Update Title Property to site

Hi All,

Im looking for suggestions from the forum for the following task

I have to update Title property of all the documents in the SharePoint site. There are n(say million) number of existing documents and few hundred SITE COLLECTIONS (will timer job will help. any references ?).

I need the above tasks for NEW documents when uploaded so ultimately I think only event reciever, but challenge is to all document libraries (Im thinking to attach OOB Document ContentType) any real working example will help.

will the solutions can be rewritten in O365? if so what will be the best aproach.