EFFECTS OF REGULATION - Regulatory Liabilities - OPCo (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Regulatory Liability [Line Items]
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]
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 | 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 | 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]
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
OHIO POWER COMPANY
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	893	988
OHIO POWER COMPANY | Pending final regulatory determination
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	77	73
OHIO POWER COMPANY | Approved for payment
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	816	915
OHIO 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	0	73
OHIO 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	73
OHIO POWER COMPANY | Does not pay/paying a return | Approved for payment
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	74	63
OHIO 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	13	8
OHIO POWER COMPANY | Does not pay/paying a return | Approved for payment | Over-recovered Fuel Costs
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 38	32
Remaining Refund Period	7 years
OHIO POWER COMPANY | Does not pay/paying a return | Approved for payment | Peak Demand Reduction/Energy Efficiency
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 23	23
Remaining Refund Period	2 years
OHIO POWER COMPANY | Pays/paying a return | Approved for payment
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 742	852
OHIO 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	271	368
Regulatory liabilities, not subject to rate normalization requirements, amount	$ 14	100
Regulatory liabilities, not subject to rate normalization requirements, refund period	2 years
OHIO 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	$ 470	480
OHIO POWER COMPANY | 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	1	4
OHIO POWER COMPANY | Earns/earning a return | Pending final regulatory approval
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	77	0
OHIO POWER COMPANY | Earns/earning a return | Pending final regulatory approval | Income Taxes, Net
Regulatory Liability [Line Items]
Total Noncurrent Regulatory Liabilities and Deferred Investment Tax Credits	$ 77	$ 0