People are always sooooo scared to share their ideas with friends, family, and strangers. There is this intrinsic fear that someone is going to steal their "great" idea. I don't want to burst anyone's bubble, but if it's a good idea and in a good space, then someone is probably already doing it and they probably have better funding.
Mike Lazerowe said it best..."you are more likely to destroy your own company than competition. Between funding issues, founder issues, execution issues, and everything inbetween, there is a good chance you may not end up with a billion dollar company. Unicorns are hard to come by in real life and in businesses.
The main issue with having paranoia around an idea is that it's just an idea. The process of building a actual company is 1000x harder than pontificating one drunken night in your room. The only people lucky enough to benefit off of an "idea" are the Winklevoss twins from Facebook and the long lost Snapchat founder. Be open to sharing your idea to people. It's okay. Don't give away all of the IP, trade secrets, and secret sauce, but share it enough so that people can help augment your idea and actually help you make it into a business.