Custom Number Format Problem

I have a user who needs a custom number format formula and I can’t get it to reflect everything I need. They would like all negative values in a given spreadsheet to appear with (or without) dollar signs (depending on how the number was entered) andwith (or without) decimal points (depending on how the number was entered) in black text with parenthesis around the negative value.
As an example, they have a series of numbers, dollar amounts, and FTE’s (with decimal points) and they would like those values to appear as such:

($45.65)
(1.5)
(4565)

For some reason I can get part of the formula built, but then it messes up some of the other numbers or something. Can someone please help me figure this out?!?!