Astor, recently the center of a highly publicized legal dispute over her care, died of pneumonia at her suburban estate, family lawyer Kenneth Warner said.
Although a legendary figure in New York City and feted with a famous gala on her 100th birthday in March 2002, Astor was mostly interested in putting the fortune that husband, Vincent Astor, left to use where it would do the most to alleviate human misery.
Her efforts won her a Presidential Medal of Freedom, the nation's highest civilian honor, in 1998.