The US Budget Deficit for Fiscal 2016 is about to close, and various estimates bracket a $600 Billion Deficit. I’ve seen numerous analyses which forecast this to rise to over $1 Trillion over the next few years, largely due to the growth of Social Security, Medicare, & other Health outlays, which currently make up about 2/3 of total federal government outlays.
Here is a wealth of numbers from the Office of the President. (I copied below only a tiny amount because the many graphs didn’t copy well.)

GDP: $16.5T
Total Receipts: $3.34T
Total Outlays: $3.95T
Total Surplus or Deficit as Percentage of GDP: -3.3%
* Note: To the extent feasible, the data have been adjusted using chained 2009 GDP to provide consistency with the 2015 Budget and to provide comparability over time.