Detailed billing reports are similar to AWS Cost and Usage reports. They contain similar information about your charges, but calculate the individual line items differently. If you sign up for both the detailed billing report and the AWS Cost and Usage report, the line items will not match. When the reports are finalized at the end of the month, the total cost should align.
The Detailed Billing Report will be unavailable at a later date. We strongly recommend that you use the AWS Cost and Usage Report instead.