RATE MATTERS - APCo and WPCo Rate Matters (Details) - APPALACHIAN POWER COMPANY - USD ($) $ in Millions	1 Months Ended
	Apr. 30, 2026	Feb. 28, 2026	Sep. 30, 2025	Mar. 31, 2024	Jan. 31, 2024	Mar. 31, 2026	Nov. 30, 2025	Aug. 31, 2025	Jul. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Feb. 29, 2024
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization						$ 2,607
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
Storm-Related Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization						158
West Virginia
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization						2,600
VIRGINIA
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization									$ 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 Portion
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization						1,614
APCo Portion | 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 Portion | Storm-Related Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization						$ 155
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
Approved carrying charges					4.00%
Approved carrying charges, recovery period					10 years
Reduction of under-recovered costs disallowance										$ 179
ENEC Filing | APCo Portion
Public Utilities, General Disclosures [Line Items]
Under recovered costs disallowance					$ 136
Approved recovery under recovered costs					$ 174
2024 West Virginia Base Rate Case
Public Utilities, General Disclosures [Line Items]
Approved return on equity		9.75%
Approved annual base rate increase		$ 91	$ 76
2024 West Virginia Base Rate Case | APCo Portion
Public Utilities, General Disclosures [Line Items]
Approved annual base rate increase		$ 79	$ 67
West Virginia Modified Rate Base Cost
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)				$ 32
West Virginia Modified Rate Base Cost | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Public utilities, surcharge duration	4 years