VARIABLE INTEREST ENTITIES AND EQUITY METHOD INVESTMENTS - VIE Consolidation (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
ASSETS
Current Assets	$ 6,052	$ 5,789
Net Property, Plant and Equipment	92,374	82,416
Other Noncurrent Assets	16,034	14,873
TOTAL ASSETS	114,460	103,078
LIABILITIES AND EQUITY
Current Liabilities	13,314	13,009
Noncurrent Liabilities	68,890	63,045
Equity	32,218	26,986	$ 25,286	$ 24,123
TOTAL LIABILITIES AND EQUITY	114,460	103,078
SWEPCo
ASSETS
Current Assets	556	438
Net Property, Plant and Equipment	11,341	9,446
Other Noncurrent Assets	1,627	1,611
TOTAL ASSETS	13,524	11,495
LIABILITIES AND EQUITY
Current Liabilities	1,885	1,032
Noncurrent Liabilities	6,740	6,558
Equity	4,899	3,905	$ 3,770	$ 3,675
TOTAL LIABILITIES AND EQUITY	13,524	11,495
I&M
ASSETS
Current Assets	784	544
Net Property, Plant and Equipment	7,944	7,679
Other Noncurrent Assets	5,897	5,313
TOTAL ASSETS	14,625	13,536
LIABILITIES AND EQUITY
Current Liabilities	949	1,071
Noncurrent Liabilities	9,892	9,068
TOTAL LIABILITIES AND EQUITY	14,625	13,536
AEP Texas
ASSETS
Current Assets	509	500
Net Property, Plant and Equipment	15,864	14,044
Other Noncurrent Assets	702	656
TOTAL ASSETS	17,075	15,200
LIABILITIES AND EQUITY
Current Liabilities	1,418	1,407
Noncurrent Liabilities	9,831	8,908
TOTAL LIABILITIES AND EQUITY	17,075	15,200
APCo
ASSETS
Current Assets	1,033	1,095
Net Property, Plant and Equipment	14,713	13,613
Other Noncurrent Assets	2,046	1,958
TOTAL ASSETS	17,792	16,666
LIABILITIES AND EQUITY
Current Liabilities	2,384	2,026
Noncurrent Liabilities	9,228	8,892
TOTAL LIABILITIES AND EQUITY	17,792	16,666
Variable Interest Entity, Primary Beneficiary | AEP Credit
ASSETS
Current Assets	1,232	1,118
Net Property, Plant and Equipment	0	0
Other Noncurrent Assets	10	11
TOTAL ASSETS	1,242	1,129
LIABILITIES AND EQUITY
Current Liabilities	1,176	1,069
Noncurrent Liabilities	1	1
Equity	65	59
TOTAL LIABILITIES AND EQUITY	1,242	1,129
Variable Interest Entity, Primary Beneficiary | Protected Cell of EIS
ASSETS
Current Assets	223	219
Net Property, Plant and Equipment	0	0
Other Noncurrent Assets	0	0
TOTAL ASSETS	223	219
LIABILITIES AND EQUITY
Current Liabilities	56	55
Noncurrent Liabilities	102	96
Equity	65	68
TOTAL LIABILITIES AND EQUITY	223	219
Variable Interest Entity, Primary Beneficiary | Transource Energy
ASSETS
Current Assets	45	40
Net Property, Plant and Equipment	658	598
Other Noncurrent Assets	4	4
TOTAL ASSETS	707	642
LIABILITIES AND EQUITY
Current Liabilities	50	57
Noncurrent Liabilities	298	274
Equity	359	311
TOTAL LIABILITIES AND EQUITY	707	642
Variable Interest Entity, Primary Beneficiary | SWEPCo | Sabine
ASSETS
Current Assets	1	6
Net Property, Plant and Equipment	0	0
Other Noncurrent Assets	80	111
TOTAL ASSETS	81	117
LIABILITIES AND EQUITY
Current Liabilities	15	20
Noncurrent Liabilities	66	96
Equity	0	1
TOTAL LIABILITIES AND EQUITY	81	117
Variable Interest Entity, Primary Beneficiary | SWEPCo | SWEPCo Storm Recovery Funding
ASSETS
Current Assets	17
Net Property, Plant and Equipment	0
Other Noncurrent Assets	312
TOTAL ASSETS	329
LIABILITIES AND EQUITY
Current Liabilities	23
Noncurrent Liabilities	304
Equity	2
TOTAL LIABILITIES AND EQUITY	329
Variable Interest Entity, Primary Beneficiary | I&M | DCC Fuel
ASSETS
Current Assets	118	79
Net Property, Plant and Equipment	227	132
Other Noncurrent Assets	118	64
TOTAL ASSETS	463	275
LIABILITIES AND EQUITY
Current Liabilities	118	79
Noncurrent Liabilities	345	196
Equity	0	0
TOTAL LIABILITIES AND EQUITY	463	275
Variable Interest Entity, Primary Beneficiary | AEP Texas | AEP Texas Transition Funding | Intersegment Eliminations
ASSETS
Other Noncurrent Assets	(4)	(5)
Variable Interest Entity, Primary Beneficiary | AEP Texas | AEP Texas Restoration Funding
ASSETS
Current Assets	18	21
Net Property, Plant and Equipment	0	0
Other Noncurrent Assets	98	122
TOTAL ASSETS	116	143
LIABILITIES AND EQUITY
Current Liabilities	31	31
Noncurrent Liabilities	84	111
Equity	1	1
TOTAL LIABILITIES AND EQUITY	116	143
Variable Interest Entity, Primary Beneficiary | AEP Texas | AEP Texas Restoration Funding | Intersegment Eliminations
ASSETS
Other Noncurrent Assets	(1)	(1)
Variable Interest Entity, Primary Beneficiary | APCo | APCo Appalachian Consumer Rate Relief Funding
ASSETS
Current Assets	18	14
Net Property, Plant and Equipment	0	0
Other Noncurrent Assets	79	110
TOTAL ASSETS	97	124
LIABILITIES AND EQUITY
Current Liabilities	31	31
Noncurrent Liabilities	64	91
Equity	2	2
TOTAL LIABILITIES AND EQUITY	97	124
Variable Interest Entity, Primary Beneficiary | KPCo | SWEPCo Storm Recovery Funding
ASSETS
Current Assets	24	3
Net Property, Plant and Equipment	0	0
Other Noncurrent Assets	462	332
TOTAL ASSETS	486	335
LIABILITIES AND EQUITY
Current Liabilities	30	24
Noncurrent Liabilities	454	309
Equity	2	2
TOTAL LIABILITIES AND EQUITY	486	$ 335
Variable Interest Entity, Primary Beneficiary | KPCo | SWEPCo Storm Recovery Funding | Intersegment Eliminations
ASSETS
Other Noncurrent Assets	$ (16)