Possible error in Contributions and Membership Details report
You don't specify the version of CiviCRM you're using? Depending on CiviCRM version, you might be seeing one of these issues -


CRM-16636 Duplicate primary addresses causes error in report (issue opened as a result of this response, see comments)
CRM-16338 Incorrect Contribution Summary Report when a contributions has multiple soft credits (&lt;= 4.6.3)
CRM-15374 Contribution FEES are affecting Balance and Total Paid incorrectly (&lt;= 4.5.1)
CRM-11703 Contribution and Membership Details report showing incorrect contribution amounts (&lt;= 4.2.8)


You could search https://issues.civicrm.org/ for other issues if none of those seems like your case (you'll know if you're using soft credits, contribution fees etc).

If you are seeing the issue on a version of CiviCRM that is marked fixed above, post a message on that issue URL - you may be able to assist by providing some (anonymised) example DB data for the core team.