To all those doubting $900M+, here's the deal:
The 2nd Week-end of the latest big blockbusters, Jurassic World and Avengers (1st one), had their second week-ends = ~15.6% of their total gross
(In fact, no movie with a second week-end greater than 60 M had a total gross of more than 20% of their second week-end)
So, applying those numbers to Star Wars we get
$153,522,000 / 0.156
= $984,115,384
And that's assuming Star Wars follows Jurassic World and Avengers. It's much more hyped up than them, at least I think, but that's for another day...
source: http://www.boxofficemojo.com/alltime/weekends/moreweekends.htm?page=2&p=.htm
Let's calculate Star Wars's total with Avatar's second week-end-to-total ratio, for fun.
153,522,000 / 0.101
= 1,520,019,802
Avatar is ridiculous.