Immelt expects the plastics business to be sold in the second half of this year. The business is expected to fetch at least $10 billion.
Analysts see private-equity buyers as well as chemicals giants such as BASF, Dow Chemical and Saudi Arabia's Saudi Basic Industries as likely buyers.
Although the business has faced challenges, "there are a lot of people for whom plastics is a good asset," Immelt said.
Some industry analysts were surprised by the quick pace of GE's recent deals.
"Do I like doing three deals this big, this quickly? I don't," Immelt said. "But they are all on strategy, and they all kind of happen as they happen....These were just additional steps along the way of making it a better company."
Earlier, GE reported higher fourth-quarter earnings in line with analyst estimates.
Imment also commented on several other topics.
On the GE stock price:
"We trade at an 18-times earnings," Immelt said, explaining that level is a "slight premium" to the market.
"There's nothing not to like about the stock today," he said. "When I got to GE five years ago, GE's (price-to-earnings ratio) was the same as Google's is today. That's probably not sustainable for GE, and probably not sustainable for a lot of companies during that time period."
On why someone should hold GE stock:
"The best days are ahead. This is a better company today than it was five years ago by far...The long-term growth rate has increased, the return of total capital is expanding, margin rates are expanding...We've doubled our organic growth within the company, and look, that's all ahead of investors in the future."
On future growth:
"The good news for a company like GE is: the developing markets are booming and that's going to continue."
On CEO compensation:
"Transparency is key," he said. "In my belief, and again it's just my belief, people shouldn't have contracts....I think you ought to be in the same position that every other person in the company is. You've got to bring it every day, and if you don't bring it, you shouldn't have a contract that defines how much you get if you fail. That's my own philosophy. You have to have a lot at risk."
Immelt said he wouldn't want compensation to be regulated. However, he said, it could happen if businesses don't reform the situation on their own.
As for himself, Immelt said: "I value my own reputation more than I value the money I make."