Game ideas aren't worth shit.
Sorry, but it's true.
Think of everyone involved in game development already. All of them have at least a couple of fully fleshed out ideas (and industry vets will have several notebooks worth) for games better than the generic gun porn shooter crap they're currently working, but they're working on it because that's what publishers pay the studio to develope.
If you don't have the cash or a rep that will impress publishers, you're going to have to either go indie or enter the industry and work your way up until you have a chance (and a chance is all it will be) to make your own title.