have (something) in (one's) hands
To have under one's control, charge, or care; to have responsibility for something. With his father gone, Mike has the company's future in his hands.
have someone or something in one's hands
1. Lit. to hold someone or something in one's hands. (Have can be replaced with leave or put.) I have the tools you need in my hands, ready to give them to you when you need them.
2. Fig. to have control of or responsibility for someone or something. (Have can be replaced with leave or put.) You have the whole project in your hands. The boss put the whole project in your hands.