A benefit is a health care service or supply that is paid for in part or in full by Medicare. There are substantial uncovered costs that a supplemental policy can help with. It is important for you to understand that Medicare does not cover everything, and it does not pay the total cost for most services or supplies that are covered.The amount of your coverage is also dependent on whether you have coverage under Medicare Part A, Medicare Part B, or both. Medicare Part A typically pays for your inpatient hospital expenses and Medicare Part B typically covers your outpatient health care expenses including doctor fees.