When working in ArchiCAD to create 2D documentation, two tools are regularly referred to: Detail tool and Worksheet tool.
Both are separate toolbox entries in the Document section of the Toolbox (as shown below) and both have 'folder' entries in the Navigator 'Project Map'.

Both tools do have similar workflows, but practically, the Worksheet tool is an enhanced version of the Detail tool.
The Detail tool is an older tool and cannot be integrated in as many ways as the Worksheet tool.

In our opinion, the Detail tool should have simply been enhanced with new functionality, (rather than adding a new separate Worksheet tool) as the architectural implication of the phrase 'Details' draws most users to this tool.

Also in our opinion, the Detail tool should not be used in any current projects; the Worksheet tool covers all requirements.

So, to re-iterate: In ArchiCAD, it is recommended that a user should create (what are commonly known as) 'Details' using the Worksheet tool.

Two of the main differences between the two tools are listed below (extracted from ArchiCAD Help)
When transferring all or part of a source model view to a Worksheet window:

• Annotation elements and dimensions will, by default, appear in the resulting Worksheet, in addition to construction elements exploded into 2D components.
  In contrast, a Detail viewpoint created from the model will - by default - contain the 2D-only copies of construction elements only, without the source model's annotation/dimension elements.
  This is a major point of differentiation.


• The resulting Worksheet will, by default, have the same scale as the source.
  In contrast, a Detail is created, by default, at half the scale of the original.
  Of course, output scale (for placing on a view) is controlled at a later stage (for both Details and Worksheets), when saving a View of either.
  

The other major differentiation is that the Worksheet tool can be used to place Markers which link to other windows.
For example, in a section drawing, a worksheet marker could be placed to link to another section.

Further info on the Worksheet tool can be found at:
ArchiCAD-Wiki: Worksheets
ArchiCAD 16 Online Help
Also, another important tip from our website, on practical Worksheet usage (for creating 'Details') can be found here.