Zootopia ran for 17 weeks in the domestic box office, grossing $340,774,225.
Finding Dory has been in theaters for 2 weeks and has already grossed $380,545,558.
Zootopia grossed $176,786,320 after its 2nd week.
Finding Dory is heading towards $500-550M at the domestic box office.
I don't see a scenario where Finding Dory doesn't gross 1B world wide.