Social Security is NOT part of the budget. It's a self-funded program which has not added a single dime to the deficit. The only relationship between SS and the budget is that Congress has been borrowing from the Social Security trust-fund, but not a dime of expenses have come from the general budget since the program was launched.
If you don't believe me, perhaps if you heard it yourself from the Republican's patron Saint:
http://www.youtube.com/watch?v=ihUoRD4pYzI