The deal, under which KKR could buy between 20% and 25% of Enilive, is part of Eni's satellite strategy to develop separate units focused on specific businesses and make them become financially independent.
"The strong interest shown in this period by leading institutional financial investors could lead to the subsequent sale of a further stake of up to 10% of Enilive," the Italian energy group said in a statement.
In December Swiss fund Energy Infrastructure Partners (EIP) bought a minority stake in Eni's retail and renewable unit Plenitude in a deal that valued the company around 10 billion euros.