I find it hard to believe the military spends more than Congress gives it. Military doesn't decide the budget either. Of course a lot of pork is reps spending money in their districts to "create jobs", even when the military doesn't want what they're making [0]. Clearly Pentagon isn't in charge of that spending, or they wouldn't be spending money on what they don't want.

[0] https://www.military.com/daily-news/2014/12/18/congress-agai...