You can take any amount of money you wish out of the USA. It doesn't matter what the currency form is nor what type of monetary instrument (cash, checks, money orders, foreign currency).

If you are taking out or bring in more than $10,000 USD (or its foreign equivalent) you simply have to file FinCen Form 105 (Currency Reporting Form).

There is no restriction on how much you can transport (in USD or foreign currency or other monetary instruments), save the form.