Marathon Oil Corp., a $58.5 billion oil and natural gas producer based in Houston, named Michael Stewart controller and vice president of accounting. He succeeds vice president of accounting Albert Adkins, who is retiring after 30 years with Marathon Oil. Most recently, Stewart, 48, was Marathon’s controller after serving as director of internal audit since 2002. Previously, he held various positions at Marathon Oil, including director of corporate staff for USX Corp., Marathon’s former holding company. Before he joined the company in 1985, Stewart worked at KPMG LLP as a tax specialist. He started his career in 1979 as an internal auditor for Exxon Mobil Corp.