This American Life two parts podcast, is probably one of the best accounts, of the challenges of changing large corporations, and how devastating poor leadership and culture can be for a huge company. Go and have a listen here
From the website: A car plant in Fremont California that might have saved the U.S. car industry. In 1984, General Motors and Toyota opened NUMMI as a joint venture. Toyota showed GM the secrets of its production system: How it made cars of much higher quality and much lower cost than GM achieved. Frank Langfitt explains why GM didn't learn the lessons—until it was too late.