FINANCING ACTIVITIES - Debt Covenants Narrative (Details) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
	Feb. 12, 2026	Jan. 31, 2026	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Debt retired			$ 3,649	$ 2,685	$ 2,196
AEPTCo
Debt Instrument [Line Items]
Debt retired			102	95	60
Sub-limit of secured debt			$ 50
Maximum percentage of consolidated tangible net assets			10.00%
Tangible capital to tangible assets			0.009
INDIANA MICHIGAN POWER COMPANY
Debt Instrument [Line Items]
Debt retired			$ 300	103	343
INDIANA MICHIGAN POWER COMPANY | Notes Payable - Nonaffiliated | Subsequent Event
Debt Instrument [Line Items]
Debt retired		$ 11
APPALACHIAN POWER COMPANY
Debt Instrument [Line Items]
Debt retired			548	414	27
APPALACHIAN POWER COMPANY | Subsequent Event
Debt Instrument [Line Items]
Proceeds from contributed capital	$ 81
OHIO POWER COMPANY | Subsequent Event
Debt Instrument [Line Items]
Proceeds from contributed capital	38
SOUTHWESTERN ELECTRIC POWER COMPANY
Debt Instrument [Line Items]
Debt retired			11	0	94
SOUTHWESTERN ELECTRIC POWER COMPANY | Subsequent Event
Debt Instrument [Line Items]
Proceeds from contributed capital	$ 128
AEP TEXAS INC.
Debt Instrument [Line Items]
Debt retired			$ 724	$ 296	$ 279