SEGMENT INFORMATION - Summary of Segment Information and Segmented Total Assets (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Operating Revenues	$ 2,533,522		$ 2,629,342	$ 5,866,097	$ 6,424,985
Depreciation and Amortization	(240,400)		(101,500)	(578,000)	(338,500)
Other Operating Expenses	(1,690,600)		(1,967,100)	(3,839,600)	(4,776,300)
Operating Income	602,498		560,662	1,448,470	1,310,234
Interest Expense	(271,300)		(207,300)	(522,100)	(401,900)
Impairment of Offshore Wind Investment	0	$ (1,770,000)	(401,000)	0	(401,000)
Other Income, Net	115,285		94,875	206,315	183,857
Net Income Attributable to Common Shareholders	335,341		15,422	857,190	506,581
Cash Flows Used for Investments in Plant				2,220,900	2,039,500
Assets	58,352,454	55,612,245		58,352,454
Other
Segment Reporting Information [Line Items]
Operating Revenues	395,200		408,800	838,800	822,700
Depreciation and Amortization	(48,500)		(38,000)	(94,100)	(74,800)
Other Operating Expenses	(314,200)		(337,200)	(663,700)	(676,900)
Operating Income	32,500		33,600	81,000	71,000
Interest Expense	(161,000)		(100,600)	(307,200)	(185,700)
Impairment of Offshore Wind Investment			(401,000)		(401,000)
Other Income, Net	473,500		100,900	1,096,200	666,800
Net Income Attributable to Common Shareholders	351,800		(292,400)	892,300	224,700
Cash Flows Used for Investments in Plant				125,600	139,100
Assets	28,662,100	26,337,700		28,662,100
Eliminations
Segment Reporting Information [Line Items]
Operating Revenues	(813,100)		(781,200)	(1,649,800)	(1,542,100)
Depreciation and Amortization	2,700		2,200	5,200	4,300
Other Operating Expenses	810,400		779,500	1,644,600	1,538,800
Operating Income	0		500	0	1,000
Interest Expense	58,600		34,400	113,300	66,400
Impairment of Offshore Wind Investment			0		0
Other Income, Net	(448,900)		(74,600)	(1,063,000)	(625,300)
Net Income Attributable to Common Shareholders	(390,300)		(39,700)	(949,700)	(557,900)
Cash Flows Used for Investments in Plant				0	0
Assets	(28,726,000)	(26,678,500)		(28,726,000)
Electric Distribution | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenues	1,966,300		2,054,400	4,228,000	4,643,000
Depreciation and Amortization	(34,900)		82,100	(144,600)	60,000
Other Operating Expenses	(1,713,600)		(1,905,200)	(3,618,700)	(4,247,400)
Operating Income	217,800		231,300	464,700	455,600
Interest Expense	(90,900)		(68,200)	(173,400)	(137,600)
Impairment of Offshore Wind Investment			0		0
Other Income, Net	67,000		47,900	123,500	102,100
Net Income Attributable to Common Shareholders	149,700		165,500	317,900	331,000
Cash Flows Used for Investments in Plant				883,600	817,300
Assets	30,943,900	29,426,400		30,943,900
Natural Gas Distribution | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenues	393,500		409,100	1,299,500	1,454,300
Depreciation and Amortization	(50,100)		(41,700)	(133,200)	(118,700)
Other Operating Expenses	(295,200)		(339,400)	(849,800)	(1,069,800)
Operating Income	48,200		28,000	316,500	265,800
Interest Expense	(22,300)		(21,500)	(46,800)	(42,700)
Impairment of Offshore Wind Investment			0		0
Other Income, Net	10,900		9,700	21,000	18,700
Net Income Attributable to Common Shareholders	27,100		11,700	217,600	181,900
Cash Flows Used for Investments in Plant				467,900	371,500
Assets	9,036,600	8,775,300		9,036,600
Electric Transmission | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenues	534,100		480,100	1,041,900	938,800
Depreciation and Amortization	(98,800)		(92,000)	(199,800)	(181,900)
Other Operating Expenses	(147,100)		(136,200)	(289,000)	(264,500)
Operating Income	288,200		251,900	553,100	492,400
Interest Expense	(46,000)		(42,200)	(86,900)	(83,700)
Impairment of Offshore Wind Investment			0		0
Other Income, Net	12,200		9,500	26,300	18,900
Net Income Attributable to Common Shareholders	189,000		161,000	365,700	316,100
Cash Flows Used for Investments in Plant				668,100	636,900
Assets	15,417,300	14,806,500		15,417,300
Water Distribution | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenues	57,500		58,100	107,700	108,300
Depreciation and Amortization	(10,800)		(14,100)	(11,500)	(27,400)
Other Operating Expenses	(30,900)		(28,600)	(63,000)	(56,500)
Operating Income	15,800		15,400	33,200	24,400
Interest Expense	(9,700)		(9,200)	(21,100)	(18,600)
Impairment of Offshore Wind Investment			0		0
Other Income, Net	600		1,500	2,300	2,700
Net Income Attributable to Common Shareholders	8,000		$ 9,300	13,400	10,800
Cash Flows Used for Investments in Plant				75,700	$ 74,700
Assets	$ 3,018,600	$ 2,944,800		$ 3,018,600