Three hourse minimum
We just got back and here is the process
1) check into the airline. When we got there it seemed like the entire terminal was one long snaking line. This takes at least an hour (We had 1st class so this part was short for us)
2) You get in line to go through security. A double line that took at least 45 minutes (alongside lots of duty free shops that no one dared leave line for to shop in)
3) Then you go through U.S. Immigration
4) Then you get your checked bags back and then go through U.S. Customs
5) Then you give them your checked bags back
6) Then you go through security again (having touched your checked bags you are no longer "clean"
An incredibly cumbersome system