Initially Buffett started out as pretty much an arbitrageur, he focused on companies selling below their liquidation value. This was all from learning under Benjamin Graham. So if you look at his partnership years, he would often invest in companies where they had hidden assets.

Sanborn Map company sold maps, but they also had an investment portfolio that dwarfed their market cap. So he had them sell it off. He did a lot of cigar butts like that. Back then, Buffett was pretty pushy. He would do whatever it took to acquire all the stock of companies and would sack the management teams and replace them with others. At one point an entire town in Dempster protested against him.

Then he met Charlie Munger and Munger got him to start focusing on acquiring good businesses that had franchise values. See's Candy is the best example. So he looked for companies with sustainable competitive advantages and high returns on invested capital. So he started to buy your good businesses run by great entrepreneurs with little actual control. The only thing he would ask is if they could not meet an internal hurdle for ROIC (return on invested capital) that they give excess capital for him to redeploy.

Now, if you look at what Buffett has been doing, he's continued to evolve a bit. He seems much more focused on buying utility-like businesses. MidAmerican and Burlington Northern exemplify this. They don't throw off cash that can be redeployed elsewhere like the previous Berkshire deals. At the same time though, they potentially can be around for the next 50 years and increase prices to make up for inflation.

These deals are probably going to continue. Buffett must realize that his 3 replacements wont be as good at allocating capital, so he will need to find businesses that are great but also utilize a lot of cash. That would reduce the burden on his CIO replacements.