If a car will back out while in reverse without touching the gas?

I have a ford focus and if I put it in reverse I don't even have to hit the gas and it will back up on it's own does the mean the idle is too high?

No - diesel cars will do this easily in most cases. Petrol powered cars will also do it if the clutch is released with care.
Modern fuel injection systems on petrol cars have a responsive idle air control valve that will open the air and fuel intake up to keep the engine running at normal idle speed without driver input.

My guess is that you are referring to start up in the morning and backing out of a garage or parking space. On start up the engine is usually idling at a higher RPM then it does when it is warmed up. So your idle would be higher. And the fact that the reverse gear ratio is lower then all other gears in the trans will help it.

It will move at idle speed- about 6 mph. That's normal.

Why are you asking this? Any car with an automatic transmission will "creep" whether it's in reverse or drive. Even electric cars and hybrids do this with electric engines.