SIGNIFICANT ACCOUNTING POLICIES AND OTHER FINANCIAL DATA - OTHER INTANGIBLE ASSETS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 1,602	$ 1,602	$ 1,602
Total intangible assets, gross	440	250	250
Accumulated amortization	(70)	(48)	(37)
Other intangible assets	370	202	213
Intangible assets amortization expense	22	11	11
Amortization recorded against revenues	10
Expected amortization, year one	26
Expected amortization, year two	26
Expected amortization, year three	26
Expected amortization, year four	26
Expected amortization, year five	26
Expected amortization expense recorded against revenue, next five years	13
Renewable energy transmission and consumption permits
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	169	169	169
Accumulated amortization	$ (40)	(32)	(24)
Renewable energy transmission and consumption permits | Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization period	15 years
Renewable energy transmission and consumption permits | Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization period	19 years
O&M agreement
Finite-Lived Intangible Assets [Line Items]
Amortization period	23 years
Intangible assets, gross	$ 66	66	66
Accumulated amortization	$ (12)	(9)	(6)
ESJ PPA
Finite-Lived Intangible Assets [Line Items]
Amortization period	14 years
Intangible assets, gross	$ 190	0	0
Accumulated amortization	(10)	0	0
Other
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	15	15	15
Accumulated amortization	$ (8)	$ (7)	$ (7)
Other | Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization period	10 years