RATE MATTERS - Regulatory Assets Subject to Securitization (Details) - APPALACHIAN POWER COMPANY - USD ($) $ in Millions	Jul. 30, 2026	Jun. 30, 2026	Dec. 31, 2025
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		$ 2,708
Undepreciated Utility Plant Balances of Amos, Mitchell and Mountaineer (as of December 31, 2022)
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		1,704
ENEC Under-Recovery Regulatory Assets
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		593
ENEC Under-Recovery Regulatory Assets \| ENEC Filing \| Subsequent Event
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization	$ 2,700
Forecasted Undepreciated CCR and ELG Investments of Amos, Mitchell and Mountaineer (as of November 30, 2024)
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		237
Deferred Storm Other Operation and Maintenance Expense Regulatory Assets
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		158
Upfront Financing Costs
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		16
8/31/2026 Under-Recovery ENEC Balance \| ENEC Filing \| Subsequent Event
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization	593
APCo Portion
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		1,672
APCo Portion \| Undepreciated Utility Plant Balances of Amos, Mitchell and Mountaineer (as of December 31, 2022)
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		1,145
APCo Portion \| ENEC Under-Recovery Regulatory Assets
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		274
APCo Portion \| ENEC Under-Recovery Regulatory Assets \| ENEC Filing \| Subsequent Event
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization	1,700
APCo Portion \| Forecasted Undepreciated CCR and ELG Investments of Amos, Mitchell and Mountaineer (as of November 30, 2024)
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		88
APCo Portion \| Deferred Storm Other Operation and Maintenance Expense Regulatory Assets
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		155
APCo Portion \| Upfront Financing Costs
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		10
APCo Portion \| 8/31/2026 Under-Recovery ENEC Balance \| ENEC Filing \| Subsequent Event
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization	$ 274
WPCo Portion
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		1,036
WPCo Portion \| Undepreciated Utility Plant Balances of Amos, Mitchell and Mountaineer (as of December 31, 2022)
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		559
WPCo Portion \| ENEC Under-Recovery Regulatory Assets
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		319
WPCo Portion \| Forecasted Undepreciated CCR and ELG Investments of Amos, Mitchell and Mountaineer (as of November 30, 2024)
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		149
WPCo Portion \| Deferred Storm Other Operation and Maintenance Expense Regulatory Assets
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		3
WPCo Portion \| Upfront Financing Costs
Regulatory Asset [Line Items]
Regulatory asset, approved to be financed through securitization		$ 6
Mitchell Plant ELG investments \| KPCo
Regulatory Asset [Line Items]
Share of energy and capacity utilized by other party, percentage			50.00%
Mitchell Plant Non-ELG Capital Investments \| KPCo
Regulatory Asset [Line Items]
Share of energy and capacity utilized by other party, percentage			50.00%
Mitchell Plant \| KPCo
Regulatory Asset [Line Items]
Share of energy and capacity utilized by other party, percentage			50.00%