%%DOCGUID
A guaranteed unique ID generated once per document. This variable is only generated if you specify <DOC1GUID> Y. To include the value from this variable in an XML document, specify %%DOCGUID within the <CONTENT> group in the <XMLELEMENT> tag group. 
Valid in Control File Tags
This system variable is valid in the Control File when used in the following tags.
- <ADDPART>
 - <SIDEPART>
 
Valid in Rule File Sections
This system variable is not valid in the rule file.