BUSINESS SEGMENTS - Schedule of AEP's Reportable Segment Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Reportable Segment Information
Total Revenues	$ 5,463.4	$ 5,025.7
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	1,852.9	1,575.8
Other Operation and Maintenance	1,070.9	1,079.8
Depreciation and Amortization	833.4	787.1
Taxes Other Than Income Taxes	422.0	410.4
Allowance for Equity Funds Used During Construction	57.3	43.6
Interest Expense	494.9	435.6
Income Tax Expense (Benefit)	125.5	(141.9)
Equity Earnings of Unconsolidated Subsidiaries	38.2	24.5
Other Segment Items	(40.9)	(56.1)
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	800.2	1,003.1
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	800.2	1,003.1
Gross Property Additions	2,100.2	1,761.7
Assets	104,394.6		$ 103,078.0
Equity Method Investments	1,097.3		1,055.9
Related Party
Reportable Segment Information
Total Revenues	0.0	0.0
Operating Segments
Reportable Segment Information
Total Revenues	5,953.3	5,498.9
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	1,920.7	1,677.0
Other Operation and Maintenance	1,528.3	1,473.1
Depreciation and Amortization	838.4	792.4
Taxes Other Than Income Taxes	415.1	405.7
Allowance for Equity Funds Used During Construction	57.3	43.6
Interest Expense	371.1	316.3
Income Tax Expense (Benefit)	181.8	(95.3)
Equity Earnings of Unconsolidated Subsidiaries	24.8	23.9
Other Segment Items	(45.7)	(60.2)
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	825.7	1,057.4
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	825.7	1,057.4
Gross Property Additions	2,058.8	1,753.6
Assets	102,478.8		101,506.6
Equity Method Investments	1,030.9		1,007.2
Operating Segments | Nonrelated Party
Reportable Segment Information
Total Revenues	5,447.5	5,010.8
Operating Segments | Related Party
Reportable Segment Information
Total Revenues	505.8	488.1
Corporate and Other
Reportable Segment Information
Total Revenues	44.6	52.8
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	0.0	0.0
Other Operation and Maintenance	15.8	36.1
Depreciation and Amortization	(5.1)	(5.3)
Taxes Other Than Income Taxes	0.5	0.1
Allowance for Equity Funds Used During Construction	0.0	0.0
Interest Expense	147.0	155.8
Income Tax Expense (Benefit)	(56.3)	(46.6)
Equity Earnings of Unconsolidated Subsidiaries	13.4	0.6
Other Segment Items	(18.4)	(32.4)
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	(25.5)	(54.3)
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	(25.5)	(54.3)
Gross Property Additions	30.0	3.1
Assets	5,720.6		5,550.8
Equity Method Investments	66.3		48.7
Corporate and Other | Nonrelated Party
Reportable Segment Information
Total Revenues	15.9	14.9
Corporate and Other | Related Party
Reportable Segment Information
Total Revenues	28.7	37.9
Reconciling Adjustments
Reportable Segment Information
Total Revenues	(534.5)	(526.0)
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	(67.8)	(101.2)
Other Operation and Maintenance	(473.2)	(429.4)
Depreciation and Amortization	0.1	0.0
Taxes Other Than Income Taxes	6.4	4.6
Allowance for Equity Funds Used During Construction	0.0	0.0
Interest Expense	(23.2)	(36.5)
Income Tax Expense (Benefit)	0.0	0.0
Equity Earnings of Unconsolidated Subsidiaries	0.0	0.0
Other Segment Items	23.2	36.5
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	0.0	0.0
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	0.0	0.0
Gross Property Additions	11.4	5.0
Assets	(3,804.8)		(3,979.4)
Equity Method Investments	0.0		0.0
Reconciling Adjustments | Nonrelated Party
Reportable Segment Information
Total Revenues	0.0	0.0
Reconciling Adjustments | Related Party
Reportable Segment Information
Total Revenues	(534.5)	(526.0)
VIU | Operating Segments
