I sourced spending data from http://www.usgovernmentspending.com/ and revenue data from http://www.usgovernmentrevenue.com/. Lots of good links and transparency wrt data sourcing (mostly from gov) and calculations of totals.

In 2015 Federal spend was 3.8t and revenue was 3.2t, so there was a gap of -600bn there as you mentioned. States ran a surplus of 200bn and local ran a deficit of -400bn. Intergovernmental transfers amounted to 600bn. So the total deficit was -200bn (the top level numbers are rounded to one decimal place).