A question about corporate officers?

I just read: "Randall Stephenson, President, CEO, and Chairman of the Board of AT&T". Obviously, the guy can't put in 120 hours a week doing all these jobs, so how does this work?

OK, the CoB is not a full time job, so set that aside. Stephenson is left with the Pres and CEO jobs. Does he have two ball caps with those labels, and swap them as he changes what he's doing? How does he know when he's doing CEO stuff and when it's President-y stuff?

How many companies have different people in the CEO and President positions, vs. having one person do both? It eems that a really big company like AT&T could use two people to run it, and yet it's always the mega-companies that do the cap-switching thing. Is there a legal requirement that all corporations have (at least on paper) these offices, but they don't necessarily have the work done by different people?

Both President and CEO sound like they would have the same job description - "Run the company." So what is with this common "fiction" about corporate executive staffing? And by the way, does Stephenson really have to work twice as hard? Does he get a separate salary for each? Or is this just an ego sop?