How exactly would you get PASSIVE income from your "Ideas''?

An "idea" is not very valuable, and you can't generally protect it. You have to turn that idea into something functional and write some very specific patents around it. For example, the "idea" for a new soft-drink flavor would get you nothing from Coca-Cola. You might be able to protect a very specific formulation of that flavor, pr a brand name for it, but it would not be hard for someone else to work around it by altering it just a bit.