Assisting Family Farmers through Insurance Reform Measures Act of 2020 or the AFFIRM Act of 2020 This bill requires the Department of Agriculture (USDA) to reduce federal crop insurance payments and to disclose details regarding subsidies. Specifically, the bill requires USDA to annually disclose to the public specified details regarding the recipients and amounts of federal crop insurance subsidies; prohibits certain premium subsidies, including for additional coverage for any person or legal entity that has an average adjusted gross income that is greater than $250,000, and for policies that are based on the actual market price of an agricultural commodity at the time of harvest; establishes an annual cap on total reimbursements for administrative and operating costs of crop insurance providers that begins at $900 million for 2020 and is adjusted for inflation in each subsequent year; and eliminates a requirement that any renegotiated Standard Reinsurance Agreement (SRA) be budget-neutral. (The SRA is an agreement between USDA and the private companies that administer the federal crop insurance program that specifies details such as administrative and operating expense reimbursements and risk sharing. Eliminating the budget neutrality requirement permits USDA to use the renegotiation of the SRA to achieve savings.)