Jain, Abel don't know who's next CEO: Buffett

Hints of 'Jain & Abel' in Berkshire's annual letter

Front-runners Ajit Jain nor Greg Abel don't know who will be Berkshire Hathaway's next CEO, Warren Buffett said Monday.

"The board has talked about it at every meeting for I don't know how many years. We have a precise plan in mind," Buffett told CNBC's "Squawk Box".

Jain and Abel, both long-time Berkshire Hathaway lieutenants, were named as possible successors to Buffett in Vice Chairman Charlie Munger's annual letter to shareholders. "When Charlie's letter came in, and he referenced Greg and Ajit, it was news to me that he was writing that. He's right, they're both very good," Buffett said.

Nevertheless, Buffett said in his annual letter to shareholders, which was released Saturday, he and the board have already agreed on who would carry the torch once his time comes. "In certain important respects, this person will do a better job than I am doing," Buffett said in his letter.

Currently, Abel is the chairman, president and CEO of Iowa-based Berkshire Hathaway Energy, while Jain runs the company's reinsurance division.

—CNBC's Javier David contributed to this report.