DERIVATIVES - Schedule of Gain (Loss) On Natural Gas Purchase Derivatives (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Non-cash loss (gain) from natural gas purchase derivatives	$ 12	$ (18)
Settlements	12	12
Net loss (gain) from natural gas purchase derivatives	$ 24	$ (6)

The difference between the book value and the sale price of options, swaps, futures, forward contracts, and other derivative instruments. This element refers to the gain (loss) included in earnings.

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Period Type:	duration