Hasbro does not accept unsolicited game ideas—including for Monopoly. This is standard policy across the toy/game industry. Here's why, and what you can do.
Hasbro's Contact Page typically states: "We do not accept unsolicited ideas, suggestions, or materials." Submissions are deleted/unopened.
Hard Truth: Ideas are cheap; execution, development, art, manufacturing, distribution, and marketing are the value. Hasbro buys proven products, not concepts.
Focus on making a playable prototype. Blind playtest it 20+ times. Then you have something a publisher might license.