ExxonMobil and Chevron reported second-quarter profits that more than quadrupled as the Iran war pushed oil prices higher. The two oil giants posted combined earnings of over $26 billion for the quarter, a surge of more than 300% compared with the same period last year. Both companies announced the results on Friday. Rather than sharply increasing share buybacks, they steered the windfall into paying down debt. That decision signals that Big Oil remains cautious about how long the war-driven price rally will last. With crude prices elevated by the conflict in Iran, profits jumped sharply, giving the companies extra cash to strengthen their balance sheets. By choosing debt reduction over larger shareholder returns, Exxon and Chevron are preparing for the possibility that oil prices could fall again once the war-driven rally fades.