It depends. Most large corporations don`t accept submissions outside of their own R&D department. You can probably go to their web site and check their FAQ.
If they do accept outside submissions from independent inventors, you need to protect yourself as much as you can by filing for a patent, if possible. (You want to at least check and make sure your idea isn`t already patented too.)
It`s really hard to guide you without knowing what you`ve done so far for research or protection. There are a number of books on licensing inventions to companies. My suggestion would be to get one or more of those books.