The science policy of the United States is the responsibility of many organizations throughout the federal government.
Much of the large-scale policy is made through the legislative budget process of enacting the yearly federal budget, although there are other legislative issues that directly involve science, such as energy policy, climate change, and stem cell research. Further decisions are made by the various federal agencies which spend the funds allocated by Congress, either on in-house research or by granting funds to outside organizations and researchers.
The USA devoted 2.81% of GDP to research and development (R&D) in 2012. The private sector contributed two-thirds of the total. The Obama administration has fixed a target of a 3% ratio by the end of his presidency in 2016.
Source: https://www.livescience.com/58404-how-federal-science-funding-has-changed.html