DERIVATIVES AND HEDGING - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Dec. 31, 2025
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cash collateral received from third-parties	$ 56	$ 83
Fair value of derivative liabilities subject to cross acceleration provisions	33	30
Fair value of derivative liabilities subject to cross default provisions	159	183
APCo
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value of derivative liabilities subject to cross default provisions	7	2
PSO
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value of derivative liabilities subject to cross default provisions	35	27
SWEPCo
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value of derivative liabilities subject to cross default provisions	$ 13	$ 10
Commodity
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Maximum length of time to hedge exposure to variability	9 years
Cross acceleration provisions maximum third party obligation amount	$ 50
Cross default provisions maximum third party obligation amount	$ 50