"This report discusses the FY2018 defense budget request and provides a summary of congressional action on the National Defense Authorization Act (NDAA) for fiscal year (FY) 2018. The annual NDAA authorizes appropriations for the Department of Defense (DOD) and defense-related nuclear energy programs of the Department of Energy and typically includes provisions affecting DOD policies or organization. Unlike an appropriations bill, the NDAA does not provide budget authority for government activities. [...] In terms of the total amounts they would authorize (counting funds for base budget and OCO [Overseas Contingency Operations]) the House and Senate proposals differ by slightly more than $3 billion (less than 0.5%). The House bill's $689.0 billion total would exceed the Administration's request by $29.2 billion (about 4.4%), whereas the Senate proposal would exceed the request by $32.3 billion or about 4.8%. The differences between the two bills reflect, in large part, differences in how the chambers categorize and allocate funding for base budget purposes while minimizing the amount by which base budget spending would exceed the BCA (Budget Control Act) cap. Neither bill would modify the FY2018 BCA limit."
CRS Report for Congress, R45013
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html