The title is very wrong and the HN comments so far miss the point that windows is a tiny portion of that deal. I don't know the details, but judging by the products involved, I would say no more than 5-10%. Exchange, Sharepoint, all of Office client and server suites, SQL maybe some private cloud, virtualization, monitoring software, dedicated support, maybe some custom DoD regulatory stuff for records management and whatnot, that's what they're paying for.

I do know that the Army was making extensive use of Sharepoint on the fields in Irak for example.