National Defense
Discretionary spending includes paying for all DoD Military personnel, operation and maintenance, procurement, research, and housing. Also, all atomic energy defense (nuclear weapons related stuff) and defense related activities of the FBI and other programs is included here for a total Discretionary budget of 609,859 million dollars.
Mandatory spending includes retirement payments, operation and maintenance, procurement, research, atomic energy defense, and some trusts for a total Mandatory budget of 9,607 million dollars.
International Affairs
This is almost entirely discretionary, with the mandatory category including a few trust funds and loan guarantees. Discretionary spending includes humanitarian assistance ~25 billion dollars, international security assistance (financing of foreign militaries, help with antiterrorism) ~12.8 billion dollars, embassies, culture exchange programs, and financial programs for a total of 58,129 million dollars.
General Science, Space, and Technology
This is funding for the National Science Foundation, Department of Engergy science programs, and NASA. Most of it is discretionary with a small percent being proposed legislation for mandatory spending. The total is 31,909 million dollars.
Energy
This category covers programs relating to energy conservation, renewable energy, emergency preparedness, and regulation. Discretionary spending is 5,417 million dollars and mandatory spending is 3,553 million dollars for a total of 8,970 million dollars.
Natural Resources and Environment
Discretionary spending here involves dams, water reclamation, the forest service and fish and wildlife service, other conservation, land management, state park maintenance, pollution control and abatement, and other programs like NOAA totaling 35,833 million dollars in discretionary spending. 6,334 million dollars in mandatory spending mostly goes into the conservation, recreation (state parks), and pollution control and abatement categories for a grand total of 42,167 million dollars in this category.
Agriculture
Discretionary and Mandatory spending go the same categories here with slight variations in percentage. Those categories are research and education, inspection, and loan programs, for a total of 25,485 million dollars.
Commerce and Housing Credit
This includes FHA loan programs, the Postal service, small business assistance, mortgage programs and deposit insurance (FDIC). Discretionary spending actually comes out to a net gain of 5,228 million dollars thanks to interest on loans and the postal service being slightly profitable. Mandatory spending comes to 7,358 million dollars, but the total spending in this category is only 2,130 million dollars.
Transportation
Highways, trains, airports and airways (FAA), air transport security (TSA, maybe? It doesn't specify), marine safety and transportation, and coast guard retirement pay. This one is pretty simple and every category contains both discretionary and mandatory spending except coast guard retirement pay, which is all mandatory. of course. Discretionary spending totals 24,723 million dollars, while mandatory spending totals 84,100 dollars, for a total of 108,823 million dollars. About 60% of this category goes to ground transport: highways, trains, mass transport, infrastructure, and highway safety.
Community and Regional Development
Discretionary spending: Community development, Indian programs, disaster relief, 17,542 million dollars. Mandatory spending: Housing grants, Indian programs, disaster relief insurance, 12,057 million dollars. Total of 29,599 million dollars.
Education, Training, Employment, and Social Services
Discretionary spending here covers a wide range. ~40 billion is spent on education for the disadvantaged, vocational and other adult education, English as a second language, etc. ~28.5 billion goes to college scholarship and other higher education aid. ~4 billion to Library of Congress, Smithsonian, and PBS tv. And ~24 billion goes to employment programs, rehabilitation services, older citizens employment programs, and other social / training services for a total of 96,865 million dollars discretionary.
Mandatory includes the most of the same categories with ~5 billion in lower education, ~6.7 billion in higher education, and ~19 billion in training and other social services.
Grand total for Education: 127,835 million dollars. Note that these programs only include special services. General K-12 schooling isn't funded at the federal level.
Health
Discretionary spending includes the CDC, NIH, FDA, and other health care, research, training, and safety programs and administrations. Total discretionary spending is 51,569 million dollars. Mandatory spending includes ~377.5 billion dollars in grants to states for Medicaid, ~23 billion for CHIP, and refunds and tax credits for health insurance premiums, plus ~26.7 billion for all DoD and federal employee retirement healthcare benefits for a total of 516,748 million dollars in mandatory spending; 568,317 million dollars total in the health category.
