Pros
As it usually occurs in large corporations, everything heavily depends on the subdepartment you are working at. Being an employee of internal web development, I was quite happy with the flexibility and autonomy I was given. This resulted in an almost free choice of technologies, approaches and methodologies if the problems were solved in the reasonable and appropriate way. The people I worked with were really great.
Cons
The contras are direct implications of pros. The development of technical competences in such a team are limited by the highest level of team leader. If the team does not constantly learn and follow new progressive approaches, it is possible to loose the track of reality after spending several years there. In particular, only basic IT processes were used. Another important aspect is people. Although it is possible to find a really great team or environment, in a large company this often is determined by chance, so definitely makes sense to know more about the particular team before joining it. Career opportunities were quite limited.