In a recently released report of the Inspector General of the Defense Department, improper adjustments of $6.5 trillion for 2015 was highlighted. The adjustments were done without any invoices or receipts and were done to balance the books. Considering that the Defense Department is probably one of the biggest public money spenders; this is definitely very concerning.
Congress on its part has set September 30, 2017 deadline for the complete audit of Department of Defense spendings, which considering the  magnitude of the adjustment will be a miracle if they are ready by then! Maybe they can fight their way through this….
Update: I just read that the errors of $6.5 trillion were partly associated with system glitches. There were around 16,000 files that got wiped off the computer system of the Defense Finance and Accounting Service (DFAS) because of a flaw in the computing software!!!