For years, policymakers in both parties have raised questions about taxes on Social Security. Still, eliminating them could create problems for future beneficiaries.

To see if they'll apply to you, you have to calculate your combined income, which is the total of your adjusted gross income, 50% of your annual Social Security income, and any non-taxable income you receive (for example, interest payments from municipal bonds, which are always federally tax-exempt).

Only nine U.S. states continue to require retirees to pay state income taxes on their Social Security benefits: