I've just been briefed about the remote layoff process that will start in the next month or so. You will receive a call from your Director, an HR rep, and an Outplacement specialist conferenced in. You will be told your position has been eliminated and that your severance agreement will be sent to you. Then the HR specialist will chime in and explain the severance package that will be sent out to you. You will then be asked asked if there are any questions at which point they will point you to the severance agreement that you will receive. You will then hear from the Outplacement specialist who will explain their 'transition services'.
You will then get your personal effects sent to you via UPS and will get another prelabled box for you to send back any GM-owned equipment. Upon receipt of these items, GM will then be able to start sending your severance checks, including the loan plus 5% that you have been providing in form of reduced paychecks.
That's what I know so far. I haven't received any details about who is going or when but that will come soon.