Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2025
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Acquisition of HarborOne Bancorp, Inc. Effective November 1, 2025, the Company completed its previously announced merger with HarborOne. In accordance with the merger agreement, each share of HarborOne common stock, at the holder’s election, was exchanged for either (i) 0.765 shares of Company common stock and cash lieu of any fractional share or (ii) $12.00 in cash, which was subject to allocation procedures to ensure that the total number of shares of HarborOne common stock that received the stock consideration represented between 75% and 85% of the total number of shares of HarborOne common stock outstanding immediately prior to the completion of the merger. The Company issued 26.9 million shares of its common stock and paid aggregate cash consideration of $74.6 million in the merger. HarborOne, a Massachusetts corporation, was a federally registered bank holding company headquartered in Brockton, Massachusetts. HarborOne Bank, a Massachusetts-chartered trust company formed in 1917, was a wholly-owned subsidiary of HarborOne that operated through a network of 30 full-service banking offices in Massachusetts and Rhode Island, and commercial lending offices in Boston, Massachusetts and Providence Rhode Island, with $5.5 billion in total assets and $4.3 billion in deposits as of October 31, 2025. The Company has not yet completed the purchase accounting due to the timing of the merger. Accordingly, the total purchase consideration and fair value of the assets and liabilities acquired, including goodwill and other intangible assets, is not yet available. Following the completion of the merger, the Company sold substantially all of the investment securities acquired through its merger with HarborOne. The amount of securities sold amounted to approximately $0.3 billion and no gain or loss was recognized upon sale as such securities had been recorded by the Company based upon the quoted sale prices in determination of the purchase accounting fair value adjustment. The Company used the proceeds from the sales to pay down wholesale funding.

Eastern Bankshares, Inc. 10-Q