Exelon Corp. plans to split into two publicly traded companies, one for its regulated electric and gas utilities like ComEd and the other for its power generation assets like its nuclear power plants.

The announcement was made Wednesday as the Chicago-based company announced fourth-quarter earnings of $360 million, beating Wall Street estimates.

Exelon said separating the two companies will create the nation’s largest fully regulated transmission and distribution utility company. ComEd will remain part of the electricity and natural gas business that has operations in five states and more than 10 million customers. During the next four years, that company will invest $27 billion — including almost $6.6 billion this year alone — to continue modernizing the grid, Exelon executives said.

The nuclear, wind, solar, natural gas and hydroelectric assets will be spun off tax-free into a new company. Shareholders of Exelon Corp. will keep their Exelon stock and receive shares in the new company.

However, on a call with analysts Wednesday morning, Exelon executives said some uncertainties — including legislation in Illinois — could affect the future of the new power-generation company.

In August, Exelon said it will close two of its nuclear plants in Illinois — the Dresden plant in Grundy County and the Byron station southwest of Rockford — by fall 2021 without subsidies from the state. The announcement came a week after Pritzker laid out his principles for moving Illinois toward 100% carbon-free electricity by midcentury.

Earlier this month, during his combined budget and state of the state address Feb. 17, Pritzker said his legislative priorities for the year include “passing an energy bill that protects our nuclear fleet and builds up our wind and solar industries, protects the environment, puts consumers first and supports jobs.”

The public interest advocacy organization Illinois PIRG, which has called for ComEd to break from Exelon, said Wednesday’s announcement was good news for ComEd customers. However, it reiterated its position that the Illinois General Assembly needs to take action to right some of the policies associated with the alleged ComEd bribery scandal.

On a call with Wall Street analysts Wednesday morning, Exelon CEO Chris Crane was asked whether, between energy priorities identified by the Biden administration and Pritzker’s comments, he felt more or less optimistic than six months ago about getting financial help to keep nuclear facilities open.

“We’ve had a cloud in Illinois and that has slowed the process of the discussion,” Crane said. “As some look at ComEd and the nuclear plants being one and working to separate that. But also explaining not only the environmental benefits, but the community and the economic benefits that they serve, along with the reliability. In all of our jurisdictions that we have nuclear plants, I think that recognition is strong or becoming stronger.”

Crane and the existing management team will continue to lead the company until the separation is complete, which the company said should be in 2022′s first quarter. Additional details about senior management and company names will be released in coming months, Exelon said.

“Our industry is changing at a rapid pace and our customers expect us to continuously innovate to stay ahead of growing demand for clean energy, evolving business conditions and changing technology,” Crane said in a news release. “Now is the right time to take this step to best serve our customers, employees, community partners and shareholders. These are two strong, distinct businesses that will benefit from the strategic flexibility to focus on their unique customer, market and community priorities.”

The spinoff will require the approval of the Federal Energy Regulatory Commission, the Nuclear Regulatory Commission and the New York Public Service Commission.