momently we are having an energy efficiency audit in public institucions. Mostly (up to 95%) using computers from Dell. For the evaluation of the datas we need the idle consumption of the computers, displays, monitors, printers, switches...etc. Does it give an overview (maybe excel sheet) about the idle consumption of each type of device?

I have only seen this information for Dell servers. I suggest you get a "Kill-A-Watt" or "Watts Up" electricity usage monitor/meter and take your own measurements on the different types of equipment and models that you need to audit. Hopefully there is a somewhat strict standard on what has been purchased for those public institutions so that you don't have a gazillion models to take your standardized idle measurement on.