AutoDesk Invertor is the right program in case you need or want to export .idw drawings (Autodesk Inventor drawing) to common DXF CAD file. It is likely that idw to dxf conversion can be achieved using dedicated export function or by simple re-saving (File ► Save as..)
Unfortunately, we have no information about any other software that can directly convert idw to dxf or how to achieve this conversion without Inventor.