Expenditures in the United States federal budget
The United States federal budget consists of mandatory expenditures (which includes Medicare and Social Security), discretionary spending for defense, Cabinet departments (e.g., Justice Department) and agencies (e.g., Securities & Exchange Commission), and interest payments on debt. This is currently over half of U.S. government spending, the remainder coming from state and local governments.
Source: Wikipedia — Expenditures in the United States federal budget (CC BY-SA 4.0)