The United States budget comprises the spending and revenues of the U.S. federal government. The budget is the financial representation of the priorities of the government, reflecting historical debates and competing economic philosophies. The government primarily spends on healthcare, retirement, and defense programs. The non-partisan Congressional Budget Office provides extensive analysis of the budget and its economic effects. It has reported that large budget deficits over the next 30 years are projected to drive federal debt held by the public to unprecedented levels—from 98 percent of gross domestic product (GDP) in 2020 to 195 percent by 2050. Overview The budget document often begins with the President's proposal to Congress recommending funding levels for the next fiscal year, beginning October 1 and ending on September 30 of the year following. The fiscal year refers to the year in which it ends. However, Congress is the body required by law to pass appropriations annually and to submit funding bills passed by both houses to the President for signature. Congressional decisions are governed by rules and legislation regarding the federal budget process. Budget committees set spending limits for the House and Senate committees and for Appropriations subcommittees, which then approve individual appropriations bills to allocate funding to various federal programs. If Congress fails to pass an annual budget, then several appropriations bills must be passed as "stop gap" measures. After Congress approves an appropriations bill, it is then sent to the President, who may either sign it into law or veto it. A vetoed bill is sent back to Congress, which can pass it into law with a two-thirds majority in each legislative chamber. Congress may also combine all or some appropriations bills into one omnibus reconciliation bill. In addition, the president may request and the Congress may pass supplemental appropriations bills or emergency supplemental appropriations bills. Several government agencies provide budget data and analysis. These include the Government Accountability Office (GAO), the Congressional Budget Office (CBO), the Office of Management and Budget (OMB), and the Treasury Department. These agencies have reported that the federal government is facing many important long-run financing challenges, primarily driven by an aging population, rising interest payments, and spending for healthcare programs like Medicare and Medicaid. President Trump signed the Tax Cuts and Jobs Act into law in December 2017. CBO forecasts that the 2017 Tax Act will increase the sum of budget deficits (debt) by $2.289 trillion