Sandy Weill still has the checkbook he used in 1967 to make the first donations of the Weill Family Foundation. One was for $10, to his temple. The biggest was for $100. Since then, he and his wife Joan have given away more than $1 billion, often in much larger amounts: $250 million to the medical school at Cornell University in 2007 and $185 million to start a neuroscience institute at University of California San Francisco in 2016. And they’re not done yet, said Weill, 86, with gifts coming in areas new to them, like artificial intelligence and big data.