NSTAR ELECTRIC COMPANY AND SUBSIDIARY CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Operating Revenues	$ 13,547,244	$ 11,900,809	$ 11,910,705
Operating Expenses:
Purchased Power and Transmission	4,209,172	3,736,078	5,168,241
Operations and Maintenance	2,073,778	2,012,926	1,895,703
Depreciation	1,568,578	1,433,503	1,305,840
Energy Efficiency Programs	778,348	671,828	691,344
Taxes Other Than Income Taxes	1,092,870	997,901	940,359
Total Operating Expenses	10,558,655	9,492,100	9,511,370
Operating Income	2,988,589	2,408,709	2,399,335
Interest Expense	1,243,266	1,111,336	855,441
Other Income, Net	378,854	410,482	348,069
Income/(Loss) Before Income Tax Expense	1,840,177	1,243,836	(275,037)
Income Tax Expense	140,286	424,664	159,684
NSTAR Electric Company
Operating Revenues	3,986,599	3,720,877	3,515,539
Operating Expenses:
Purchased Power and Transmission	1,141,748	1,045,306	1,154,013
Operations and Maintenance	792,319	735,019	668,466
Depreciation	446,045	407,699	372,578
Amortization of Regulatory Assets/(Liabilities), Net	107,553	130,869	16,150
Energy Efficiency Programs	294,343	263,405	325,593
Taxes Other Than Income Taxes	320,523	280,261	256,090
Total Operating Expenses	3,102,531	2,862,559	2,792,890
Operating Income	884,068	858,318	722,649
Interest Expense	256,061	222,794	189,254
Other Income, Net	192,646	191,405	164,129
Income/(Loss) Before Income Tax Expense	820,653	826,929	697,524
Income Tax Expense	190,030	190,576	152,996
Net Income/(Loss)	$ 630,623	$ 636,353	$ 544,528