Who should you give game ideas to

Game developers typically do not accept idea submissions for a couple of reasons:
One, they often try to avoid legal implications and idea ownership, since game development involves a lot of iterative idea mutation and tangent running. Any finished game is the cumulative effect of hundreds if not thousands or more ideas, and a game may change considerably between concept and alpha product.

Two, game studios typically do no lack for game ideas. Employees in the industry are rarely worker drones with no interest in games. Nearly anyone in the industry can rattle off a half dozen good game ideas, and specialized game designers actively spend part of the day coming up with new whole game ideas, not just game mechanics.

Those caveats aside, the worst a company can do is flatly reject your idea if you submit it to them. Most will have a contact person in the HR department that will answer your questions on what that company does with submissions.

The best way to get your game idea made is to learn how to make it yourself and either do it as an indie project (maybe with like-minded friends or collaborators) or learn the skills to get yourself in the industry and pitch it from inside a company.