Feb 8 (Reuters) - FirstEnergy beat Wall Street estimates for fourth-quarter profit on Thursday, as lower costs helped the electric utility offset muted demand for electricity due to milder-than-expected weather.

The Akron, Ohio-based firm, which serves more than six million customers across the Midwest and Mid-Atlantic regions, announced a $26 billion capital investment program from 2024 to 2028, focused on investments in the electric grid.

In the fourth-quarter, total operating expenses fell to $2.58 billion, from $2.78 billion, a year earlier.

However, total distribution deliveries decreased 1.3% year-over-year, and residential usage fell 4.9% as milder weather in service areas weighed on demand.

Analysts had flagged mild weather during the reporting period as a major headwind for utilities across the Midwest and Mid-Atlantic regions.

The company also forecast full-year earnings in the range of $1.5 billion to $1.62 billion, or $2.61 to $2.81 per share, compared with analysts' estimates of $1.59 billion, or $2.68 per share.

Peers NextEra Energy and Xcel Energy reported a rise in profit, for the quarter ended December 31, also benefiting from lower costs.

On an adjusted basis, the firm earned 62 cents per share in the fourth quarter, compared with analysts' average estimate of 59 cents per share, according to data from LSEG. (Reporting by Vallari Srivastava in Bengaluru; Editing by Tasim Zahid)