Except, when it's running on ARM chips. Windows RT, as the ARM-based Windows 8 operating system is called, will not come with the full office, but rather only a Preview that will lack macros, VBA support, third party add-ins and a “small number” of other features. Bummer. The reason for that disappointing decision allegedly comes from battery life and reliability concerns.
The Office 2013 RT Preview will get an upgrade to a final version sometime in 2013.
It wasn’t all that unexpected - Microsoft has kept suspiciously quiet and practically refused to talk Windows RT in depth suggested there’s a reason for that. Now, it’s clearer that just as the Office it ships with, the system itself give the full Windows experience - you wouldn’t be able to go out of the Metro (oops, Windows 8-style) interface, and it wouldn’t support existing Windows applications.