How do I show "partnership distributions" from Sonoco?

You should receive a K-1 with the partnership distribution reported.  

Sunoco is a master limited partnership.  As such, as has been noted, you should receive a Schedule K-1.

As a result, you should also be maintaining a tax basis schedule.  This may be provided to you on your K-1, but it is good to maintain this separately or at least confirm the figures on your K-1.

This tax basis schedule is very important as it provides the information to determine your income, losses allowed, taxability of distributions, and eventually your overall gain or loss upon disposition.

Your distributions will not be taxable to the extent you have sufficient tax basis; once again, driving home the importance of maintaining and understanding your tax basis.