We’ve taken a look at some of the nation’s big givers. Some of them you may know — others you may not.
President Barack Obama presents a 2010 Presidential Medal of Freedom to Warren Buffett on Feb. 15, 2011, during a ceremony in the East Room of the White House in Washington. Buffett, a billionaire who pledged the bulk of his fortune to philanthropy, has said the need for charitable giving is unending. Carolyn Kaster/AP Buy Photo