That's a sham. Only basic stuff is open standard, the rest is proprietary extensions. Such a format can't usually be standardized; there's an entire Wikipedia article about MS' shenanigans to make it happen.
But MS doesn't even keep to that ambiguous 600-pages standard anymore.
Here's fsfe' stance to it, calling it a pseudo-standard.
Which results in basic formatting having to be reverse-engineered. Better use Open Document Format.
Well, christianity was always about people over nature.