David Koch, conservative donor and philanthropist, has died at age 79

Billionaire conservative icon David Koch has died at age 79, CBS News has confirmed, according to a source close to the Koch family. The New York resident was suffering from deteriorating health as of late, according to a letter Koch's older brother Charles Koch sent to company officials last summer.

He wrote at the time: "We are deeply saddened by this, as we miss David's insightful questions and his many contributions to Koch Industries."