FORMATTING RESULTS IN CALCULATED FIELD

In design view of a query, I am trying to make a new field by subtracting one
field from another. Since the field to be subtracted is sometimes null, I
used this expression:

DUE: Nz(([SNESFee]-[INVOICE AMOUNT]),[SNESFEE])

The results are correct, but I can't change the way they are formatted. I
want it in currency format. It shows no dollar sign and no decimal places.

I tried to change the format to "currency" in the properties box. No good.
I tried to change the format to $#.00 and that's no good either.

Thanking you in advance for any help.