PUBLIC SERVICE COMPANY OF NEW HAMPSHIRE AND SUBSIDIARIES CONSOLIDATED STATEMENTS OF COMMON STOCKHOLDER'S EQUITY - USD ($) $ in Thousands	Total	Adoption of New Accounting Standard	Common Stock	Capital Surplus, Paid In	Retained Earnings	Retained Earnings Adoption of New Accounting Standard	Accumulated Other Comprehensive Loss	Public Service Company of New Hampshire	Public Service Company of New Hampshire Adoption of New Accounting Standard	Public Service Company of New Hampshire Common Stock	Public Service Company of New Hampshire Capital Surplus, Paid In	Public Service Company of New Hampshire Retained Earnings	Public Service Company of New Hampshire Retained Earnings Adoption of New Accounting Standard	Public Service Company of New Hampshire Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2018			316,885,808							301
Beginning balance at Dec. 31, 2018	$ 11,486,817		$ 1,669,392	$ 6,241,222	$ 3,953,974		$ (60,000)	$ 1,302,541		$ 0	$ 678,134	$ 627,258		$ (2,851)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2016-13 [Member]							Accounting Standards Update 2016-13 [Member]
Net Income	$ 916,572				916,572			$ 134,048				134,048
Dividends on Common Stock								(271,000)				(271,000)
Capital Contributions from Eversource Parent								225,000			225,000
Dividends on Common Stock	(685,979)				(685,979)
Other Comprehensive Income/(Loss), Net of Tax	(5,059)						(5,059)	1,144						1,144
Ending balance (in shares) at Dec. 31, 2019			329,880,645							301
Ending balance at Dec. 31, 2019	12,629,994	$ (1,514)	$ 1,729,292	7,087,768	4,177,048	$ (1,514)	(65,059)	1,391,733	$ (300)	$ 0	903,134	490,306	$ (300)	(1,707)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,212,686				1,212,686			147,312				147,312
Capital Contributions from Eversource Parent	25,000										25,000
Dividends on Common Stock	(767,500)				(767,500)			(22,300)				(22,300)
Other Comprehensive Income/(Loss), Net of Tax	$ (11,352)						(11,352)	1,094						1,094
Ending balance (in shares) at Dec. 31, 2020	342,954,023		342,954,023							301
Ending balance at Dec. 31, 2020	$ 14,063,566		$ 1,789,092	8,015,663	4,613,201		(76,411)	1,542,539		$ 0	928,134	615,018		(613)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,228,046				1,228,046			150,338				150,338
Dividends on Common Stock								(260,800)				(260,800)
Capital Contributions from Eversource Parent								160,000			160,000
Dividends on Common Stock	(828,337)				(828,337)
Other Comprehensive Income/(Loss), Net of Tax	$ 34,136						34,136	636						636
Ending balance (in shares) at Dec. 31, 2021	344,403,196		344,403,196							301
Ending balance at Dec. 31, 2021	$ 14,599,844		$ 1,789,092	$ 8,098,514	$ 5,005,391		$ (42,275)	$ 1,592,713		$ 0	$ 1,088,134	$ 504,556		$ 23