NSTAR ELECTRIC COMPANY AND SUBSIDIARY CONSOLIDATED STATEMENTS OF COMMON STOCKHOLDER'S EQUITY - USD ($) $ in Thousands	Total	Common Stock	Capital Surplus, Paid In	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	NSTAR Electric	NSTAR Electric Common Stock	NSTAR Electric Capital Surplus, Paid In	NSTAR Electric Retained Earnings	NSTAR Electric Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2022		348,443,855					200
Beginning balance at Dec. 31, 2022	$ 15,473,158	$ 1,799,920	$ 8,401,731	$ 5,527,153	$ (39,421)	$ 5,700,670	$ 0	$ 2,778,942	$ 2,921,444	$ 284
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income/(Loss)						544,528			544,528
Dividends on Preferred Stock	(7,519)			(7,519)		(1,960)			(1,960)
Dividends on Common Stock	(942,398)			(942,398)		(327,400)			(327,400)
Capital Contributions from Eversource Parent						234,900		234,900
Other Comprehensive Income/(Loss), Net of Tax						(240)				(240)
Ending balance (in shares) at Dec. 31, 2023		349,540,266					200
Ending balance at Dec. 31, 2023	14,173,892	$ 1,799,920	8,460,876	4,142,515	(33,737)	6,150,498	$ 0	3,013,842	3,136,612	44
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income/(Loss)						636,353			636,353
Dividends on Preferred Stock	(7,519)			(7,519)		(1,960)			(1,960)
Dividends on Common Stock	$ (1,025,027)			(1,025,027)		(643,900)			(643,900)
Capital Contributions from Eversource Parent						775,000		775,000
Other Comprehensive Income/(Loss), Net of Tax					7,200	(185)				(185)
Ending balance (in shares) at Dec. 31, 2024	366,608,052	366,608,052					200
Ending balance at Dec. 31, 2024	$ 15,039,387	$ 1,878,622	9,428,905	3,929,141	(26,472)	6,915,806	$ 0	3,788,842	3,127,105	(141)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income/(Loss)						630,623			630,623
Dividends on Preferred Stock	(7,519)			(7,519)		(1,960)			(1,960)
Dividends on Common Stock	$ (1,116,530)			(1,116,530)		(436,000)			(436,000)
Capital Contributions from Eversource Parent						450,000		450,000
Other Comprehensive Income/(Loss), Net of Tax					6,000	366				366
Ending balance (in shares) at Dec. 31, 2025	375,416,880	375,416,880					200
Ending balance at Dec. 31, 2025	$ 16,197,271	$ 1,914,273	$ 9,937,878	$ 4,504,983	$ (20,507)	$ 7,558,835	$ 0	$ 4,238,842	$ 3,319,768	$ 225