Where did the term Cool million come from?

The term "cool million" is believed to have originated in the United States during the mid-20th century, often used to describe a million dollars in a casual or nonchalant manner. The Word "cool" conveys a sense of calmness or detachment, implying that having a million dollars is an impressive yet effortless achievement. It has since entered popular culture, representing wealth and success in a laid-back context.