RATE MATTERS - SWEPCo Rate Matters (Details) - SWEPCo - USD ($) $ in Millions	1 Months Ended					12 Months Ended
	Oct. 29, 2025	Aug. 31, 2025	Mar. 31, 2025	Jan. 31, 2022	Oct. 31, 2020	Dec. 31, 2021
Public Utilities, General Disclosures [Line Items]
Requested return on equity		9.50%
Requested debt capital structure		54.80%
Requested equity capital structure		45.20%
Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested return on equity	9.50%
Requested debt capital structure	54.80%
Requested equity capital structure	45.20%
Pirkey Plant
Public Utilities, General Disclosures [Line Items]
Public utilities, recommended recovery amount		$ 37
Public utilities, remaining net book recovery period		20 years
Pirkey Plant | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Public utilities, recommended recovery amount	$ 37
Public utilities, remaining net book recovery period	20 years
Minimum
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)		$ 53
Minimum | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)	$ 53
Maximum
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)		$ 99
Maximum | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)	99
2020 Texas Base Rate Case
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)					$ 105
Requested return on equity					10.35%
Requested net annual increase					$ 90
Revised requested annual increase					100
Revised requested net annual increase					$ 85
Approved annual revenue increase				$ 39
Approved return on equity				9.25%
Amount of approved increase related to vegetation management				$ 5
Amount of approved increase related to storm catastrophe reserve				$ 2
Impairment charge total						$ 12
2025 Arkansas Base Rate Case
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)			$ 114
Requested return on equity			10.90%
Requested debt capital structure			52.30%
Requested equity capital structure			47.70%
2025 Texas Base Rate Case | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)	$ 164
Requested return on equity	10.75%
Requested net annual increase	$ 95
Requested debt capital structure	48.00%
Requested equity capital structure	52.00%
2025 Texas Base Rate Case | Pirkey Plant | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to recovery amount	$ 21