THE CONNECTICUT LIGHT AND POWER COMPANY 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 Income (Loss)	The Connecticut Light and Power Company	The Connecticut Light and Power Company Adoption of New Accounting Standard	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 Retained Earnings Adoption of New Accounting Standard	The Connecticut Light and Power Company Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2019			329,880,645							6,035,205
Beginning balance at Dec. 31, 2019	$ 12,629,994	$ (1,514)	$ 1,729,292	$ 7,087,768	$ 4,177,048	$ (1,514)	$ (65,059)	$ 4,387,825	$ (900)	$ 60,352	$ 2,535,765	$ 1,791,392	$ (900)	$ 316
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,212,686				1,212,686			457,934				457,934
Dividends on Preferred Stock	(7,519)				(7,519)			(5,559)				(5,559)
Dividends on Common Stock	(767,500)				(767,500)			(69,500)				(69,500)
Capital Contributions from Eversource Parent								275,000			275,000
Other Comprehensive Income/(Loss), Net of Tax	(11,352)						(11,352)	(14)						(14)
Ending balance (in shares) at Dec. 31, 2020			342,954,023							6,035,205
Ending 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	1,228,046				1,228,046			401,725				401,725
Dividends on Preferred Stock	(7,519)				(7,519)			(5,559)				(5,559)
Dividends on Common Stock	(828,337)				(828,337)			(341,400)				(341,400)
Capital Contributions from Eversource Parent	160,000							200,000			200,000
Other Comprehensive Income/(Loss), Net of Tax	$ 34,136						34,136	(51)						(51)
Ending balance (in shares) at Dec. 31, 2021	344,403,196		344,403,196							6,035,205
Ending 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	1,412,394				1,412,394			532,920				532,920
Dividends on Preferred Stock	(7,519)				(7,519)			(5,559)				(5,559)
Dividends on Common Stock	(883,113)				(883,113)			(292,400)				(292,400)
Capital Contributions from Eversource Parent								250,000			250,000
Other Comprehensive Income/(Loss), Net of Tax	$ 2,854						2,854	(82)						(82)
Ending balance (in shares) at Dec. 31, 2022	348,443,855		348,443,855							6,035,205
Ending balance at Dec. 31, 2022	$ 15,473,158		$ 1,799,920	$ 8,401,731	$ 5,527,153		$ (39,421)	$ 5,784,380		$ 60,352	$ 3,260,765	$ 2,463,094		$ 169