SCHEDULE I - FINANCIAL INFORMATION OF REGISTRANT - BALANCE SHEET (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current Assets:
Cash	$ 47,597	$ 66,773
Prepayments and Other Current Assets	382,603	369,759
Total Current Assets	4,223,198	3,270,120
Deferred Debits and Other Assets:
Investments in Subsidiary Companies, at Equity	2,176,080	1,436,293
Goodwill	4,522,632	4,477,269	$ 4,446,000
Other Long-Term Assets	541,344	611,769
Total Deferred Debits and Other Assets	12,894,882	11,844,374
Total Assets (as of)	53,230,900	48,492,144
Current Liabilities:
Notes Payable	1,442,200	1,505,450
Long-Term Debt – Current Portion	1,320,129	1,193,097
Other Current Liabilities	989,053	830,620
Total Current Liabilities	6,799,283	5,847,039
Liabilities, Noncurrent [Abstract]
Other Long-Term Liabilities	888,081	971,080
Total Deferred Credits and Other Liabilities	10,668,403	10,412,412
Capitalization:
Long-Term Debt	19,723,994	17,023,577
Common Shareholders' Equity:
Capital Surplus, Paid in	8,401,731	8,098,514
Retained Earnings	5,527,153	5,005,391
Accumulated Other Comprehensive Loss	(39,421)	(42,275)
Treasury Stock	(216,225)	(250,878)
Stockholders' equity	15,473,158	14,599,844	$ 14,063,566	$ 12,629,994
Total Liabilities and Capitalization	53,230,900	48,492,144
Eversource
Current Assets:
Cash	971	175
Accounts Receivable from Subsidiaries	53,338	43,403
Notes Receivable from Subsidiaries	1,074,800	1,245,900
Prepayments and Other Current Assets	23,597	11,974
Total Current Assets	1,152,706	1,301,452
Deferred Debits and Other Assets:
Investments in Subsidiary Companies, at Equity	18,379,840	16,108,190
Notes Receivable from Subsidiaries	1,896,500	1,001,000
Accumulated Deferred Income Taxes	0	17,409
Goodwill	3,852,524	3,852,524
Other Long-Term Assets	108,867	101,710
Total Deferred Debits and Other Assets	24,237,731	21,080,833
Total Assets (as of)	25,390,437	22,382,285
Current Liabilities:
Notes Payable	1,442,200	1,342,950
Long-Term Debt – Current Portion	1,207,047	767,681
Accounts Payable to Subsidiaries	33,530	37,609
Other Current Liabilities	112,807	87,745
Total Current Liabilities	2,795,584	2,235,985
Liabilities, Noncurrent [Abstract]
Accumulated Deferred Income Taxes	8,498	0
Other Long-Term Liabilities	140,393	150,616
Total Deferred Credits and Other Liabilities	148,891	150,616
Capitalization:
Long-Term Debt	6,972,804	5,395,840
Common Shareholders' Equity:
Common Shares	1,799,920	1,789,092
Capital Surplus, Paid in	8,401,731	8,098,514
Retained Earnings	5,527,153	5,005,391
Accumulated Other Comprehensive Loss	(39,421)	(42,275)
Treasury Stock	(216,225)	(250,878)
Stockholders' equity	15,473,158	14,599,844
Total Liabilities and Capitalization	$ 25,390,437	$ 22,382,285