1 volt = 1 joule/coulomb
100 volts = 100 joules/coulomb
Work = (100 J/C) x (2 C)
Work = (+ or -) 200 J
The work could be positive or negative. It depends on direction of the potential difference, direction the charge is moved, sign of the charge, and whether we mean work done by the mover or by the potential difference.
But the MAGNITUDE of the work is 200J .