Check out some of the reporting available through Controlling => Product Cost Controlling => Cost Object Controlling => Product Cost by Order => Information System => Summarized Analysis => With Product Drilldown => Variance Analysis.
For some of these, you will want to develop a summarization hierarchy and you will need to run a data collection run (both of these are found in the same menu path => Tools). There's a variety of standard, highly detailed variance reporting available.
Another option is to use COPA - you can map variance categories to different value fields, and do detailed variance reporting from there.