"On May 23, 2017 the Trump Administration released its federal budget request for fiscal year (FY) 2018. The Administration proposed a total budget of $677.1 billion for national defense-related activities of the federal government (budget function 050). Of the national defense total, $667.6 billion is discretionary spending provided, for the most part, by the annual appropriations bill drafted by the Appropriations Committees of the House and Senate. The remaining $9.6 billion is mandatory spending, that is, spending for entitlement programs and certain other payments. Mandatory spending is generally governed by statutory criteria and it is not provided by annual appropriation acts. As has been typical in recent years, about 95% of that total ($646.9 billion) is for military activities of the Department of Defense (DOD)--referred to as subfunction 051. The balance of the function 050 request comprises $21.8 billion for defense-related atomic energy-defense activities of the Department of Energy (designated subfunction 053) and $8.4 billion for defense-related activities of other agencies (designated subfunction 054) of which about two-thirds is allocated to the Federal Bureau of Investigation."
CRS Report for Congress, R44866
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html