Warren Buffett's Berkshire Hathaway is buying a Phillips 66 subsidiary with approximately $1.4 billion worth of the oil company's own shares.

Berkshire reported owning about 27.1 million shares of Phillips 66 at the end of September. At today's closing price of $74.72, that stake is worth just over $2 billion.

A Phillips 66 filing said it will be getting approximately 19 million of those shares from Berkshire in exchange for Phillips Specialty Products, a unit that "focuses on the science of drag reduction, specializing in maximizing the flow potential of pipelines."