Lowrey will continue to be the chairman for 18 months.

Sullivan said he wants to "expand Prudential's position as a leader in investing, insurance and retirement security."

Andrew Sullivan: Sullivan started out in insurance as an executive at Cigna, and he was an executive at CareFirst, a Blue Cross Blue Shield carrier that serves Maryland and the District of Columbia, from 2009 through 2011. He moved over to Prudential's disability insurance business in 2011. Early on, he wrote articles for trade journals about topics such as absence management and return-to-work programs.

By 2017, he was running the group insurance and retirement businesses. From 2019 through early 2023, he ran all of the U.S. businesses. He took charge of the international businesses in early 2023.

Prudential's U.S. benefits operations: Prudential generated $2.5 billion in net income on $54 billion in revenue in 2023.

The group insurance business produced $66 million of the operating income and $1.5 billion of the revenue.

Related: Employer-provided short-term, long-term disability benefits at record highs

The U.S. retirement businesses produced $914 million in operating income on $4.3 billion in revenue.

Prudential made big news in both the health insurance market and the retirement benefits market in September. The company entered the medical stop-loss insurance market that month. Stop-loss programs provide insurance for employers' self-funded benefit plans.

Prudential also announced a huge group annuity sale in September. IBM plans to use the annuity to transfer $6 billion in defined benefit pension plan risk to Prudential.

The future: One question is whether Sullivan's experience in benefits, and Prudential's increased focus on lower-risk, easier-to-reprice and easier-to-hedge products, could make the company a potential buyer of stand-alone benefits companies, like Unum, or the benefits arms of companies like Lincoln Financial.

His experience as an executive at Cigna and CareFirst during the years when the Affordable Care Act was being drafted and implemented may also have given him broad, deep knowledge of how health system change happens.

Prudential sold its U.S. health insurance operations to Aetna in 1998, but it still offers health insurance in Indonesia, and it sells supplemental health insurance products, such as critical illness insurance, through associations in the United States. It could be in a good position to return to the U.S. major medical insurance market, if it ever wanted to do that.