According to online magazine Foreign Policy, the Pentagon has plans in place in case of a zombie apocalypse.
(I had to check the date on this report, to make sure it wasn't early April, but apparently the US Defense Department has plans, in an unclassified document called "CONOP 8888", with instructions of what to do if zombies attack and the armed forces have to eradicate flesh-eating walkers in order to "preserve the sanctity of human life" among all the "non-zombie humans."
The plans even look at the different kinds of zombie adversaries one might find: