Swoop is correct, the idle speed is controlled by the programming in the ECM and can only by changes by an engineer.

not sure it is possible
since these units are 'drive by wire' electronic throttle body's the idle is controlled by the ecm. Only if there is a physical idle screw the idle can only be changed by accessing the ecm via laptop and i do not think you can even do it then.
The question that comes to my mind is why do you feel the need to increase the idle? Are you having stalling issues? during steering or low speed/idle hydraulic operation? If so there are other issues causing that such as trim settings and/or possible vacuum leaks, something along those lines.