GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Goodwill [Line Items]
Goodwill	$ 706,960,000		$ 706,960,000
Amortization expense	1,500,000	$ 1,500,000
Impairment of identifiable intangible assets	0	$ 0
ETG Utility Operations
Goodwill [Line Items]
Goodwill	700,200,000		700,200,000
Retail Services
Goodwill [Line Items]
Goodwill	$ 6,800,000		$ 6,800,000