I think 8.5 billion dollars of extra work is very hard to award. I think there are very few people if any people in the U.S. government who could credibly promise to award 8.5 billion dollars of work which Microsoft could bid on.
This is still overseas cash, for which it otherwise doesn't have much use. What's it doing with its spare US cash, which is real money? It's using it to buy back its own shares.
Buying Skype, Nokia and Minecraft is gambling, but what are the odds that one of these will ultimately move the share price more than buying back a few shares?