Industry experts (including insiders at Disney) note that breakeven was approximately 1.5 billion (the 2 billion came from Cameron), accounting for marketing expenses, the theaters' share of ticket sales, and the fact that the bloated number includes the entire filming costs for Avatar 3 and a quarter of Avatar 4.
So Avatar 2 has earned Disney a profit of at least $250m and it still has several more weeks without any competition. And Avatar 3 will have a far lower break-even point.