THE CONNECTICUT LIGHT AND POWER COMPANY CONDENSED STATEMENTS OF COMMON STOCKHOLDER'S EQUITY - USD ($) $ in Thousands	Total	Common Stock	Capital Surplus, Paid In	Retained Earnings	Accumulated Other Comprehensive Loss	The Connecticut Light and Power Company	The Connecticut Light and Power Company Common Stock	The Connecticut Light and Power Company Capital Surplus, Paid In	The Connecticut Light and Power Company Retained Earnings	The Connecticut Light and Power Company Accumulated Other Comprehensive Loss
Balance (in shares) at Dec. 31, 2020		342,954,023					6,035,205
Balance at Dec. 31, 2020	$ 14,063,566	$ 1,789,092	$ 8,015,663	$ 4,613,201	$ (76,411)	$ 5,044,786	$ 60,352	$ 2,810,765	$ 2,173,367	$ 302
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	368,023			368,023		98,398			98,398
Dividends on Preferred Stock	(1,880)			(1,880)		(1,390)			(1,390)
Dividends on Common Stock	(206,913)			(206,913)		(70,100)			(70,100)
Other Comprehensive Income, Net of Tax	1,188				1,188	(32)				(32)
Balance (in shares) at Mar. 31, 2021		343,434,298					6,035,205
Balance at Mar. 31, 2021	14,233,420	$ 1,789,092	8,016,118	4,772,431	(75,223)	5,071,662	$ 60,352	2,810,765	2,200,275	270
Balance (in shares) at Dec. 31, 2020		342,954,023					6,035,205
Balance at Dec. 31, 2020	14,063,566	$ 1,789,092	8,015,663	4,613,201	(76,411)	5,044,786	$ 60,352	2,810,765	2,173,367	302
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	919,468					284,107
Dividends on Preferred Stock	(5,600)
Other Comprehensive Income, Net of Tax	4,546					(38)
Balance (in shares) at Sep. 30, 2021		343,774,324					6,035,205
Balance at Sep. 30, 2021	14,411,611	$ 1,789,092	8,050,872	4,906,151	(71,865)	5,114,385	$ 60,352	2,810,765	2,243,004	264
Balance (in shares) at Mar. 31, 2021		343,434,298					6,035,205
Balance at Mar. 31, 2021	14,233,420	$ 1,789,092	8,016,118	4,772,431	(75,223)	5,071,662	$ 60,352	2,810,765	2,200,275	270
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	266,400			266,400		115,556			115,556
Dividends on Preferred Stock	(1,880)			(1,880)		(1,390)			(1,390)
Dividends on Common Stock	(206,893)			(206,893)		(70,100)			(70,100)
Other Comprehensive Income, Net of Tax	881				881	3				3
Balance (in shares) at Jun. 30, 2021		343,601,103					6,035,205
Balance at Jun. 30, 2021	14,311,889	$ 1,789,092	8,032,959	4,830,058	(74,342)	5,115,731	$ 60,352	2,810,765	2,244,341	273
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	285,046			285,046		70,153			70,153
Dividends on Preferred Stock	(1,880)			(1,880)		(1,390)			(1,390)
Dividends on Common Stock	(207,073)			(207,073)		(70,100)			(70,100)
Other Comprehensive Income, Net of Tax	2,477				2,477	(9)				(9)
Balance (in shares) at Sep. 30, 2021		343,774,324					6,035,205
Balance at Sep. 30, 2021	$ 14,411,611	$ 1,789,092	8,050,872	4,906,151	(71,865)	5,114,385	$ 60,352	2,810,765	2,243,004	264
Balance (in shares) at Dec. 31, 2021	344,403,196	344,403,196					6,035,205
Balance at Dec. 31, 2021	$ 14,599,844	$ 1,789,092	8,098,514	5,005,391	(42,275)	5,299,501	$ 60,352	3,010,765	2,228,133	251
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	445,326			445,326		152,977			152,977
Dividends on Preferred Stock	(1,880)			(1,880)		(1,390)			(1,390)
Dividends on Common Stock	(219,768)			(219,768)		(73,100)			(73,100)
Capital Contributions from Eversource Parent						100,000		100,000
Other Comprehensive Income, Net of Tax	704				704	(35)				(35)
Balance (in shares) at Mar. 31, 2022		344,850,272					6,035,205
Balance at Mar. 31, 2022	$ 14,836,690	$ 1,789,092	8,102,618	5,229,069	(41,571)	5,477,953	$ 60,352	3,110,765	2,306,620	216
Balance (in shares) at Dec. 31, 2021	344,403,196	344,403,196					6,035,205
Balance at Dec. 31, 2021	$ 14,599,844	$ 1,789,092	8,098,514	5,005,391	(42,275)	5,299,501	$ 60,352	3,010,765	2,228,133	251
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,090,356					422,102
Dividends on Preferred Stock	(5,600)
Other Comprehensive Income, Net of Tax	$ 1,269					(88)
Balance (in shares) at Sep. 30, 2022	347,348,749	347,348,749					6,035,205
Balance at Sep. 30, 2022	$ 15,279,173	$ 1,799,920	8,327,477	5,429,076	(41,006)	5,698,045	$ 60,352	3,210,765	2,426,765	163
Balance (in shares) at Mar. 31, 2022		344,850,272					6,035,205
Balance at Mar. 31, 2022	14,836,690	$ 1,789,092	8,102,618	5,229,069	(41,571)	5,477,953	$ 60,352	3,110,765	2,306,620	216
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	293,742			293,742		125,838			125,838
Dividends on Preferred Stock	(1,880)			(1,880)		(1,390)			(1,390)
Dividends on Common Stock	(219,877)			(219,877)		(73,100)			(73,100)
Capital Contributions from Eversource Parent						100,000		100,000
Other Comprehensive Income, Net of Tax	(1,293)				(1,293)	(23)				(23)
Balance (in shares) at Jun. 30, 2022		346,411,029					6,035,205
Balance at Jun. 30, 2022	15,057,215	$ 1,796,056	8,242,346	5,301,054	(42,864)	5,629,278	$ 60,352	3,210,765	2,357,968	193
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	351,289			351,289		143,287			143,287
Dividends on Preferred Stock	(1,880)			(1,880)		(1,390)			(1,390)
Dividends on Common Stock	(221,387)			(221,387)		(73,100)			(73,100)
Other Comprehensive Income, Net of Tax	$ 1,858				1,858	(30)				(30)
Balance (in shares) at Sep. 30, 2022	347,348,749	347,348,749					6,035,205
Balance at Sep. 30, 2022	$ 15,279,173	$ 1,799,920	$ 8,327,477	$ 5,429,076	$ (41,006)	$ 5,698,045	$ 60,352	$ 3,210,765	$ 2,426,765	$ 163