AOL Time Warner CEO Jerry Levin will leave the media giant he helped create, the company announced on Wednesday.

Levin’s unexpected departure was just a part of the senior management succession plan the company unveiled. The six-month transition plan includes current Co-COO Richard Parsons becoming CEO, Co-COO Robert Pittman becoming the sole COO (and now reporting to Parsons), Steve Case continuing to have an active role as Chairman and Levin retiring at the time of AOLTW’s annual meeting in May.

One of the titans of the media business, Levin guided the growth of Time Warner that led to its acquisition by No. 1 Internet service provider America Online last year.

"After spending virtually my entire career at this great company, it is obviously a major decision for me to begin this succession process," said Levin. "But this is a step that I have been thinking about for some time and whose time has come. Given that we are almost a full year into the merger and that an outstanding management team is now in place at the company, I am convinced that AOL Time Warner should begin an orderly transition to a new era of leadership."

Case, who will continue to serve as chairman, lauded Levin's "vision and commitment over the past three decades."

"All of us at AOL Time Warner and the industry at large owe Jerry Levin a huge debt of gratitude for his role in building this great company," Case said. "Part of Jerry's enormous legacy is AOL Time Warner's breadth of management talent and unmatched track record of innovation. In Dick Parsons and Bob Pittman, this company has two of the most extraordinary business leaders to be found anywhere. They have been instrumental in pulling together the various units of our company, streamlining our operations and pursuing many growth opportunities for the future. Dick and Bob offer us a powerful and complementary combination of intellect, business acumen and strategic perspective, and I am looking forward to working with them closely in the years ahead."

Said Parsons: "As the world knows, if it were not for Jerry Levin, AOL Time Warner would not be in the position it is today as the world's preeminent media and communications company. Although I will miss him deeply, I am happy for him as a friend because I know that retirement is something that he has been considering for some time. Steve, Bob and I will work hand-in-hand in a full partnership to build on Jerry's legacy. We will continue to use the unique collection of assets he assembled to dramatically enhance the lives of our customers with consistently high-quality content and services."

To which Pittman added: "I've worked with Jerry off and on for over a decade and his contributions to this company and to the entire media industry are incalculable. The growth strategy that he set in motion over the past year will continue to benefit AOL Time Warner and its shareholders for years to come."

"Dick and Bob's new roles play to their strengths," Levin added. "They've worked seamlessly together in helping bring the company to this point, and they'll continue to make a great team."

In early trading on Wednesday morning, shares of AOL Time Warner fell 30 cents to $34.45.