100% of the membership interests of Burlington Northern Santa Fe, LLC outstanding as of February 21, 2020 is held by National Indemnity Company, a wholly-owned subsidiary of Berkshire Hathaway Inc.
LC, BNSF is 100% owned by National Indemnity (10-K quoted above), and provides capital to the insurance operation; BNSF does not (on my view) benefit. Independent peer, UNP has no problem raising equally cheap debt capital.