ways as you can see in this interesting video.