Microsoft word 2010 has an option to compare two documents where we see the changes in the second document.
To Compare Documents:
1) Click on Review Tab and under Changes category we have a button "Compare" . When we click on that we will get two options Compare and combine. Click Compare
2) We will get the following box where we choose the documents to be compared.
3) We will see the similar items not getting cancelled. and the non similar items getting cancelled.
It will also display the styles of each and every line font and its formatting and changes in the second document.