Enacts a new deduction for individual taxpayers under GS 105-153.5. Allows a taxpayer to deduct the amount received from the federal government as retirement pay for a retired US Armed Forces member who has served at least 20 years. Bars also deducting the same amount under the existing deduction provided for certain State, local and federal government retirement plans under subdivision (b)(5). Makes conforming changes. Effective for taxable years beginning on or after January 1, 2021.