This video shows up to pair up phone with radio using Bluetooth. I don't have iDrive either and has the "BMW Professional Radio", exactly like the one shown in this YouTube video. .
Once paired, all ringtone, notification (e.g. email, GPS guidance...etc) can be heard via the car speakers. If using the Y-Cable for the iphone, you can control the Music function via the steering wheel controls. However, you cannot play other audio (e.g. Youtube, online radio) once Y-cable is connected. You have to use a 3.5mm to 3.5mm audio cable to play those type of audio.