CONTRACT = Job Security & Just Cause

Comcast Employment Policy

The contents of the Comcast Employee Handbook are not intended to create an express or implied contract or other legally enforceable promise between you and the company and you may not rely on it as such.

Your employment relationship with Comcast is "at will" and nothing in the Employee Handbook is intended to extend or guarantee employment with the Company at any time for any reason. Just as you have the right to terminate your employment with the Company at any time for any reason, the company reserves the right to terminate your employment relationship at any time for any reason. Nothing stated in the Employee Handbook shall be construed as impairing or altering your rights or the company's rights in anyway.

The indivual provisions of the Employee Handbook are simply guidlines, and Comcast reserves sole discretion to interpert them. Comcast also reserves the right to change, delete, suspend,discontinue,or otherwise revise the Employee Handbook at any time for any reason , with or without notice.

The language above is taken from a copy of a Comcast Employee Handbook

With an IBEW contract , the terms and conditions of employment  would be mutually agreed upon and cannot be unilaterally changed by Comcast without negotiating those changes with the employees.