Я or Мне?

Hey. I was watching a Russian movie called "Волкодав," and at some point some guy said: я правлю городом, мне и решать.

I think I understand why "city" is in instrumental case, but what's "мне" doing in there? I would have thought it would just be "я решаю".

Here's a link to where he says it.

This is how I understand it:

Я правлю городом, мне и решать.

I rule the city and (it is) for me to decide.

Just sounds a little better IMO.

мне и решать = я решаю
That is, "I make a decision" is possible to be translated like both "мне и решать" and "я решаю".

Ah, I see. Thanks!