Chevron Corporation is an American multinational energy corporation predominantly in oil and gas. The second-largest direct descendant of Standard Oil, and originally known as the Standard Oil Company of California (shortened to Socal or CalSo), it is headquartered in San Ramon, California, and active in more than 180 countries. Within oil and gas, Chevron is vertical integrated and is involved in hydrocarbon exploration, production, refining, marketing and transport, chemicals manufacturing and sales, and power generation.