MetLife has rallied 13 percent since Trump's victory in November. Results were released after the close of regular trading.

Kandarian is preparing to spin off a U.S. retail business that sells life insurance and annuities to individuals. The first step of that separation, which was motivated partly by the prospect of tougher capital rules, could take place in the first half of this year, the CEO said in November.

Legal clash

MetLife sued the Financial Stability Oversight Council in 2015 after the insurer was labeled too big to fail, a tag that could bring tighter capital requirements and stricter oversight. The company won a court challenge in March that struck down that label. The U.S. appealed.

The CEO has also been cutting jobs to counter years of low interest rates. He announced a plan in August to reduce annual expenses by about $1 billion by the end of 2019.

Based on generally accepted accounting principles, the company posted a fourth-quarter net loss of $2.09 billion. The figure was fueled by changes in the value of derivatives, which the insurer uses to guard against fluctuations in interest rates, currencies and stock prices.

"While rising interest rates are good for MetLife's businesses, they reduced the carrying value of our derivatives book and produced a quarterly net loss on a GAAP basis," Kandarian said.

Related: MetLife judge found fault with FSOC too-big-to-fail review

Book value, a measure of assets minus liabilities, dropped to $59.56 a share as of Dec. 31 from $69.35 as of Sept. 30. MetLife reported operating return on equity of 10 percent in the fourth quarter, compared with 9.7 percent during the same period a year earlier. Full-year ROE dropped to 8.9 percent from 9.7 percent.

Fourth-quarter investment income gained 2.5 percent to $5.04 billion. Stronger private equity returns in recent months have helped counter pressure from more volatile hedge-fund holdings, which MetLife is seeking to exit.

Brighthouse, the U.S. retail division slated for separation, posted operating earnings that fell 15 percent to $330 million from the same period a year earlier due to lower separate-account fees and a change in life reserves. That business, led by Eric Steigerwalt, reported that sales of annuities and life insurance slumped 36 percent.

To keep a U.S. P&C operation

MetLife will keep a U.S. operation that includes property-casualty insurance, the retirement and income-solutions division and a group offering coverage through employers. Profit at that U.S. segment climbed 19 percent to $516 million from a year earlier, partly due to growth in group benefits and retirement and income solutions

Operating earnings in Asia climbed 22 percent to $354 million. The Europe, Middle East and Africa operations had a profit of $72 million compared with $54 million a year earlier, helped by better results in employee benefits and accident-and-health coverage.

Earnings at the Latin American operation fell 22 percent to $122 million, partly due to higher expenses. The year-earlier period had a one-time tax benefit in the region.

Last year, MetLife rearranged its businesses as it prepared for the separation of Brighthouse. The insurer lumped its long-term care business and a reinsurance deal tied to a previous Japan joint venture into a new unit called MetLife Holdings. Profit at that division slumped 25 percent to $199 million.