Description:The Daily Digit is $17 billion. The two biggest U.S. oil producers, Exxon Mobil and Chevron, reported higher-than-expected increases in quarterly profits, pocketing a combined $17 billion in earnings. Exxon Mobil, the world's largest publicly traded oil company, reported a 6% hike in quarterly profit on stronger results at its chemical and refining businesses. The company's profit in the fourth quarter was $9.95 billion compared with $9.4 billion a year earlier.(1:07)