Reportable Segment Information
Total Revenues	3,137.8	2,947.9
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	1,075.4	999.1
Other Operation and Maintenance	883.4	885.3
Depreciation and Amortization	515.2	453.6
Taxes Other Than Income Taxes	133.6	139.7
Allowance for Equity Funds Used During Construction	16.4	11.7
Interest Expense	200.7	157.2
Income Tax Expense (Benefit)	44.8	(206.2)
Equity Earnings of Unconsolidated Subsidiaries	0.3	0.4
Other Segment Items	(22.7)	(29.5)
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	324.1	560.8
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	324.1	560.8
Gross Property Additions	920.6	801.8
Assets	55,210.5		54,996.5
Equity Method Investments	9.0		9.1
VIU | Operating Segments | Nonrelated Party
Reportable Segment Information
Total Revenues	3,085.5	2,901.2
VIU | Operating Segments | Related Party
Reportable Segment Information
Total Revenues	52.3	46.7
T&D | Operating Segments
Reportable Segment Information
Total Revenues	1,526.5	1,490.2
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	262.8	305.3
Other Operation and Maintenance	577.1	519.2
Depreciation and Amortization	202.9	222.5
Taxes Other Than Income Taxes	205.2	190.8
Allowance for Equity Funds Used During Construction	18.5	14.1
Interest Expense	111.6	96.2
Income Tax Expense (Benefit)	33.8	31.5
Equity Earnings of Unconsolidated Subsidiaries	1.3	(0.1)
Other Segment Items	(11.7)	(11.6)
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	164.6	150.3
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	164.6	150.3
Gross Property Additions	704.0	572.3
Assets	27,073.7		26,864.3
Equity Method Investments	3.4		2.0
T&D | Operating Segments | Nonrelated Party
Reportable Segment Information
Total Revenues	1,515.5	1,483.2
T&D | Operating Segments | Related Party
Reportable Segment Information
Total Revenues	11.0	7.0
AEPTHCo | Operating Segments
Reportable Segment Information
Total Revenues	542.1	497.3
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	0.0	0.0
Other Operation and Maintenance	37.4	37.1
Depreciation and Amortization	116.2	108.1
Taxes Other Than Income Taxes	75.6	75.0
Allowance for Equity Funds Used During Construction	22.4	17.8
Interest Expense	56.9	56.9
Income Tax Expense (Benefit)	66.9	54.3
Equity Earnings of Unconsolidated Subsidiaries	23.2	22.7
Other Segment Items	0.1	(2.3)
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	234.6	208.7
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	234.6	208.7
Gross Property Additions	430.3	9.9
Assets	18,391.2		18,011.9
Equity Method Investments	1,018.5		996.1
AEPTHCo | Operating Segments | Nonrelated Party
Reportable Segment Information
Total Revenues	115.9	110.5
AEPTHCo | Operating Segments | Related Party
Reportable Segment Information
Total Revenues	426.2	386.8
G&M | Operating Segments
Reportable Segment Information
Total Revenues	746.9	563.5
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation	582.5	372.6
Other Operation and Maintenance	30.4	31.5
Depreciation and Amortization	4.1	8.2
Taxes Other Than Income Taxes	0.7	0.2
Allowance for Equity Funds Used During Construction	0.0	0.0
Interest Expense	1.9	6.0
Income Tax Expense (Benefit)	36.3	25.1
Equity Earnings of Unconsolidated Subsidiaries	0.0	0.9
Other Segment Items	(11.4)	(16.8)
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Basic	102.4	137.6
EARNINGS (LOSS) ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS, Diluted	102.4	137.6
Gross Property Additions	3.9	369.6
Assets	1,803.4		1,633.9
Equity Method Investments	0.0		$ 0.0
G&M | Operating Segments | Nonrelated Party
Reportable Segment Information
Total Revenues	730.6	515.9
G&M | Operating Segments | Related Party
Reportable Segment Information
Total Revenues	$ 16.3	$ 47.6