Medicare
Medicare is budgeted separately from the rest of Health. Discretionary spending involves administrative expenses and fraud prevention for 7,019 spend on discretionary Medicare. Mandatory expenses for Medicare come to 598,361 million dollars, for a total in this category of 605,380 million dollars.
Income Security
Most of the 69,641 million dollars in spending in the discretionary section of this category goes to housing assistance. Section 8, homeless assistance, other HUD programs, etc amount to ~46.3 billion dollars. WIC accounts for ~6.5 billion dollars. Other expenses include utilities assistance, refugee assistance, and administration of unemployment compensation. Mandatory spending comes to 480,341 million dollars and includes ~34.8 billion dollars in unemployment compensation, ~106.5 billion dollars in SNAP and other child nutrition programs, and ~184.5 billion dollars in various tax credits and assistances being counted as expenditures. ~144.6 billion dollars in the mandatory category also goes to military and civilian retirement and disability payments adding up to a total of 549,982 million dollars in Income Security spending.
Social Security
There are 5,786 million dollars in administrative expenses budgeted to discretionary expenses. The mandatory Social Security expenses are 970,688 million dollars, for a total of 976,474 million dollars in Social Security expenses.
Veterans Benefits
Discretionary veterans benefits spending includes ~66.7 billion in medical care, plus housing, cemetery administration, and education/training/rehab for employment for a total of 75,377 in discretionary spending. Mandatory spending includes ~86.1 billion dollars in pensions for a total of 103,839 million dollars in mandatory spending. The total coming to 179,216 million dollars in veterans benefits.
Administration of Justice
This includes funding for the FBI, Secret Service, IRS, DEA, other law enforcement agencies, lawyers fees, prison funding, and border patrol. Discretionary spending is 44,860 million dollars, mandatory spending is 14,934 million dollars. The total comes to 59,794 million dollars.
General Government
This category covers all governmental administrative costs such as tax administration, salaries, property management, reelection funds, and other miscellaneous... things. This one has a lot of minutiae. Discretionary spending comes to 19,053 million dollars, mandatory to 12,939 million dollars, for a total of 31,992 million dollars.
Net Interest
Due to the nature of this category, there is no discretionary spending. Spending in this category amounts to 302,697 million dollars. 511,659 million dollars of interest will go to interest on Treasury debt securities. If you have investments in a mutual fund or if you bought savings bonds, much of the interest you make on those things is being paid to you by the government as interest. Almost all of the national debt is composed of money borrowed by buying US treasury bonds and bills (though some of these are bought by other countries). Understanding this makes it clearer why 'paying back the national debt' is not so simple as just having the money to pay it back. How is this interest larger than the total? The government has a number of trust funds and savings accounts for which it collects interest, which is applied to the interest paid out in this category.
Allowances
This is a sort of placeholder category for adding extra costs into the budget later for things like overseas operations. For now, there is only 15,000 million dollars in mandatory outlays allowed for immigration and disaster costs.
Undistributed Offsetting Receipts
Remember offsetting receipts? These are outlays which are paid by one part of the budget to another part of the budget so that without this section, the money would be counted twice. They have been listed previously as outlays, but they are receipts from other areas in the budget. For example, payments made to military personnel include deductions for retirement funds. The entire paycheck amount is counted as an outlay in Military (in the same way that your employer counts your gross pay as your salary, not your net pay), and then the disability deduction from the paycheck is moved to the military retirement fund and paid out, where it counts as part of Income Security. In order to not count this money twice, it's kept track of and deducted from the total budget so that there is no net effect on the budget of moving money from one section to another. The total Offsetting Receipts for this category is 108,488 million dollars, which is subtracted from the total net budget.