REGULATORY MATTERS (Cost Recovery Mechanisms) (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		12 Months Ended
	Jan. 31, 2024	May 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2025	Dec. 31, 2023	Dec. 31, 2021	Mar. 31, 2022
Effective 1/1/2024-12/31/2026
Regulatory Assets [Roll Forward]
Energy efficiency implementation plan term						3 years
Purchased Power and Fuel Adjustment Clause
Public Utilities, General Disclosures [Line Items]
Months approved rate in effect unless modified			12 months
Period of recovery of uncollected true-up balance, approved		12 months
Regulatory Assets [Roll Forward]
Beginning of Period	$ 55		$ 55	$ 124		$ 124
Deferred Fuel and Purchased Power Costs			49	58
PPFAC and Base Power Recoveries			(97)	(64)
End of Period			$ 7	$ 118		55
Renewable Energy Standard
Regulatory Assets [Roll Forward]
Renewable Energy Required Percentage			14.00%
Approved spending budget for the years of 2021 and 2022							$ 66
Proposed renewable energy standard increase in tariff amount						17
Renewable Energy Standard | Scenario, Forecast
Regulatory Assets [Roll Forward]
Renewable energy target percentage					15.00%
Distributed generation requirement percent of target percentage (percentage)					30.00%
Energy Efficiency Standards
Regulatory Assets [Roll Forward]
Annual energy efficiency target, percentage								1.30%
Energy Efficiency Standards | Effective 1/1/2024-12/31/2026
Regulatory Assets [Roll Forward]
Approved recovery of spending budget						$ 72
Approval to refund an over-collected balance	$ 10
Period of refund for over-collected balance	1 year
Lost Fixed Cost Recovery
Regulatory Assets [Roll Forward]
Cap on increase in lost fixed cost recovery rate (percentage)			2.00%