I left the company earlier this year. The world outside of ATT is much happier and healthier, let me tell you.
I got the Key Contributor Award 3 out fo the last 5 years. My reviews and performance were always very high and I had great relationships with everyone.
When I decided I could no longer handle the crazy and telecommuting ("collaboration") BS, I let me manager know I was looking elsewhere. He didn't try to stop me. In fact, he told me I didn't owe ATT any loyalty because they sure didn't feel any loyalty toward me.
When I did actually put in my notice, barely anyone noticed. No one said anything about "what can we do to keep you?,etc. Which made me realize either I wasn't as important/valuable as I'd thought, or, middle management is under pressure to cut payroll/positions at all costs.
Regardless, I'm glad I got out of there on my own terms, and I feel for those still in that crazy house. Get out if you can.