The best place to find this kind of information is in the WorldShare Analytics > Collection Evaluation > My Library report by filtering on the Formats eJournals/Emagazines and ENewspapers. This report is at the title level so you shouldn't have duplicates for different issues. It does include holdings from the WorldCat knowledge base so long as an OCN is attached to the title.
You can find more information about how to filter Collection Evaluation reports.