Cliffs would purchase all of U.S. Steel for all cash and then sell off the Big River Steel subsidiary to Nucor, sources told CNBC's David Faber. U.S. Steel's headquarters would remain in Pittsburgh under the deal.

Cleveland-Cliffs is discussing joining with Nucor on a possible bid for U.S. Steel that is still likely months away from happening, according to people familiar with the matter. U.S. Steel had planned to sell itself to Japanese steelmaker Nippon Steel,

Joint bid for U.S. Steel assets would have Cleveland-Cliffs acquiring blast furnace mills and Nucor taking over Big River Steel, according to CNBC and Bloomberg.