This will may get your 'headings' as well if you didn't format them with built-in styles.
Code:
Sub BracketsOnBold()
With Selection.Find
.ClearFormatting
.Font.Bold = True
.ParagraphFormat.OutlineLevel = wdOutlineLevelBodyText 'this excludes headings
.Replacement.ClearFormatting
.Text = ""
.Replacement.Text = "[^&]"
.Forward = True
.Wrap = wdFindContinue
.Format = True
.MatchCase = False
.MatchWholeWord = False
.MatchWildcards = False
.MatchSoundsLike = False
.MatchAllWordForms = False
.Execute Replace:=wdReplaceAll
End With
End Sub