I have 2 different hair colors, if dyed one color, will they come out the same?

My hair is black with blonde peek-a-boo highlights and the top layer of my hair has chestnut "streaks" I guess you could say. (no, I didn't plan all of the different colors, my mom screwed it up) Anyway, I want to dye my whole hair dark brown/brunette and I was wondering if the dye will even out my hair color or would some of my hair be lighter than the others?