Most Welfare programs are run by and funded by the states. The amount that the federal gov't chips in would be under Human Resources. I'm looking for Medicare and I don't see it identified as such on the graph. With human resources at 789 billion it must be in there. When looking for this, I just searched for a budget that didn't include SS and I got this site:
http://www.warresisters.org/pages/piechart.htm it's an old antiwar site, so these numbers are from the 2009 budget. The other controversial part would be how they split the interest on defense and non defense. They admit that their breakdown of 80-20 would differ from other estimates of 60-40. For the purposes of this thread, that difference is small potatoes.
Update:
I think the reason that medicare is not identified on this chart is because it's funding comes from so many different places. Some of it comes from monthly payments of recipients, some comes through pay roll tax, some come from hospital insurance tax, and some comes from a trust fund. This chart would only represents the parts paid for through a tax.