RATE MATTERS - APCo and WPCo Rate Matters (Details) - APCo $ in Millions	1 Months Ended
	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 ($)	Jan. 31, 2025 USD ($)	Feb. 29, 2024 USD ($)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		$ 2,395.8
ENEC Under-Recovery Regulatory Assets (as of February 28, 2023)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		321.1
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		1,704.2
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		236.8
Storm-Related Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		117.9
Upfront Financing Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		15.8
West Virginia
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		2,400.0
West Virginia | ENEC Under-Recovery Regulatory Assets (as of February 28, 2023)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		321.0
West Virginia | 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		237.0
West Virginia | Storm-Related Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		118.0
APCo Portion
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		1,532.5
APCo Portion | ENEC Under-Recovery Regulatory Assets (as of February 28, 2023)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		174.3
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		1,145.5
APCo Portion | 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		87.6
APCo Portion | Storm-Related Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		115.0
APCo Portion | Upfront Financing Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		10.1
Mitchell & Mountaineer Plants | West 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		1,700.0
WPCo Portion
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		863.3
WPCo Portion | ENEC Under-Recovery Regulatory Assets (as of February 28, 2023)
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		146.8
WPCo 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		558.7
WPCo Portion | 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		149.2
WPCo Portion | Storm-Related Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		2.9
WPCo Portion | Upfront Financing Costs
Public Utilities, General Disclosures [Line Items]
Regulatory asset, requested to be financed through securitization		5.7
ENEC Filing
Public Utilities, General Disclosures [Line Items]
Under recovered costs disallowance		232.0					$ 232.0		$ 232.0
Approved recovery under recovered costs					$ 321.0
Approved carrying charges					4.00%		4.00%
Approved carrying charges, recovery period					10 years		10 years
Requested annual base rate increase					$ 58.0
ENEC Filing | Period ending February 29, 2024
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase					20.0
Approved annual base rate increase		$ 20.0
ENEC Filing | Period September 2024 through August 2025
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase					$ 38.0
Approved annual base rate increase				$ 38.0
ENEC Filing | APCo Portion
Public Utilities, General Disclosures [Line Items]
Under recovered costs disallowance							$ 136.0
Approved recovery under recovered costs							$ 174.0
Virginia Fuel Adjustment Clause
Public Utilities, General Disclosures [Line Items]
Under recovered costs disallowance								$ 20.0
Virginia Fuel Adjustment Clause | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Under recovered costs disallowance	$ 20.0
2024 West Virginia Base Rate Case
Public Utilities, General Disclosures [Line Items]
Approved recovery under recovered costs			$ 118.0
Requested annual base rate increase			$ 251.0
Requested return on equity			10.80%
Requested debt capital structure			52.00%
Requested equity capital structure			48.00%
Regulatory assets expected to be recovered through securitization			$ 2,400.0
Requested annual increase without securitization			$ 37.0
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
Requested recovery, under-recovered costs, period			3 years
2024 West Virginia Base Rate Case | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Average rate base	13 months
Requested recovery, under-recovered costs	$ 118.0
Requested recovery, under-recovered costs, period	5 years
2024 West Virginia Base Rate Case | Subsequent Event | Minimum
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase	$ 49.0
Requested return on equity	9.10%
2024 West Virginia Base Rate Case | Subsequent Event | Maximum
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase	$ 91.0
Requested return on equity	9.25%
Modified Rate Base Cost
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase			$ 94.0
Mitchell Base Rate Surcharge
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase			$ 21.0
West Virginia Modified Rate Base Cost
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase						$ 32.0