I distrust the betting model for extreme probabilities like this.

Can any of us really comprehend that much money? Frankly, I bet even Warren Buffet would have trouble; he has said after he gives away 99% of his wealth, he and his family will have all the money they will ever need. Does 100 times as much money as you'll ever need really feel different from 10x or 1000x?

The betting heuristic is useful because our intuitive sense for money has a much larger dynamic range than our intuitive sense of probability - it's easier to conceptualize "a subway ticket against a nice house" than "million to one odds", but "0.05 subway tickets against 25000 nice houses" doesn't really fit the way we think.