You know, if you ever give your idea to someone employed by a big corporation, they will always respond immediately with “yeah, we've been looking at how we can get that into the next version”.
This way, they deny that you were the first to put the idea into their head, and leave you with no recourse to prove otherwise. Just in the off chance that you feel like turning around and trying to sue them later (and let's face it, statistically speaking, you're probably a lame arse fuckwit like everyone else in the world too).
It's still probably better to be marginalised than let your 'great little idea' be lost though.
Just don't tell 'em your best ones, or anything you're particularly attached to.