Hey, folks. I just flew from IAD to LAX and back. Two hours might be more than you need, but I would say an hour and a half would be the minimum.

And this is only if you have upgraded status. The premier and first class lines were moving decently, but if you were just a regular passenger, you're going to have to wait around an hour or so in line to check bags. Security took around ten minutes to clear. Total waiting time for me was around 30-45 minutes, so I figure that an hour and a half would do the trick.