Oh, brother.
I suppose at this point we might do our visitors a service, and pre-emptively point out that the Pentagon also does not have a battalion of combat Marines to protect against ground troops, a squadron of tanks, its own fighter wing, etc., in addition to its non-existent anti-aircraft guns or missiles.
Just because it's involved with the military does not mean it's built for combat. It's an office building. It has relatively little tactical military value. Aside from security issues, it's just not that special. Passive measures only.
Otherwise, they would never have built it in such a sensitive area. If you're expecting the heavy heat, you build out in the middle of nowhere, like Cheyenne Mountain or Malmstrom Air Force Base. It would seriously suck to repel an attack, only to have the Capitol wiped out by near misses.
And people are laughing because you should be able to answer these questions for yourself. I would fail a fourth-grade research report that made such assertions. Nothing personal, we like to help, but you must also participate in your own education.