Launching your own product is a costly thing. I don't want to discourage you, but...

If you have a billion-dollar-idea, get used to the thought that first of all it is a minus-billion-dollar idea.
Specify your business plan. How much you are going to spend on
- developers
- marketing
- sales process
- support
All together your costs will be approximately equal to a billion of dollars.
And only after you spend that much on your project and if it proves to be successful, then and only then you still have a chance to make the sum you dream of.