In 1911, the federal government broke Standard Oil into several pieces under the Sherman Antitrust Act. One of those pieces, Standard Oil Co. (California), went on to become Chevron. It became part of the "Seven Sisters", which dominated the world oil industry in the early 20th century. In 1926, the company changed its name to Standard Oil Co. of California (SOCAL). By the terms of the breakup of Standard Oil, at first Standard of California could use the Standard name only within its original geographic area of the Pacific coast states, plus Nevada and Arizona; outside that area, it had to use another name. Today Chevron is the owner of the Standard Oil trademark in 16 states in the western and southeastern U.S. To maintain ownership of the mark, the company owns and operates one Standard-branded Chevron station in each state of the area, although its status in Kentucky is unclear after Chevron withdrew retail sales from Kentucky in July 2010.The Chevron name came into use for some of its retail products in the 1930s. The name Calso was also used from 1946 to 1955 in states outside its native West Coast territory.Standard Oil Company of California ranked 75th among United States corporations in the value of World War II military production contracts.In 1933, Saudi Arabia granted California Standard a concession to find oil, which led to the discovery of oil in 1938. In 1948, California Standard discovered the world's largest oil field in Saudi Arabia, Ghawar Field. California Standard's subsidiary, California-Arabian Standard Oil Company, grew over the years and became the Arabian American Oil Company (ARAMCO) in 1944. In 1973, the Saudi government began buying into ARAMCO. By 1980, the company was entirely owned by the Saudis, and in 1988, its name was changed to Saudi Arabian Oil Company—Saudi Aramco.Standard Oil of California and Gulf Oil merged in 1984, which was the largest merger in history at that time. To comply with U.S. antitrust law, California Standard divested many of Gulf's operating subsidiaries, and sold some Gulf stations and a refinery in the eastern United States. (The refinery is currently owned by Sunoco.) Among the assets sold off were Gulf's retail outlets in Gulf's home market of Pittsburgh, where Chevron lacks a retail presence but does retain a regional headquarters there as of 2013, partially for Marcellus Shale-related drilling. The same year, Standard Oil of California also took the opportunity to change its legal name to Chevron Corporation, since it had already been using the well-known "Chevron" retail brand name for decades. Chevron would sell the Gulf Oil trademarks for the entire U.S. to Cumberland Farms, the parent company of Gulf Oil LP, in 2010 after Cumberland Farms had a license to the Gulf trademark in the Northeastern United States since 1986.In 1996 Chevron transferred its natural gas gathering, operating and marketing operation to NGC Corporation (later Dynegy) in exchange for a roughly 25% equity stake in NGC.  In a merger completed February 1, 2000, Illinova Corp. became a wholly owned subsidiary of Dynegy Inc. and Chevron's stake increased up to 28%.  However, in May 2007 Chevron sold its stake in the company for approximately $985 million, resulting in a gain of $680 million.

Question: What did the California Standard do to comply with U.S antitrust law?
Answer: divested many of Gulf's operating subsidiaries, and sold some Gulf stations and a refinery in the eastern United States