It's much worse then just hundreds of millions.
https://msutoday.msu.edu/news/2017/msu-scholars-find-21-trillion-in-unauthorized-government-spending-defense-department-to-conduct/
But for the first time ever the entire DOD is being audited, even though it's supposed to have been done yearly since the 90's.
https://www.defense.gov/News/Article/Article/1391471/officials-announce-first-dod-wide-audit-call-for-budget-certainty/