Bill, as in currency; e.g., ten-dollar note.
The grandest was the $10,000 note – the largest denomination ever issued by the United States Treasury. (New York Times, June 17, 1990)/As a three-fer (President, saint, writer), Lincoln could have the two-dollar note all to himself. (Hendrik Hertzberg, The New Yorker, February 19, 2007)
notoneoffbritishisms.com 
If you take a look at the one-dollar bill in your pocket, you’ll see that it calls itself a
FEDERAL RESERVE NOTE
and says
THIS NOTE IS LEGAL TENDER FOR ALL DEBTS, PUBLIC AND PRIVATE
The word “bill” is nowhere to be seen.
We don’t need ‘note’ when we’ve got ‘bill’ ! The possible confusion between bill-how-much-I-owe/bill-the piece of currency just adds to the possibilities for double meanings. Go us!