Reasonable request. I thought that by starting with "isn't it true" I was implying that I didn't know.
Also, the person who provided the source was someone else, so if you're asking for a source re my question, perhaps someone will provide it. In any case your poke got me wondering and doing a bit of research.
I must admit, those numbers seem dramatically out of line with my intuition as well. If I was a betting man I'd say there's a bit more to the story, but then the source (https://www.cbpp.org/about/mission-history) seems fairly left leaning so if there was any bending of the truth I'd expect it in the other direction.
Perhaps the reason this feels off is because it's the government budget, which is a subset of the overall economy obviously. And, a lot of the dollars spent here are going back into corporations, for varying levels of return on the dollar I'm sure. I think this is why the numbers sound so great/generous, but don't match reality when you look out the window, watch the news, or read the newspaper.
You may be thinking of how Congress funds the wars in Iraq and Afghanistan. They do indeed fall outside of the ‘planned’ DoD budget, even though we’ve been at war for 17+ years. They’re funded by special appropriations bills.
This 16% ($605 billion) number includes $74 billion in a special Overseas Contingency Operations bill for Afghanistan.
Alternatively, you may also be thinking of the DoD ‘black budget’, which is classified. That is included in the budget, but it’s not itemized or described in any way to keep what it’s spent on a secret. It’s typically around $65 billion.