EFFECTS OF REGULATION - Regulatory Liabilities - APCo (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Regulatory Liability [Line Items]
Total Current Regulatory Liabilities	$ 64	$ 54
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	8,362	8,344
Pending final regulatory determination
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	119	322
Approved for payment
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	8,243	8,022
Does not pay/paying a return | Over-recovered Fuel Costs
Regulatory Liability [Line Items]
Total Current Regulatory Liabilities	$ 10	32
Remaining Refund Period	1 year
Does not pay/paying a return | Pending final regulatory determination
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 29	146
Does not pay/paying a return | Pending final regulatory determination | FERC 2021 Transmission Formula Rate Challenge Refunds
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	0	131
Does not pay/paying a return | Pending final regulatory determination | Other Regulatory Liabilities Pending Final Regulatory Determination
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	29	15
Does not pay/paying a return | Approved for payment
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 3,047	2,496
Does not pay/paying a return | Approved for payment | 2017-2019 Virginia Triennial Revenue Provision
Regulatory Liability [Line Items]
Remaining Refund Period	24 years
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 33	35
Does not pay/paying a return | Approved for payment | Other Regulatory Liabilities Approved for Payment
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	125	79
Pays/paying a return | Over-recovered Fuel Costs
Regulatory Liability [Line Items]
Total Current Regulatory Liabilities	$ 54	22
Remaining Refund Period	1 year
Pays/paying a return | Pending final regulatory determination
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 90	176
Pays/paying a return | Pending final regulatory determination | Income Taxes, Net
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	90	176
Pays/paying a return | Approved for payment
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	5,196	5,526
Pays/paying a return | Approved for payment | Income Taxes, Net
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	1,048	1,622
Regulatory liabilities, not subject to rate normalization requirements, amount	$ 269	192
Regulatory liabilities, not subject to rate normalization requirements, refund period	8 years
Pays/paying a return | Approved for payment | Asset Removal Costs
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 4,023	3,828
Pays/paying a return | Approved for payment | Other Regulatory Liabilities Approved for Payment
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	39	40
APPALACHIAN POWER COMPANY
Regulatory Liability [Line Items]
Total Current Regulatory Liabilities	0	22
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	1,111	1,116
APPALACHIAN POWER COMPANY | Pending final regulatory determination
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	3	19
APPALACHIAN POWER COMPANY | Approved for payment
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	1,108	1,097
APPALACHIAN POWER COMPANY | Does not pay/paying a return | Over-recovered Fuel Costs
Regulatory Liability [Line Items]
Total Current Regulatory Liabilities	$ 0	22
Remaining Refund Period	1 year
APPALACHIAN POWER COMPANY | Does not pay/paying a return | Pending final regulatory determination
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 3	25
APPALACHIAN POWER COMPANY | Does not pay/paying a return | Pending final regulatory determination | FERC 2021 Transmission Formula Rate Challenge Refunds
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	0	25
APPALACHIAN POWER COMPANY | Does not pay/paying a return | Pending final regulatory determination | Other Regulatory Liabilities Pending Final Regulatory Determination
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	3	0
APPALACHIAN POWER COMPANY | Does not pay/paying a return | Approved for payment
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 115	72
APPALACHIAN POWER COMPANY | Does not pay/paying a return | Approved for payment | Unrealized Loss on Forward Commitments
Regulatory Liability [Line Items]
Remaining Refund Period	3 years
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 34	8
APPALACHIAN POWER COMPANY | Does not pay/paying a return | Approved for payment | 2017-2019 Virginia Triennial Revenue Provision
Regulatory Liability [Line Items]
Remaining Refund Period	24 years
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 33	35
APPALACHIAN POWER COMPANY | Does not pay/paying a return | Approved for payment | Virginia Environmental Rate Adjustment Clause
Regulatory Liability [Line Items]
Remaining Refund Period	2 years
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 18	10
APPALACHIAN POWER COMPANY | Does not pay/paying a return | Approved for payment | Energy Efficiency Rate Adjustment Clause - Virginia
Regulatory Liability [Line Items]
Remaining Refund Period	2 years
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 16	10
APPALACHIAN POWER COMPANY | Does not pay/paying a return | Approved for payment | West Virginia Environmental Compliance Surcharge
Regulatory Liability [Line Items]
Remaining Refund Period	2 years
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 11	0
APPALACHIAN POWER COMPANY | Does not pay/paying a return | Approved for payment | Other Regulatory Liabilities Approved for Payment
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	3	9
APPALACHIAN POWER COMPANY | Pays/paying a return | Pending final regulatory determination
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	0	(6)
APPALACHIAN POWER COMPANY | Pays/paying a return | Pending final regulatory determination | Income Taxes, Net
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	0	(6)
APPALACHIAN POWER COMPANY | Pays/paying a return | Approved for payment
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	993	1,025
APPALACHIAN POWER COMPANY | Pays/paying a return | Approved for payment | Income Taxes, Net
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	162	219
Regulatory liabilities, not subject to rate normalization requirements, amount	$ 11	12
Regulatory liabilities, not subject to rate normalization requirements, refund period	3 years
APPALACHIAN POWER COMPANY | Pays/paying a return | Approved for payment | Asset Removal Costs
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 831	$ 806