Chevron says its quarterly profit fell 5 percent in the first quarter as oil prices slipped.
Exxon Mobil's quarterly profit edged up, as the world's largest publicly traded oil company's results were helped by higher earnings in its chemicals business.
Last year was the second most extreme weather year in U.S. history, and the corporate world is at last starting to realize that climate change could cost it a fortune.
A sharp decline in the price of oil this month is making gasoline cheaper at a time of year when it typically gets more expensive.
Oil-services company Halliburton says it lost $18 million in the first quarter on litigation-related charges related to the 2010 Gulf of Mexico oil spill.