GOODWILL - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Oct. 01, 2025
Goodwill [Line Items]
Income Tax Expense			$ 140,286	$ 424,664	$ 159,684
Goodwill	$ 4,233,767	$ 3,571,333	4,233,767	3,571,333	4,532,100
Disposal Group, Held-for-Sale, Not Discontinued Operations | Aquarion
Goodwill [Line Items]
Income Tax Expense				140,000
Goodwill impairment		297,000
Water Acquisitions
Goodwill [Line Items]
Goodwill disposed of				1,200
Goodwill impairment				297,000
Water Distribution
Goodwill [Line Items]
Goodwill disposed of				5,400
Sale of Water Unregulated Business and Water Acquisition, net				4,200
Goodwill impairment	0
Goodwill	$ 662,400	0	$ 662,400	0	$ 960,700	$ 662,500
Water Distribution | Water Acquisitions
Goodwill [Line Items]
Goodwill disposed of				$ 1,200
Goodwill impairment		$ 297,000