Zucker to step down from NBC, CNN chief replaced

"Comcast will be a great new steward, just as GE (General Electric) has been, and they deserve the chance to implement their own vision," Zucker said. "I am proud that they will inherit a company in very good shape, with almost every one of our divisions enjoying their best year ever."

In another shakeup at the top of a media company on Friday, Time Warner announced the replacement of Jon Klein as head of CNN's U.S. division with Ken Lautz, who runs the sister channel HLN. Klein led CNN for six years but lost ground in the ratings against more opinion-centered content from Fox News and MSNBC.