Establishes the congressional budget for the federal government for FY2018 and sets forth budgetary levels for FY2019-FY2027. Recommends levels and amounts for FY2018-FY2027 in both houses of Congress for: federal revenues, new budget authority, budget outlays, deficits, public debt, debt held by the public, and the major functional categories of spending. Recommends levels and amounts for FY2018-FY2027 in the Senate for Social Security and Postal Service discretionary administrative expenses. Includes reconciliation instructions directing: the Senate Finance Committee to submit to the Senate Budget Committee legislation increasing the deficit by no more than $1.5 trillion over FY2018-FY2027, the Senate Energy and Natural Resources Committee to submit to the Senate Budget Committee legislation reducing the deficit by at least $1 billion over FY2018-FY2027, the House Ways and Means Committee to submit to the House Budget Committee legislation increasing the deficit by no more than $1.5 trillion over FY2018-FY2027, and the House Natural Resources Committee to submit to the House Budget Committee legislation reducing the deficit by at least $1 billion over FY2018-FY2027. (Under the Congressional Budget Act of 1974, reconciliation bills are considered by Congress using expedited legislative procedures that prevent a filibuster and restrict amendments in the Senate.) Establishes reserve funds that provide flexibility in applying budget enforcement rules to legislation addressing a wide range of specified issues across the federal budget. Sets forth budget enforcement procedures for legislation considered in the Senate.