Ted Turner, a mercurial tycoon and gadfly visionary whose “superstation” TBS was a cornerstone of cable TV’s early success, whose 24-hour news channel CNN revolutionized TV journalism, and whose sprawling legacy encompassed conservation, philanthropy and professional sports, died Wednesday at his home near Tallahassee. He was 87.

His death was confirmed by Phillip Evans, a spokesman for Turner Enterprises. Mr. Turner revealed in 2018 that he had Lewy body dementia, a progressive brain disorder.