The $X trillion missing from Pentagon funds is a meme that pops up every few years (new "journalists" discovering the same news and trying to fill their click quota?).
The money is not missing, just not tracked up to expected accounting standards
I don't see the reference to the money as "missing". My read is that it's the total of ledger entries made without sufficient supporting justification.
It could be a tank squadron on the books that wasn't removed when it got destroyed (or dismantled) or a whole military base decommissioned but still being depreciated.
This isn't (necessarily) "the Army spent 6.5 trillion too much in one year" nor is it "the Army lost 6.5 trillion".
A single dollar mistakenly accounted upfront can sometimes require at least twice that in corrective ledger entries.
Finally, consider a mistake of the type of over-estimating the value of a capital item by an order of magnitude. The corrective ledger entry would make it look like a huge loss was incurred in a particular year when the reality was much more benign. For the purposes of this report, that corrective entry needs to be supported by specific explanation which was missing.
The money is not missing, just not tracked up to expected accounting standards
Article from 2013: https://www.reuters.com/article/us-usa-pentagon-waste-specia...
Article from 2002: https://www.cbsnews.com/news/the-war-on-waste/
And you can Google [missing trillions] to find an article on the topic from any given year.