The Department of Defense is a cabinet-level executive branch agency responsible for maintaining and overseeing the US military forces. Its primary functions include overseeing the Army, Navy, Air Force, Marine Corps, and Space Force, as well as creating military policies and managing the defense budget.
In FY 2025, the Department of Defense spent $950.6 billion, which was 13.5% of the $7.04 trillion in overall federal spending. The department's spending has increased by 58.7% since 1980, while overall spending has increased by 196.9%.
The Department of Defense employs approximately 685,000 people, which is 33.9% of the overall federal workforce. The secretary of Defense, nominated by the president and confirmed by the Senate, leads the department.
