What companies does ATT own?

AT&T owns:

AT&T Alascomm

AT&T Communications

AT&T Laboritories

AT&T Communications owns Comcast, and many, many of the baby-Bells; including SBC Communications. Too many to list. Go to wikipedia for a list.

But, they do NOT own T-Mobile (owned by Duetsch Telecomm) or Sprint (who did by Nextel.)