Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended					9 Months Ended		12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%			21.00%	21.00%	21.00%
State and Local Income Taxes, Net		0.60%			1.40%	1.20%	1.70%
Tax Reform Excess ADIT Reversal		(2.80%)			(5.70%)	(3.10%)	(6.00%)
Remeasurement of Excess ADIT						(11.90%)
Production and Investment Tax Credits		(9.90%)			(5.10%)	(8.30%)	(7.40%)
Reversal of Origination Flow-Through		0.10%			0.10%	0.20%	(0.20%)
AFUDC Equity		(1.50%)			(1.40%)	(1.60%)	(1.40%)
Discrete Tax Adjustments		(3.70%)			(4.10%)	(2.10%)	(2.80%)
Other		0.00%			0.10%	0.20%	0.30%
Effective Income Tax Rate		3.80%			6.30%	(4.40%)	5.20%
Income Taxes (Textuals) [Abstract]
corporate alternative minimum tax						15.00%
Production Tax Credit Proceeds	$ 46.0	$ 91.0	$ 10.0	$ 62.0				$ 102.0
Production Tax Credits Sold						$ 137.0		$ 174.0
AEP Texas Inc. [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%			21.00%	21.00%	21.00%
State and Local Income Taxes, Net		0.30%			0.50%	0.40%	0.50%
Tax Reform Excess ADIT Reversal		(1.00%)			(1.30%)	(1.10%)	(1.30%)
Remeasurement of Excess ADIT						1.50%
Production and Investment Tax Credits		0.00%			0.10%	(0.10%)	0.00%
Reversal of Origination Flow-Through		0.10%			0.20%	0.10%	0.20%
AFUDC Equity		(2.30%)			(1.40%)	(1.70%)	(1.20%)
Discrete Tax Adjustments		0.00%			0.00%	0.00%	0.00%
Other		0.20%			(0.50%)	0.00%	(0.20%)
Effective Income Tax Rate		18.30%			18.60%	20.10%	19.00%
AEP Transmission Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%			21.00%	21.00%	21.00%
State and Local Income Taxes, Net		2.50%			2.80%	2.50%	2.70%
Tax Reform Excess ADIT Reversal		0.20%			(0.20%)	0.20%	0.10%
Remeasurement of Excess ADIT						0.00%
Production and Investment Tax Credits		0.00%			0.00%	0.00%	0.00%
Reversal of Origination Flow-Through		0.30%			0.30%	0.30%	0.30%
AFUDC Equity		(1.90%)			(2.40%)	(2.00%)	(2.00%)
Discrete Tax Adjustments		0.00%			0.00%	0.00%	0.00%
Other		(0.20%)			(1.00%)	(0.10%)	(0.50%)
Effective Income Tax Rate		21.90%			20.50%	21.90%	21.60%
Appalachian Power Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%			21.00%	21.00%	21.00%
State and Local Income Taxes, Net		1.40%			2.20%	2.10%	2.40%
Tax Reform Excess ADIT Reversal		(2.30%)			(5.30%)	(7.10%)	(4.80%)
Remeasurement of Excess ADIT						0.00%
Production and Investment Tax Credits		(0.10%)			(0.10%)	(0.10%)	(0.10%)
Reversal of Origination Flow-Through		(1.10%)			1.80%	(0.80%)	0.10%
AFUDC Equity		(1.50%)			(1.50%)	(1.10%)	(1.20%)
Discrete Tax Adjustments		0.00%			0.00%	0.00%	1.50%
Other		(0.40%)			0.70%	(0.10%)	0.40%
Effective Income Tax Rate		17.00%			18.80%	13.90%	19.30%
Indiana Michigan Power Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%			21.00%	21.00%	21.00%
State and Local Income Taxes, Net		0.70%			2.10%	1.50%	2.30%
Tax Reform Excess ADIT Reversal		(7.90%)			(8.50%)	(5.70%)	(7.60%)
Remeasurement of Excess ADIT						(27.50%)
Production and Investment Tax Credits		(45.60%)			(0.70%)	(23.40%)	(0.60%)
Reversal of Origination Flow-Through		0.30%			0.70%	0.30%	(1.70%)
AFUDC Equity		(1.20%)			(0.50%)	(1.10%)	(0.40%)
Discrete Tax Adjustments		0.00%			0.00%	0.00%	0.70%
Other		0.00%			(3.50%)	0.00%	(1.20%)
Effective Income Tax Rate		(32.70%)			10.60%	(34.90%)	12.50%
Income Taxes (Textuals) [Abstract]
Tax Benefit Recognized from the Reduction in Excess ADIT Resulting from IRS PLR Received				61.0
Tax Benefit Recognized from the Nuclear Production Tax Credit		$ 61.0
Estimated Nuclear Production Tax Credit		$ 64.0
Ohio Power Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%			21.00%	21.00%	21.00%
State and Local Income Taxes, Net		1.10%			0.80%	0.90%	0.90%
Tax Reform Excess ADIT Reversal		(7.30%)			(6.80%)	(8.70%)	(7.30%)
Remeasurement of Excess ADIT						0.00%
Production and Investment Tax Credits		0.00%			0.00%	0.00%	0.00%
Reversal of Origination Flow-Through		0.70%			0.80%	0.80%	0.80%
AFUDC Equity		(1.20%)			(0.80%)	(1.30%)	(0.80%)
Discrete Tax Adjustments		0.00%			0.00%	0.00%	0.00%
Other		0.60%			1.30%	0.40%	0.50%
Effective Income Tax Rate		14.90%			16.30%	13.10%	15.10%
Public Service Co Of Oklahoma [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%			21.00%	21.00%	21.00%
State and Local Income Taxes, Net		0.00%			3.00%	0.00%	2.80%
Tax Reform Excess ADIT Reversal		(5.00%)			(17.00%)	(4.30%)	(17.10%)
Remeasurement of Excess ADIT						(40.50%)
Production and Investment Tax Credits		(61.90%)			(46.90%)	(61.70%)	(48.90%)
Reversal of Origination Flow-Through		0.30%			0.30%	0.30%	0.30%
AFUDC Equity		(1.30%)			(1.60%)	(1.30%)	(1.50%)
Discrete Tax Adjustments		0.00%			0.00%	1.20%	0.00%
Other		1.50%			(0.20%)	0.00%	(0.20%)
Effective Income Tax Rate		(45.40%)			(41.40%)	(85.30%)	(43.60%)
Income Taxes (Textuals) [Abstract]
Tax Benefit Recognized from the Reduction in Excess ADIT Resulting from IRS PLR Received				49.0
Southwestern Electric Power Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%			21.00%	21.00%	21.00%
State and Local Income Taxes, Net		(2.60%)			(4.30%)	(2.60%)	(2.90%)
Tax Reform Excess ADIT Reversal		(3.20%)			(6.20%)	(4.20%)	(5.30%)
Remeasurement of Excess ADIT						(181.80%)
Production and Investment Tax Credits		(23.40%)			(25.50%)	(79.10%)	(26.70%)
Reversal of Origination Flow-Through		0.60%			(0.20%)	2.10%	(0.30%)
AFUDC Equity		(0.50%)			(0.80%)	(2.30%)	(0.50%)
Discrete Tax Adjustments		0.00%			0.00%	1.10%	0.00%
Other		0.00%			0.20%	(0.50%)	0.20%
Effective Income Tax Rate		(8.10%)			(15.80%)	(246.30%)	(14.50%)
Income Taxes (Textuals) [Abstract]
Tax Benefit Recognized from the Reduction in Excess ADIT Resulting from IRS PLR Received				$ 114.0