If you don't see the outline symbols , , and , click Options on the Tools menu, click the View tab, and then select the Outline symbols check box.
Do one or more of the following:
Show or hide the details for a group
Expand or collapse the entire outline to a particular level
For example, if an outline has four levels, you can hide the fourth level while displaying the rest of the levels by clicking .
Show or hide all of the outlined detail