4 iconic American CEOs are on the way out. Meet the nuts-and-bolts leaders taking their place.

Four iconic American CEOs are making way for a new generation of business leaders.

Warren Buffett, Bob Iger, and Doug McMillon have stepped down from the top jobs at Berkshire Hathaway, Disney, and Walmart, respectively.

Tim Cook has announced he’ll resign as Apple’s CEO in September.

Their successors aren’t household names, but they all share one common characteristic: they’re detail guys who know their companies inside out.

These nuts-and-bolts leaders pay attention to every little thing, understand the reality on the ground, and know how to get things done. “They’re having a moment,” Bill George — the former chairman and CEO of Medtronic and an executive education fellow at Harvard Business School — told Business Insider.

We take a closer look at each leader below and explore whether being a master of the details is enough to succeed.