More from Valero's (NYSE:VLO) Q4 results: Operating income was $1.6B vs. $167M a year ago due to...

More from Valero's (NYSE:VLO) Q4 results: Operating income was $1.6B vs. $167M a year ago due to higher refining throughput margins plus lower refining operating expenses. Replaced all imported light sweet crude used at its Gulf Coast and Memphis refineries with cheaper North American crude. Idled three of its 10 ethanol production facilities due to high corn prices and high ethanol inventories. VLO +7.7% premarket.