You would say Two Hundred Ninety-Nine million.
This is because:
First, you just remove all the 0s at the end of the number, from your mind. You just look at the three biggest numbers, and then think about how to say them.
299
So the two would be two hundred, because it is in the hundreds spot.
the 99 would be ninety nine, because um, yee.
So then it would be Two hundred Ninety Nine.
Then look at the 0s. Since there are 6 0s, we know that the 299 is in the millions spot. So we can just say,
Two hundred Ninety-Nine Million.
I don't know if I needed to explain this much... eh