Originally Posted by LoganFlyer

Do you have Global Entry? If so, you'll definitely be fine (barring delays on the inbound, of course). If not, you'll probably be fine--even if it takes you an hour to get through customs & immigration, two hours is still plenty of time to get from the exit of E to the outbound gate in terminal A. I'd walk from E to A instead of taking the intra-terminal bus; the route goes through a parking garage and is well-signed. It's about a 10 minute walk.