How do I propose an investor/company to lend me money for an invention w/o telling them what it is?

Basically, I have an amazing invention that is extremely promising. The problem is, I don't have the money to patent the idea to protect me against someone stealing my idea. What I need is direction on how to get the money while attempting to instill in someone security to lend me money. There would be a great deal of return but again, getting the investor is extremely hard to come by. Thanks for your insight!