Word 2010 introduced a couple of enhancements to the Navigation Pane, which has been a standard part of prior versions of the app for years. Paragraphs with either automatic numbering or heading styles applied appear in the Navigation Pane.
With the Navigation Pane visible, click a heading to jump to it. In Word 2010, select a heading level in the Navigation Pane and drag it to a different place in the document. Any subsequent text or subordinate headings that follow move with it to the new position.
Word also introduced some limited ability to promote and demote heading levels within a document. Right-click an item in the Navigation Pane to see available controls.
Enable the Navigation Pane
On the View ribbon, check Navigation Pane.