Deleting

It is possible to delete any styles which you are not using.
There are two ways you can delete unwanted styles
1) Using the Styles and Formatting task pane
2) Using the Organiser dialog box.

Using the Styles and Formatting Task Pane

select the stye
right click and choose delete

You cannot delete the built-in styles from the All Styles view in the Styles and Formatting task pane.
You can delete them from all the other views.

Using the Organiser

(Tools > Templates and Add-ins)
click Organiser
select the style
You can use a combination of the Ctrl + Shift keys to select multiple styles and then press Delete.

Important

If you delete a paragraph style then the Normal style will be automatically applied to any text that has that style applied.