American International Group Inc. on Monday announced that Peter Zaffino would become CEO of the insurer effective March 1, 2021, replacing Brian Duperreault who will become executive chairman.

In addition, the insurer said it will separate its life and retirement business from its property/casualty operations.

Mr. Zaffino, who previously worked with Mr. Duperreault at Marsh & McLennan Cos. Inc., joined AIG a few weeks after Mr. Duperreault was brought in to turn the insurer around in 2017. He was promoted to president of the insurer earlier this year.

“Peter has been instrumental in the significant turnaround and transformation at AIG, and his vision, determination and pursuit of excellence will help ensure the company’s future success,” Mr. Duperreault said in a statement.

Separately, AIG said it had decided to separate its life and retirement business after a review of its structure.

Douglas M. Steenland, chairman of AIG, who will become lead director when Mr. Duperreault changes roles, said, “AIG’s directors are confident that a separation of Life & Retirement from AIG will create value for shareholders and benefit all stakeholders.”

According to the AIG statement: “No assurance can be given regarding the form that a separation transaction may take or the specific terms or timing thereof, or that a separation will in fact occur.”

AIG’s life and retirement business includes its individual retirement, group retirement, life insurance and institutional markets businesses and accounted for about 34% of the company’s $49.7 billion in 2019 revenue, according to AIG’s most recent annual report.

The announcement that it will separate its businesses comes four years after activist investor Carl Icahn called for the breakup of AIG into three separate companies.

Mr. Icahn backed off his demands after Mr. Duperreault was appointed CEO and later sold his shares in the insurer.

Meanwhile, also on Monday, AIG announced that its third-quarter catastrophe losses totaled $790 million before tax, including $185 million in COVID-19-related claims. The $605 million in other catastrophe claims were from windstorm and wildfire losses, the statement said.