TurboTax is asking for your retirement benefits paid to you (from any source) as a PA resident. Even though they are paid by DE, because you are a PA resident they are considered PA retirement income for you.
Pennsylvania does not tax commonly recognized retirement benefits paid after you are eligible to retire. So, TurboTax is trying to calculate the amount that of income taxed at a federal level, but not taxed by PA. For you, that is the retirement income paid to you by the DE source.
**Mark the post that answers your question by clicking on "Mark as Best Answer"