| Submission | Feb. 24, 2025 |
| Submission [Line Items] | |
| Central Index Key | 0000013372 |
| Registrant Name | NSTAR ELECTRIC CO |
| Registration File Number | 333-264278-02 |
| Form Type | S-3 |
| Submission Type | 424B5 |
| Fee Exhibit Type | EX-FILING FEES |
| Offerings | Feb. 24, 2025 USD ($) |
| Offering: 1 | |
| Offering: | |
| Fee Previously Paid | false |
| Rule 457(r) | true |
| Security Type | Debt |
| Security Class Title | 4.85% Debentures, Due 2030 |
| Maximum Aggregate Offering Price | $ 399,256,000 |
| Fee Rate | 0.01531% |
| Amount of Registration Fee | $ 61,126.09 |
| Offering Note | |
| Offering: 2 | |
| Offering: | |
| Fee Previously Paid | false |
| Rule 457(r) | true |
| Security Type | Debt |
| Security Class Title | 5.20% Debentures, Due 2035 |
| Maximum Aggregate Offering Price | $ 398,268,000 |
| Fee Rate | 0.01531% |
| Amount of Registration Fee | $ 60,974.83 |
| Offering Note |
| Fees Summary | Feb. 24, 2025 USD ($) shares |
| Fees Summary [Line Items] | |
| Total Offering | $ 797,524,000 |
| Previously Paid Amount | 0 |
| Total Fee Amount | 122,100.92 |
| Total Offset Amount | $ 0 |
| Narrative Disclosure | |
| Net Fee | $ 122,100.92 |
| Narrative - Max Aggregate Offering Amount | shares | 797,524,000 |
| Final Prospectus | true |
