CONSOLIDATED STATEMENTS OF INCOME/(LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Income Statement [Abstract]
Operating Revenues	$ 13,547,244	$ 11,900,809	$ 11,910,705
Operating Expenses:
Purchased Power, Purchased Natural Gas 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
Amortization	835,909	342,864	(490,117)
Energy Efficiency Programs	778,348	671,828	691,344
Taxes Other Than Income Taxes	1,092,870	997,901	940,359
Loss on Pending Sale of Aquarion	0	297,000	0
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
Losses on Offshore Wind	284,000	464,019	2,167,000
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
Net Income/(Loss)	1,699,891	819,172	(434,721)
Net Income Attributable to Noncontrolling Interests	7,519	7,519	7,519
Net Income/(Loss) Attributable to Common Shareholders	$ 1,692,372	$ 811,653	$ (442,240)
Basic Earnings/(Loss) Per Common Share (in dollars per share)	$ 4.56	$ 2.27	$ (1.27)
Diluted Earnings/(Loss) Per Common Share (in dollars per share)	$ 4.56	$ 2.27	$ (1.26)
Weighted Average Common Shares Outstanding:
Basic (in shares)	370,852,601	357,482,965	349,580,638
Diluted (in shares)	371,259,264	357,779,408	349,840,481