Hi,
Hope you are asking about INBOUND IDOCs which are posted into SAP ECC from SAP PI. If that is the question here is the answer
Example scenario:
Sender(some format)---->PI-----> converting and sending in IDOC format to SAP ECC
in SAP ECC we05(or)we02-->select inbound IDOC which you received from SAP PI
step1: select any IDOC number and double click on it
setp 2: click on "control record"
step 3: in "Details" tab-->identification --> EE <SAP PI Message ID>
Take this message id and search in PI, you will find corresponding message in moni
