The credit card magnate turned mega-donor built one of the country's largest rural health systems.

T. Denny Sanford, First Premier Bank owner and South Dakota's richest has died at 90. Gov. Larry Rhoden praised his legacy. A cause of death was not announced.

The credit card magnate turned mega-donor built one of the country's largest rural health systems.

Denny Sanford died at 90 after donating more than $4 billion during his lifetime, leaving behind a legacy of philanthropy and controversy.

T. Denny Sanford, a philanthropist who donated billions toward healthcare and for whom the 58-hospital Sanford Health is named, died July 18 at the age of 90. | The Midwest…