RATE MATTERS - Regulatory Assets Subject to Securitization (Details) - APPALACHIAN POWER COMPANY - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Regulatory Asset [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)
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	1,704
ENEC Under-Recovery Regulatory Assets
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	492
Forecasted Undepreciated CCR and ELG Investments of Amos, Mitchell and Mountaineer (as of November 30, 2024)
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	237
Deferred Storm Other Operation and Maintenance Expense Regulatory Assets
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	158
Upfront Financing Costs
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	16
APCo Portion
Regulatory Asset [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)
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	1,145
APCo Portion | ENEC Under-Recovery Regulatory Assets
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	216
APCo Portion | Forecasted Undepreciated CCR and ELG Investments of Amos, Mitchell and Mountaineer (as of November 30, 2024)
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	88
APCo Portion | Deferred Storm Other Operation and Maintenance Expense Regulatory Assets
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	155
APCo Portion | Upfront Financing Costs
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	10
WPCo Portion
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	993
WPCo Portion | Undepreciated Utility Plant Balances of Amos, Mitchell and Mountaineer (as of December 31, 2022)
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	559
WPCo Portion | ENEC Under-Recovery Regulatory Assets
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	276
WPCo Portion | Forecasted Undepreciated CCR and ELG Investments of Amos, Mitchell and Mountaineer (as of November 30, 2024)
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	149
WPCo Portion | Deferred Storm Other Operation and Maintenance Expense Regulatory Assets
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	3
WPCo Portion | Upfront Financing Costs
Regulatory Asset [Line Items]
Regulatory asset, requested to be financed through securitization	$ 6
Mitchell Plant ELG investments | Transource Energy
Regulatory Asset [Line Items]
Share of energy and capacity utilized by other party, percentage		50.00%
Mitchell Plant Non-ELG Capital Investments | Transource Energy
Regulatory Asset [Line Items]
Share of energy and capacity utilized by other party, percentage		50.00%
Mitchell Plant | Transource Energy
Regulatory Asset [Line Items]
Share of energy and capacity utilized by other party, percentage		50.00%