NEW YORK (CNN/Money) - CMS Energy Corp. plans to sell its oil and gas exploration and production unit, CMS Oil and Gas Co., and exit the exploration and production business.

The company said Wednesday that the proceeds from the sale will help it meet its goal of raising $2.9 billion by the end of 2002 from what it calls "asset optimization." The company said it already has raised $2.4 billion toward that goal from other transactions.

The move is only the latest change for the integrated energy company, which is primarily an electric and natural gas utility. Last week it announced its chairman and CEO had left the company and that it would restate results due to questionable trades that inflated revenue by billions. The company faces an investigation by the Securities and Exchange Commission into some of its energy trades.

The oil and gas unit has operations in the Permian Basin of west Texas and overseas in Cameroon, the Republic of Congo, Colombia, Eritrea, Tunisia and Venezuela.

Shares of CMS (CMS: down $0.32 to $18.22, Research, Estimates) fell about 1 percent in early trading Wednesday following the pre-market announcement.