Check out Building Blocks.
Automated Boilerplate Using Microsoft Word

You probably want to use AutoText. (You can save your text as other types of building blocks if you want, the AutoText field will still work.
Create an AutoText entry in a Global Template for each element. Then in your sixteen templates, substitute an AutoText field for the element. (You are using templates, not documents, right? If not, let us know.)

When you want to change something, change the AutoText entry in the global template.

The default name for building blocks is the text at the beginning. This is seldom a good choice for the name. Choose meaningful names that are unique in the first four characters to have them be the most useful.