If you have a lot of money to invest, it is possible to hire companies to make your games. If you do not have money (or a very strong brand or intellectual property, such as Tom Clancy or The Avengers) then you will need more than only an idea. The games industry is full of people with amazing ideas. Ideas are not the problem – the magic comes in the execution. If you strongly believe that your idea will sell millions, channel that belief and confidence into investing the time into learning how to make games, prototype your idea, and pitch it to publishers for investment, or polish the game and release it by yourself or with a team. There are no shortcuts in game development!