BUSINESS SEGMENTS - Schedule of AEP's Reportable Segment Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Revenues from:
Total Revenues	$ 6,020	$ 5,463
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	2,118	1,853
Other Operation and Maintenance	1,161	1,071
Asset Impairments and Other Related Charges	31	0
Depreciation and Amortization	907	833
Taxes Other Than Income Taxes	443	422
Allowance for Equity Funds Used During Construction	70	57
Interest Expense	552	495
Income Tax Expense (Benefit)	44	125
Equity Earnings of Unconsolidated Subsidiaries	25	38
Other Segment Items	(15)	(41)
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	874	800
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	874	800
Gross Property Additions	3,795	2,100
Total Assets	117,776		$ 114,460
Investments in Equity Method Investees	1,299		1,252
Nonrelated Party
Revenues from:
Total Revenues	6,020	5,463
Related Party
Revenues from:
Total Revenues	0	0
Operating Segments
Revenues from:
Total Revenues	6,599	5,954
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	2,200	1,921
Other Operation and Maintenance	1,659	1,528
Asset Impairments and Other Related Charges	31
Depreciation and Amortization	912	838
Taxes Other Than Income Taxes	435	415
Allowance for Equity Funds Used During Construction	70	57
Interest Expense	420	371
Income Tax Expense (Benefit)	81	182
Equity Earnings of Unconsolidated Subsidiaries	25	25
Other Segment Items	(27)	(45)
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	983	826
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	983	826
Gross Property Additions	3,642	2,059
Total Assets	116,882		112,772
Investments in Equity Method Investees	1,103		1,081
Operating Segments | Nonrelated Party
Revenues from:
Total Revenues	6,017	5,447
Operating Segments | Related Party
Revenues from:
Total Revenues	582	507
Corporate and Other
Revenues from:
Total Revenues	31	44
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	0	0
Other Operation and Maintenance	38	16
Asset Impairments and Other Related Charges	0
Depreciation and Amortization	(5)	(5)
Taxes Other Than Income Taxes	0	1
Allowance for Equity Funds Used During Construction	0	0
Interest Expense	166	147
Income Tax Expense (Benefit)	(37)	(57)
Equity Earnings of Unconsolidated Subsidiaries	0	13
Other Segment Items	(22)	(19)
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	(109)	(26)
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	(109)	(26)
Gross Property Additions	147	30
Total Assets	6,451		6,733
Investments in Equity Method Investees	196		171
Corporate and Other | Nonrelated Party
Revenues from:
Total Revenues	3	16
Corporate and Other | Related Party
Revenues from:
Total Revenues	28	28
Reconciling Adjustments
Revenues from:
Total Revenues	(610)	(535)
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	(82)	(68)
Other Operation and Maintenance	(536)	(473)
Asset Impairments and Other Related Charges	0
Depreciation and Amortization	0	0
Taxes Other Than Income Taxes	8	6
Allowance for Equity Funds Used During Construction	0	0
Interest Expense	(34)	(23)
Income Tax Expense (Benefit)	0	0
Equity Earnings of Unconsolidated Subsidiaries	0	0
Other Segment Items	34	23
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	0	0
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	0	0
Gross Property Additions	6	11
Total Assets	(5,557)		(5,045)
Investments in Equity Method Investees	0		0
Reconciling Adjustments | Nonrelated Party
Revenues from:
Total Revenues	0	0
Reconciling Adjustments | Related Party
Revenues from:
Total Revenues	(610)	(535)
VIU | Operating Segments
Revenues from:
Total Revenues	3,440	3,138
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	1,075	1,075
Other Operation and Maintenance	1,017	884
Asset Impairments and Other Related Charges	31
Depreciation and Amortization	559	515
Taxes Other Than Income Taxes	144	134
Allowance for Equity Funds Used During Construction	23	16
Interest Expense	245	200
Income Tax Expense (Benefit)	(48)	45
Equity Earnings of Unconsolidated Subsidiaries	0	0
Other Segment Items	(22)	(23)
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	462	324
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	462	324
Gross Property Additions	2,143	921
Total Assets	63,757		61,778
Investments in Equity Method Investees	9		9
VIU | Operating Segments | Nonrelated Party
Revenues from:
Total Revenues	3,365	3,086
VIU | Operating Segments | Related Party
Revenues from:
Total Revenues	75	52
T&D | Operating Segments
Revenues from:
Total Revenues	1,609	1,527
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	271	263
Other Operation and Maintenance	580	577
Asset Impairments and Other Related Charges	0
Depreciation and Amortization	217	203
Taxes Other Than Income Taxes	200	205
Allowance for Equity Funds Used During Construction	25	19
Interest Expense	105	112
Income Tax Expense (Benefit)	40	34
Equity Earnings of Unconsolidated Subsidiaries	0	1
Other Segment Items	(16)	(12)
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	237	165
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	237	165
Gross Property Additions	1,061	704
Total Assets	30,250		29,272
Investments in Equity Method Investees	4		4
T&D | Operating Segments | Nonrelated Party
Revenues from:
Total Revenues	1,594	1,515
T&D | Operating Segments | Related Party
Revenues from:
Total Revenues	15	12
AEPTHCo | Operating Segments
Revenues from:
Total Revenues	598	542
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	0	0
Other Operation and Maintenance	53	37
Asset Impairments and Other Related Charges	0
Depreciation and Amortization	131	116
Taxes Other Than Income Taxes	90	75
Allowance for Equity Funds Used During Construction	22	22
Interest Expense	69	57
Income Tax Expense (Benefit)	67	67
Equity Earnings of Unconsolidated Subsidiaries	25	24
Other Segment Items	26	1
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	209	235
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	209	235
Gross Property Additions	433	430
Total Assets	20,277		19,719
Investments in Equity Method Investees	1,090		1,068
AEPTHCo | Operating Segments | Nonrelated Party
Revenues from:
Total Revenues	127	116
AEPTHCo | Operating Segments | Related Party
Revenues from:
Total Revenues	471	426
G&M | Operating Segments
Revenues from:
Total Revenues	952	747
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	854	583
Other Operation and Maintenance	9	30
Asset Impairments and Other Related Charges	0
Depreciation and Amortization	5	4
Taxes Other Than Income Taxes	1	1
Allowance for Equity Funds Used During Construction	0	0
Interest Expense	1	2
Income Tax Expense (Benefit)	22	36
Equity Earnings of Unconsolidated Subsidiaries	0	0
Other Segment Items	(15)	(11)
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	75	102
EARNINGS ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	75	102
Gross Property Additions	5	4
Total Assets	2,598		2,003
Investments in Equity Method Investees	0		$ 0
G&M | Operating Segments | Nonrelated Party
Revenues from:
Total Revenues	931	730
G&M | Operating Segments | Related Party
Revenues from:
Total Revenues	$ 21	$ 17