He wanted 3 branches of power. They are as follows: executive, legislative, and judicial. The government was separated into three branches for a major reason. He did not want any one person to be too powerful and control the people weather it's the president, a politician, etc. If ever needed a system called Check and Balances is installed as well. That allows all the braches to check up on one another at any given time. The 3 branches ordeal must have been a fantastic idea since it's implanted in our government to this very day.
Hope this helps!!