around that long, 2 hours, 2 and 1/2 hours max i say.
It ranges from an hour and a half to 2 hours.
It depends what part of philly are you going too. If traffic is very heavy plan to expend in traffic a least 3-4 hours specially if is on a weekend. I travel most of the time to NYC (Long Island) from Delaware and it takes me 5-6 hours in the weekend or rush hours. It takes a little bit less if you go straight Manhattan.