Just a little info from the friendly CBO.
The Social Security system is a collective one. Each worker's Social Security taxes are not put aside to pay his or her eventual benefits; instead, they are used to finance the system in general, largely for current retirees. As with other federal levies, Social Security tax receipts go into the U.S. Treasury, and any portion not needed to pay current beneficiaries is used to finance the government's other functions or to reduce its debt.
Who the hell thought of that idea?