This week, the Senate is debating a mammoth farm bill that will determine U.S. food policy for the next decade. The old farm bill expires this year and its replacement is 1,010 pages long, costingsome $969 billion over 10 years. So what’s actually in it?

The Congressional Budget Office has a handy breakdown (pdf) of many of the provisions of the bill, which I’ve redone in simplified pie-chart form:

Let’s go through the different provisions (some of these are likely to change as various amendments get bandied about):

Food stamps and nutrition, $768.2 billion over 10 years. This is by far the biggest part of the farm bill, with the bulk of it taken up by the Supplemental Nutrition Assistance Program, which helps low-income families pay for food. As my colleague Suzy Khimm reported, Democrats and Republicans have been wrangling over whether to cut this aid by block-granting it to the states. They’re also mulling over different provisions to eliminate fraud.

Commodity programs, $43.2 billion over 10 years. In past years, this was a large part of various farm bills, which often provided “direct payments” to farmers regardless of how much they actually planted or how much they would sell their crops for. This latest farm bill would cut most of these direct payments, saving about $20 billion over 10 years, according to the CBO. (There are still, however, billions of dollars in disaster assistance and subsidized loans for various farmers.) This is arguably the biggest change in the bill — and, as Jonathan Ahl reports, it’s a contentious one among farmers.

Crop insurance, $94.6 billion over 10 years. This is one of the most controversial parts of the farm bill. For decades, farmers have been able to buy crop insurance in case their crops fail or prices decline. The federal government currently pays about $7 billion per year to help cover the premiums. But under the new Senate farm bill, the government would also spend an additional $2 billion per year covering the deductibles that farmers have to pay before the insurance kicks in. This is supposed to help cushion the blow from the loss of direct payments. But critics have warned that this program could cost far more, depending on how crop prices fluctuate.

Conservation, $57.7 billion over 10 years. This includes programs to help farmers protect against soil erosion and to use ecologically friendly methods like drop irrigation. According to the CBO, this part of the farm bill was cut by about $6.5 billion (compared with previous bills) — mainly because the government will be supervising less land.

Trade, $3.4 billion over 10 years. These programs involve promoting U.S. crops overseas and offering food aid abroad. The government also provides some technical assistance to farmers in developing countries.

Energy, $1.4 billion over 10 years. This includes money for biofuels as well as energy efficiency in rural areas.

Miscellaneous, about $6 billion over 10 years. This includes everything from forestry programs to rural development to research and development. There are programs for promoting farmers markets, selling off timber on federal lands, and even research into organic agriculture. Some Republicans, like Arizona Sen. John McCain, have criticized some of the smaller provisions in here — like a $700 million program to study pine-tree growth in Florida or a $40 million program to encourage landowners to share their land with birdwatchers and hunters.

Related: NPR’s Scott Neuman has a nice primer on the history of the farm bill and why it’s so important. Politico’s David Rogers has an in-depth look at the political wrangling. And in the Los Angeles Times, Dan Imhoff and Michael Dimock have an op-ed making the case for several deeper reforms to the bill — from including protections for farmworkers to more research on how climate change could affect agriculture.