OMAHA, Neb. (AP) — Berkshire Hathaway is buying Occidental Petroleum's chemical division for $9.7 billion in what may be the last big acquisition involving the consummate dealmaker, Warren Buffett. Warren Buffett wasn’t mentioned anywhere in materials released by Berkshire Hathaway discussing the deal Thursday, potentially signaling a passing of the torch to Vice Chair Greg Abel, to whom Buffett will hand the CEO title in January. But given the relationship that Buffett has with Occidental CEO Vicki Hollub ...