National Defense is the portion of the budget that funds
military activities of the Department of Defense,
nuclear-weapons activities of the Department of
Energy, and national security programs of several other
agencies, including parts of the Coast Guard and FBI.

Social Security, established in 1935 as a national plan designed to provide economic security for American workers, provides retirement benefits to about 50 million eligible retirees, disabled persons, and their spouses and survivors.

Unemployment and income security programs allocate cash and other types of assistance (housing, nutrition, and energy support) to low- income Americans that benefits some retirees, persons with disabilities and the unemployed.

Medicare is the U.S. federal health insurance program covering more than 44 million Americans over the age of 65, plus younger adults who are disabled or suffer from
end-stage kidney failure.

Health funding covers most direct domestic health care service programs, including Medicaid, health benefits for federal workers and retirees, the National Institutes for Health, the Food and Drug Administration, the Centers for Disease Control and Prevention, and the Indian Health Service.

Other portions of the budget support a range of
domestic activities including education,
agriculture, the environment, transportation,
energy, the federal workforce, and Congress.

Interest on the debt represents the cost to the United States paid by the Federal government to those holding U.S. Treasury securities, essentially servicing the expenses of U.S. government borrowing to finance the national debt.

Foreign Assistance includes a variety of economic,
security, and humanitarian aid programs fighting
global poverty, promoting economic growth in
developing countries, saving lives through focused
health interventions, providing relief to victims of
natural disasters and conflict, expanding American
export opportunities, and supporting key friends of
the United States.