The term "qualified retirement plan" refers to an employer-provided retirement plan, other than a SEP-IRA plan or a SIMPLE IRA plan, that meets the requirements of section 401 of the tax code. These plans include 401(a), 401(k), 403(b), and 457(b) plans. This is different from the term "qualified retirement account" which includes accounts in both qualified retirement plans and IRAs.
Distributions from non-qualified plans (insurance plans and non-qualified annuities) will have a code D included in box 7 of the Form 1099-R reporting the distribution. Distributions from qualified accounts will not use code D.