SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Millions |
6 Months Ended | |
|---|---|---|
|
Jun. 30, 2025
USD ($)
customer
regulatedUtility
|
Dec. 31, 2024
USD ($)
|
|
| Summary of Accounting Policies [Line Items] | ||
| Number of electric, natural gas and water customers | customer | 4,600,000 | |
| Energy Relief Fund - Merrimack Valley Programs | ||
| Summary of Accounting Policies [Line Items] | ||
| Restricted cash, current | $ 20.0 | $ 20.0 |
| Restricted cash, noncurrent | $ 5.7 | $ 5.9 |
| CL&P | ||
| Summary of Accounting Policies [Line Items] | ||
| Period of accounts receivable recoverable under financial or medical duress | 180 days | |
| Yankee Gas | ||
| Summary of Accounting Policies [Line Items] | ||
| Period of accounts receivable recoverable under financial or medical duress | 90 days | |
| Connecticut, Massachusetts and New Hampshire | ||
| Summary of Accounting Policies [Line Items] | ||
| Number of regulated utilities | regulatedUtility | 12 |