They are separate parts. The throttle actuator is nothing more than a large servo not unlike an RC car, but with a CAN interface. It uses a linkage arm to operate the throttle body butterflies.
The idle control is similar, but has a valve built in to control airflow through it.
Look here for part numbers:
http://realoem.com/bmw/partgrp.do?mo...id=52128&hg=13
Idle actuator is
http://realoem.com/bmw/showparts.do?...41&hg=13&fg=15
Throttle actuator is
http://realoem.com/bmw/showparts.do?...45&hg=13&fg=15