It depends. If your 1099-R has a box 7 code of 1, this is a distribution subject to penalty. Thus, if you have a code 1 in box 7 of your 1099-R, you do need to determine the amount of pension you received before you turned 59 1/2 and after turning 59 1/2. (If, on the other hand, you have another code in the box, such as a 2, your distribution is not subject to penalty. It is subject to income tax regardless of the time of the distribution).The amount you received before turning 59 1/2 is subject to penalty, unless an exception applies. (You would have an exception, for example, if you started taking your pension if you were separated from work. This exception applies to anyone 55 years of age and older).
As far as splitting the amounts is concerned, you may need to contact your plan administrator if you are unsure of the amounts. You can, however, enter the amount you received on the Exception to Penalty Screen as shown in the screenshot below:
{edited 1/28/18: 4:46 PST}
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
