The 66-year-old Arledge said nothing about retiring, however. He'll retain his title as ABC News chairman and will be consulted on major decisions. And on Friday, he was named senior vice president of ABC Inc.
ABC has been saying since March 1997 that Westin would succeed Arledge. That's when Arledge was elevated to chairman and Westin took over his old job as ABC News president. The two essentially have run the division in tandem since then.
An innovator in sports television, Arledge raised eyebrows when he took over the news division two decades ago. But he proved himself, launching Nightline with Ted Koppel, luring David Brinkley to Sunday morning television and establishing the newsmagazines PrimeTime Live and 20/20.
Until it was eclipsed by NBC last year, ABC's World News Tonight with Peter Jennings enjoyed a decade's run at the top of the evening news ratings.
The news division's influence has been slipping, with Good Morning America fading badly in the ratings and rumors floating that job or programming cutbacks are being considered.
As an assistant to ABC President Robert Iger, Arledge will work on companywide programming activities and new endeavors.
"Roone will go down in history as one of the true visionaries of our business," Iger said. "We're pleased to have the benefit of his counsel and insight going forward."
Westin assumes full control of ABC News effective Monday. Arledge said Westin "has innovative ideas, and our judgments have been almost identical in news matters. He will do a terrific job."
By David Bauder