I can't follow your calculation.
From
RT.com (thre are other sources)
"Defense spending accounts for 58 percent of the discretionary pie, more than a trillion dollars a year all-in, or almost half of what the entire rest of the world spends combined. "
The other way to look at is is via algebra, and subtract social security from the whole, as it should not be viewed as federal revenue or as an expenditure, it is a benefit plan administered by the federal government. In any case there are a lot of programs that need cutting, though I am not one for eliminating social programs overall, I am in favor of cutting many until there is real pain, but where there is no single program to kill to fix these problems, there are many that I question.
For example: What does the federal department of education do, and how many people does it need to do it? Schools are administered on a local level, and funded via local taxes, so where is the Federal role? I'm not asking rhetorically either. If they are simply evaluating the efficacy of various programs, then maybe a staff of 20 clever people can get it done. Similarly for social programs. Perhaps it is possible to set up homeless shelters that are not dangerous? Should welfare provide anything more than 100 square feet of space and a toaster oven for each person? After all, it is right that people not fear the need to live under a bridge, but a fear of living at the lowers levels of the social ladder is a useful motivator.
http://en.wikipedia.org/wiki/2010_United_States_federal_budget