jim axelrod spoke with charles koch in a rare tv interview. >> reporter: koch industries, headquartered in a sprawling glass and granite campus in wichita is the second largest private company in the country. with more than 100,000 employees worldwide, the conglomerate refines up to 600,000 barrels of oil a day and produces everything from stainmaster carpets to electronic components for smartphones. own 84% of koch industries. forbes estimates their net worth at nearly $43 billion, each. but the sixth wealthiest man in the world still gets his lunch every day at the company cafeteria. although it's a bit more challenging after recent foot surgery. the 79-year-old ceo is at his desk each morning at 7:15 a.m. under the watchful eye of the family patriarch. this is your dad here? >> that's my dad, yeah. >> reporter: fred koch made his first fortune building refineries for stalin's soviet union and became a fervent anti-communist. >> it may be either a blessing or a curse. >> reporter: in his office, charles keeps a framed letter fred wrote to his first two sons when he took out an insuran