I haven't looked at the numbers in a couple of years, but I feel confident if we cut our budget in half we would still double the spending of our nearest rival.
And I'd be right.
List of countries by military expenditures - Wikipedia, the free encyclopedia
I doubt the figure even includes our War Budget.
I would never be like Donald Rumsfeld, and walk into the Pentagon and declare the American military the new "enemy" (as he did just before 9/11), and I would never "go private" with the military (as we have). We need a smaller, leaner, and more capable force. Cutting the budget would immediately incentivize to make the fighting force - the pointy end of the spear - more effective.
Unless, of course, what you really need is just bodies for occupation rotations in foreign countries....