SCHEDULE I - FINANCIAL INFORMATION OF REGISTRANT - STATEMENTS OF COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed Statement of Income Captions [Line Items]
Net Income	$ 1,412,394	$ 1,228,046	$ 1,212,686
Other Comprehensive Income/(Loss), Net of Tax:
Qualified Cash Flow Hedging Instruments	20	972	1,596
Changes in Unrealized (Losses)/Gains on Marketable Securities	(1,636)	(671)	342
Changes in Funded Status of Pension, SERP and PBOP Benefit Plans	4,470	33,835	(13,290)
Other Comprehensive Income/(Loss), Net of Tax	2,854	34,136	(11,352)
Comprehensive Income	1,407,729	1,254,663	1,193,815
Eversource
Condensed Statement of Income Captions [Line Items]
Net Income	1,404,875	1,220,527	1,205,167
Other Comprehensive Income/(Loss), Net of Tax:
Qualified Cash Flow Hedging Instruments	20	972	1,596
Changes in Unrealized (Losses)/Gains on Marketable Securities	(1,636)	(671)	342
Changes in Funded Status of Pension, SERP and PBOP Benefit Plans	4,470	33,835	(13,290)
Other Comprehensive Income/(Loss), Net of Tax	2,854	34,136	(11,352)
Comprehensive Income	$ 1,407,729	$ 1,254,663	$ 1,193,815