United States uses the United States dollar (symbol: $), code USD.
Banknotes come in denominations of 100, 50, 20, 10, 5, 2 and 1 dollars. Dollar is subdivided into 100 cents. Coins come in denominations of 1, ½ and ¼ dollars and 10, 5 and 1 cents.
Currency name, symbol, ratio (subunits), code and it's denominations (both as banknotes and coins). Exchange rate is coming soon.
Currency category is available in production API version 2.