Above is a chart of the respective percentage of GDP of state/local and federal spending. Notice that state and local is by far the largest amount of spending. However, this is a but of a misnomer as the Federal government gives money to states in a variety of ways. So,
Let's look at a chart of all government spending as a percentage of chained GDP. Notice the total government spending as a percentage of chained 2000 GDP has fluctuated between 17.4% and 18.4%. Whether this is good or bad is a matter of opinion and -- more importantly -- political ideology.
The BEA breaks down federal spending into defense and non-defense spending. Above is achart of defense and non-defense spending in chained 2000 dollars. Notice that defense spending is roughly twice as large as non-defense spending.
Finally, we have a chart of defense spending as a percentage of federal spending in chained 2000 dollars. Bottom line: defense spending comprises the bulk of federal spending.