U.S. Strategic Nuclear Forces: Background, Developments, and Issues [February 10, 2017] [open pdf - 1004KB]
"Even though the United States is in the process of reducing the number of warheads deployed on its long-range missiles and bombers, consistent with the terms of the New START [Strategic Arms Reduction Treaty] Treaty, it also plans to develop new delivery systems for deployment over the next 20-30 years. The 115th Congress will continue to review these programs, and the funding requested for them, during the annual authorization and appropriations process. [...] The Obama Administration completed a review of the size and structure of the U.S. nuclear force, and a review of U.S. nuclear employment policy, in June 2013. This review has advised the force structure that the United States will deploy under the New START Treaty. It is currently implementing the New START Treaty, with the reductions due to be completed by 2018. The Trump Administration has indicated that it will conduct a new review of the U.S. nuclear force posture. Congress will review the Administration's plans for U.S. strategic nuclear forces during the annual authorization and appropriations process, and as it assesses U.S. plans under New START and the costs of these plans in the current fiscal environment. This report will be updated as needed."
CRS Report for Congress, RL33640
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html