At Berkshire Hathaway, 2019 was another good year — and an opportunity for its leader, Warren Buffett, to prepare his company for life without him.

In his latest letter to investors, published on Saturday morning, the billionaire largely praised the performance of his $566 billion conglomerate, whose portfolio includes the insurer Geico, the chemical maker Lubrizol, Fruit of the Loom underwear and more.

“Our unrivaled mountain of capital, abundance of cash and a huge and diverse stream of non-insurance earnings allow us far more investment flexibility than is generally available to other companies in the industry,” he wrote.

The annual report was accompanied by the latest assessment of Berkshire’s financial health: The company reported $29 billion in net income for the fourth quarter of 2019, and $81.4 billion for last year overall. Operating earnings, Mr. Buffett’s preferred measure of financial performance, declined slightly last year from 2018, to $24 billion.