The deal entails buying out the company's chief executive, Richard Kinder, for $107.50 per share -- totaling $15 billion in cash -- as well as assuming $7 billion of corporate debt.
The investor group includes banking giant Goldman Sachs Capital Partners, insurers American International Group, and private equity firms Carlyle Group and Riverstone Holdings.
The company said Kinder will continue as its chief executive and reinvest all of his 24 million shares in Kinder Morgan.
"This buyout reflects the confidence that senior management and the sponsors have in the potential of Kinder Morgan Energy Partners. KMI's ownership of the general partner of, and other partnership interests in, KMP represents KMI's largest asset," Kinder said in a news release.