Weird problem exporting to Excel

[UniqueTII]

I have a report that lists a student's Social Security Number, Name, Department, Job Title, and Work-Study eligibility, and when I view the report, everything shows up fine. The problem is that when I send the report to a mail recipient as an Excel file, some of the Social Security numbers get changed to integers, and they're all between -450,000 and -520,000. Anyone have any idea why this happens to them? If I change the cells to SSN after the export, it doesn't fix the problem because the wrong value is already there. What else should I look for?

 

[UniqueTII]

I just exported the query that the report is based on, and all of the data came through fine. Hopefully that helps track down the problem.