Rich Text Format is well documented enough, you could "roll your own" so to speak for simple documents. Word docs are so non-standard and constantly changing as to be a dangerous format to code to for longevity.
PDF and RTF are two of several choices of more well defined standards you can create pretty easily, and XML might be a nice choice for creation of a table someone can import into a word document via excel or whatever high powered import functions their system had.
We do a lot of tab delimited files for things like palm pilots at work, it's very easy to pump out data like that.