Ex-VP Cheney wrote contingency resignation letter in 2001

In a "60 Minutes" interview, former Vice President Dick Cheney spoke to Dr. Sanjay Gupta about his 35-year struggle with heart disease. He revealed he wrote a letter of resignation in 2001 in case he was unable to complete the job due to his health. For Dr. Gupta's complete interview, watch "60 Minutes" on CBS, this Sunday.