RATE MATTERS - APCo and WPCo Rate Matters (Details) - APPALACHIAN POWER COMPANY $ in Millions	1 Months Ended
	Sep. 30, 2025 USD ($)	Aug. 31, 2025 USD ($)	Apr. 30, 2025 USD ($)	Mar. 31, 2025 USD ($)	Nov. 30, 2024 USD ($) consecutiveYear	Aug. 31, 2024 USD ($)	Apr. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Jan. 31, 2024 USD ($)	Dec. 31, 2025 USD ($)	Nov. 30, 2025 USD ($)	Oct. 31, 2025 USD ($)	Jul. 31, 2025 USD ($)	Jun. 30, 2025 USD ($)	Jan. 31, 2025 USD ($)	Oct. 31, 2024 USD ($)	Feb. 29, 2024 USD ($)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization										$ 2,528
ENEC Under-Recovery Regulatory Assets
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization										413
Undepreciated Utility Plant Balances of Amos, Mitchell and Mountaineer (as of December 31, 2022)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization										1,704
Forecasted Undepreciated CCR and ELG Investments of Amos, Mitchell and Mountaineer (as of November 30, 2024)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization										237
Storm-Related Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization										158
WV
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization				$ 2,400
WV | ENEC Under-Recovery Regulatory Assets
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization				321
WV | Forecasted Undepreciated CCR and ELG Investments of Amos, Mitchell and Mountaineer (as of November 30, 2024)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization				237
WV | Storm-Related Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization				118
Virginia
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization												$ 1,400	$ 1,400
Regulatory asset, requested to be financed through securitization (in years)													20 years
Regulatory asset, requested to be financed through securitization, approved											$ 1,400
Virginia | Storm-Related Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization													$ 141
APCo
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization										1,565
APCo | ENEC Under-Recovery Regulatory Assets
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization										167
APCo | Undepreciated Utility Plant Balances of Amos, Mitchell and Mountaineer (as of December 31, 2022)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization										1,145
APCo | Forecasted Undepreciated CCR and ELG Investments of Amos, Mitchell and Mountaineer (as of November 30, 2024)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization										88
APCo | Storm-Related Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization										$ 155
Mitchell & Mountaineer Plants | WV | Undepreciated Utility Plant Balances of Amos, Mitchell and Mountaineer (as of December 31, 2022)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization				1,700
Mitchell Plant | KPCo
Public Utilities, General Disclosures [Line Items]
Share of energy and capacity utilized by other party, percentage										50.00%
Amos and Mountaineer Plants | Virginia
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization (in years)													20 years
Amos and Mountaineer Plants | Virginia | Undepreciated Utility Plant Balances of Amos, Mitchell and Mountaineer (as of December 31, 2022)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization													$ 1,200
ENEC Filing
Public Utilities, General Disclosures [Line Items]
Under recovered costs disallowance		$ 232		232					$ 232								$ 232
Approved recovery under recovered costs							$ 321		$ 321
Approved carrying charges							4.00%		4.00%
Approved carrying charges, recovery period							10 years		10 years
Reduction of under-recovered costs disallowance														$ 179
Requested annual base rate increase (decrease)			$ 72				$ 58
Approved annual base rate increase	$ 70
Public utilities, denied, under-recovered costs disallowance	$ 19
ENEC Filing | Period ending February 29, 2024
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)							20
Approved annual base rate increase				$ 20
ENEC Filing | Period September 2024 through August 2025
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)							$ 38
Approved annual base rate increase						$ 38
ENEC Filing | APCo
Public Utilities, General Disclosures [Line Items]
Under recovered costs disallowance									$ 136
Approved recovery under recovered costs									$ 174
Virginia Fuel Adjustment Clause
Public Utilities, General Disclosures [Line Items]
Under recovered costs disallowance										$ 0					$ 20	$ 0
Recommended increase (decrease) in rates														$ 0
Virginia 2021 & 2022 Fuel Cost Review Periods
Public Utilities, General Disclosures [Line Items]
Under recovered costs disallowance										$ 0
2024 West Virginia Base Rate Case
Public Utilities, General Disclosures [Line Items]
Approved recovery under recovered costs		24
Requested annual base rate increase (decrease)					$ 251
Approved annual base rate increase		$ 76
Requested return on equity					10.80%
Requested debt capital structure					52.00%
Requested equity capital structure					48.00%
Requested recovery, under-recovered costs, period					3 years
Annual increase april 1st surcharge		3.00%
Approved return on equity		9.25%
Approved debt capital structure		56.00%
Approved equity capital structure		44.00%
2024 West Virginia Base Rate Case | APCo
Public Utilities, General Disclosures [Line Items]
Approved annual base rate increase		$ 67
Modified Rate Base Cost
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)					$ 94
Mitchell Base Rate Surcharge
Public Utilities, General Disclosures [Line Items]
Approved recovery under recovered costs					118
Requested annual base rate increase (decrease)					21
Regulatory assets expected to be recovered through securitization					2,400
Requested annual increase without securitization					$ 37
Annual increase april 1st surcharge					3.00%
Annual increase, surcharges, number of consecutive years | consecutiveYear					4
Annual increase april 1st surcharge, proposed filing period					4 years
West Virginia Modified Rate Base Cost
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)								$ 32