The good:
Better than average compensation
Generous bonuses for top performers in profitable business units
Company offers tuition reimbursement
Combined defined benefit and 401(k) retirement plans
Many internal training opportunities
Somewhat entrepreneurial
Some of the best HR policies I've ever seen
One of the few places left where it is still possible to spend an entire career from college to retirement
The bad:
External training is the first thing cut from budgets. It's very difficult to expand your technical knowledge unless it's tied to a specific project.
Easy to get lost in the crowd, incompetents and slackers can slide for years and lower managers are afraid they'll lose head count if they get rid of them. Other employees have to work harder and put in more hours to make up for the incompetent slacker. Many find their way into lower management eventually.
Very political environment. Befriend a Vice President and you've got it made. Upset one and your life will truly suck. Upset one you previously befriended by telling him/her what s/he doesn't want to hear even if it's the truth and work becomes a living hell.
The bureaucracy can rival the former Soviet Government, but make the right connections and you'll get what you need/want.