If you are worried about ATT layoffs, then take advantage of the system. I would make sure to finish your ungrad/grad if you haven’t complete it yet.
For non-bargained employees, if you leave on your own you have to pay off the last two years of what ATT reimbursed, but if you are laid off you pay nothing. There is life after ATT just take advantage of the resources you have.
I recently volunteered for a surplus package and now I only have one semester left to complete my undergrad. My new job only covers $1500 a year versus ATTs $8250, so I am glad that I finished most of my school while I was with ATT.
They also have other resources for free like the Udacity courses(I’ve heard mixed reviews) but at the very least it does give you a starting point for life after.
For union employee I would definitely take advantage of tuition reimbursement, you literally get you education paid for and can leave right after.