v3.26.1
Schedule H, Line 4i – Schedule of Assets (Held At End of Year) (Details) - EBP 002
12 Months Ended
Dec. 31, 2025
USD ($)
EBP, Schedule of Asset Held for Investment [Line Items]  
Entity tax identification number 04-3067724
Plan number 002
Notes receivable from participants, current value $ 5,237,113
Total investment assets $ 380,684,168
Minimum  
EBP, Schedule of Asset Held for Investment [Line Items]  
Participant loan interest rate 4.25%
Maximum  
EBP, Schedule of Asset Held for Investment [Line Items]  
Participant loan interest rate 9.50%
Investment, Identifier [Axis]: Artisan High Income Instl  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value $ 1,283,521
Investment, Identifier [Axis]: Capital Group Europacific Growth  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 8,340,984
Investment, Identifier [Axis]: Conestoga Small Cap Institutional  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 12,344,317
Investment, Identifier [Axis]: DFA Intl Sustainability Core 1  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 3,507,316
Investment, Identifier [Axis]: DFA U.S. Small Cap Value Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 6,312,611
Investment, Identifier [Axis]: DFA U.S. Sustainability Core 1  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 4,291,183
Investment, Identifier [Axis]: Dodge & Cox Income Fund X  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 4,100,840
Investment, Identifier [Axis]: Dodge & Cox Stock Fund Class X  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 12,001,891
Investment, Identifier [Axis]: Eastern Bankshares, Inc. Common Stock  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 45,194,604
Investment, Identifier [Axis]: Fidelity Blue Chip Growth K6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 30,804,919
Investment, Identifier [Axis]: JP Morgan Emerging Markets Equity R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 4,096,325
Investment, Identifier [Axis]: State Street Russell Small/Mid Index  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 9,483,787
Investment, Identifier [Axis]: Vanguard Developed Markets Index Admiral  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 7,734,247
Investment, Identifier [Axis]: Vanguard Institutional Index Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 82,857,352
Investment, Identifier [Axis]: Vanguard Short Term Corporate Bd Idx Adm  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 2,674,265
Investment, Identifier [Axis]: Vanguard Short-Term Treasury Idx Admiral  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 2,552,816
Investment, Identifier [Axis]: Vanguard Target Retirement 2020  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 3,754,773
Investment, Identifier [Axis]: Vanguard Target Retirement 2025  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 7,671,811
Investment, Identifier [Axis]: Vanguard Target Retirement 2030  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 24,010,286
Investment, Identifier [Axis]: Vanguard Target Retirement 2035  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 16,876,699
Investment, Identifier [Axis]: Vanguard Target Retirement 2040  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 15,408,488
Investment, Identifier [Axis]: Vanguard Target Retirement 2045  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 11,639,017
Investment, Identifier [Axis]: Vanguard Target Retirement 2050  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 14,085,430
Investment, Identifier [Axis]: Vanguard Target Retirement 2055  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 6,501,008
Investment, Identifier [Axis]: Vanguard Target Retirement 2060  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 2,844,219
Investment, Identifier [Axis]: Vanguard Target Retirement 2065  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 2,338,064
Investment, Identifier [Axis]: Vanguard Target Retirement Income  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 4,061,225
Investment, Identifier [Axis]: Vanguard Total Bond Market Index Inst  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value 11,859,081
Investment, Identifier [Axis]: Vanguard Treasury Money Mkt  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investment, current value $ 16,815,976