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 Income/(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 Income/(Loss)
Beginning balance (in shares) at Dec. 31, 2022		348,443,855					6,035,205
Balance as of Beginning of Period 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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss)/Income						148,416			148,416
Dividends on Preferred Stock	(1,880)			(1,880)		(1,390)			(1,390)
Dividends on Common Stock	(235,354)			(235,354)		(82,600)			(82,600)
Other Comprehensive Income (Loss)						36				36
Ending balance (in shares) at Mar. 31, 2023		348,808,082					6,035,205
Balance as of End of Period at Mar. 31, 2023	15,749,371	$ 1,799,920	8,412,085	5,782,958	(36,191)	5,848,842	$ 60,352	3,260,765	2,527,520	205
Beginning balance (in shares) at Dec. 31, 2022		348,443,855					6,035,205
Balance as of Beginning of Period 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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss)/Income						401,104
Other Comprehensive Income (Loss)	15,400					22
Ending balance (in shares) at Sep. 30, 2023		349,275,775					6,035,205
Balance as of End of Period at Sep. 30, 2023	15,685,941	$ 1,799,920	8,443,820	5,666,861	(24,022)	6,057,036	$ 60,352	3,384,265	2,612,228	191
Beginning balance (in shares) at Mar. 31, 2023		348,808,082					6,035,205
Balance as of Beginning of Period at Mar. 31, 2023	15,749,371	$ 1,799,920	8,412,085	5,782,958	(36,191)	5,848,842	$ 60,352	3,260,765	2,527,520	205
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss)/Income						133,300			133,300
Dividends on Preferred Stock	(1,880)			(1,880)		(1,390)			(1,390)
Dividends on Common Stock	(235,491)			(235,491)		(82,600)			(82,600)
Other Comprehensive Income (Loss)						(7)				(7)
Ending balance (in shares) at Jun. 30, 2023		349,021,936					6,035,205
Balance as of End of Period at Jun. 30, 2023	15,554,098	$ 1,799,920	8,428,786	5,562,889	(32,103)	5,898,145	$ 60,352	3,260,765	2,576,830	198
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss)/Income						119,388			119,388
Dividends on Preferred Stock	(1,880)			(1,880)		(1,390)			(1,390)
Dividends on Common Stock	(235,691)			(235,691)		(82,600)			(82,600)
Capital Contributions from Eversource Parent						123,500		123,500
Other Comprehensive Income (Loss)						(7)				(7)
Ending balance (in shares) at Sep. 30, 2023		349,275,775					6,035,205
Balance as of End of Period at Sep. 30, 2023	$ 15,685,941	$ 1,799,920	8,443,820	5,666,861	(24,022)	6,057,036	$ 60,352	3,384,265	2,612,228	191
Beginning balance (in shares) at Dec. 31, 2023	349,540,266	349,540,266					6,035,205
Balance as of Beginning of Period at Dec. 31, 2023	$ 14,173,892	$ 1,799,920	8,460,876	4,142,515	(33,737)	6,090,670	$ 60,352	3,384,265	2,645,868	185
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss)/Income						138,353			138,353
Dividends on Preferred Stock	(1,880)			(1,880)		(1,390)			(1,390)
Dividends on Common Stock	(250,770)			(250,770)		(82,500)			(82,500)
Capital Contributions from Eversource Parent						100,000		100,000
Other Comprehensive Income (Loss)						(7)				(7)
Ending balance (in shares) at Mar. 31, 2024		351,379,414					6,035,205
Balance as of End of Period at Mar. 31, 2024	$ 14,543,588	$ 1,806,385	8,537,591	4,413,593	(28,534)	6,245,126	$ 60,352	3,484,265	2,700,331	178
Beginning balance (in shares) at Dec. 31, 2023	349,540,266	349,540,266					6,035,205
Balance as of Beginning of Period at Dec. 31, 2023	$ 14,173,892	$ 1,799,920	8,460,876	4,142,515	(33,737)	6,090,670	$ 60,352	3,384,265	2,645,868	185
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss)/Income						401,844
Other Comprehensive Income (Loss)	$ 5,500					(20)
Ending balance (in shares) at Sep. 30, 2024	363,891,973	363,891,973					6,035,205
Balance as of End of Period at Sep. 30, 2024	$ 15,044,424	$ 1,866,385	9,263,434	4,118,654	(28,205)	6,540,724	$ 60,352	3,684,265	2,795,942	165
Beginning balance (in shares) at Mar. 31, 2024		351,379,414					6,035,205
Balance as of Beginning of Period at Mar. 31, 2024	14,543,588	$ 1,806,385	8,537,591	4,413,593	(28,534)	6,245,126	$ 60,352	3,484,265	2,700,331	178
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss)/Income						131,601			131,601
Dividends on Preferred Stock	(1,880)			(1,880)		(1,390)			(1,390)
Dividends on Common Stock	(252,104)			(252,104)
Capital Contributions from Eversource Parent						100,000		100,000
Other Comprehensive Income (Loss)						(6)				(6)
Ending balance (in shares) at Jun. 30, 2024		354,566,071					6,035,205
Balance as of End of Period at Jun. 30, 2024	14,818,713	$ 1,820,954	8,710,844	4,496,830	(29,581)	6,475,331	$ 60,352	3,584,265	2,830,542	172
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss)/Income						131,890			131,890
Dividends on Preferred Stock	(1,880)			(1,880)		(1,390)			(1,390)
Dividends on Common Stock	$ (260,119)			(260,119)		(165,100)			(165,100)
Capital Contributions from Eversource Parent						100,000		100,000
Other Comprehensive Income (Loss)						(7)				(7)
Ending balance (in shares) at Sep. 30, 2024	363,891,973	363,891,973					6,035,205
Balance as of End of Period at Sep. 30, 2024	$ 15,044,424	$ 1,866,385	$ 9,263,434	$ 4,118,654	$ (28,205)	$ 6,540,724	$ 60,352	$ 3,684,265	$ 2,795,942	$ 165