Looking at the numbers

The Treasury has released its “Fiscal Year 2017 Financial Report of the U.S. Government”. The report separates cash results from complete results. Net Operating Cost ($1.157 trillion) is defined as revenues minus costs,which I interpret as complete results. The Budget Deficit ($665.7 billion) is defined as receipts minus outlays (cash spent). The difference of $491 billion between the two is, according to the report, “primarily due to accrued costs (incurred but not necessarily paid) related to increases in estimated federal employee and veteran benefits liabilities and certain other liabilities that are included in net operating cost, but not the budget deficit.”

Here's where the $3.4 trillion in revenues came from: 
80% from Individual income tax and tax withholdings, including Social Security 
9% from Corporation income taxes 
11% from other revenue. 

The costs of $4.5 trillion were divided up as follows: 
24% Department of Health and Human services 
22% Social Security 
15% Department of Defense 
11% Department of Veterans Affairs 
22% All other 
6% Interest on Treasury Securities held by the public