Income Taxes (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
	Apr. 30, 2024	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%	21.00%
State Income Tax, net of Federal Benefit		2.10%	1.90%
Tax Reform Excess ADIT Reversal		(2.30%)	(6.20%)
Remeasurement of Excess ADIT		(29.70%)
Production and Investment Tax Credits		(6.80%)	(9.70%)
Flow Through		0.00%	0.10%
AFUDC Equity		(1.20%)	(1.40%)
Discrete Tax Adjustments		0.20%	(3.20%)
Other		0.20%	0.10%
Effective Income Tax Rate		(16.50%)	2.60%
Income Taxes (Textuals) [Abstract]
corporate alternative minimum tax		15.00%
Production Tax Credit Proceeds	$ 10.0	$ 62.0		$ 102.0
AEP Texas Inc. [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%	21.00%
State Income Tax, net of Federal Benefit		0.20%	0.30%
Tax Reform Excess ADIT Reversal		(1.30%)	(1.50%)
Remeasurement of Excess ADIT		0.00%
Production and Investment Tax Credits		(0.20%)	(0.20%)
Flow Through		0.10%	0.20%
AFUDC Equity		(1.50%)	(1.50%)
Discrete Tax Adjustments		0.00%	0.00%
Other		0.50%	0.10%
Effective Income Tax Rate		18.80%	18.40%
AEP Transmission Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%	21.00%
State Income Tax, net of Federal Benefit		2.60%	2.60%
Tax Reform Excess ADIT Reversal		0.20%	0.30%
Remeasurement of Excess ADIT		0.00%
Production and Investment Tax Credits		0.00%	0.00%
Flow Through		0.30%	0.30%
AFUDC Equity		(1.80%)	(1.60%)
Discrete Tax Adjustments		0.00%	0.00%
Other		0.00%	0.10%
Effective Income Tax Rate		22.30%	22.70%
Appalachian Power Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%	21.00%
State Income Tax, net of Federal Benefit		2.40%	2.40%
Tax Reform Excess ADIT Reversal		(13.40%)	(4.60%)
Remeasurement of Excess ADIT		0.00%
Production and Investment Tax Credits		(0.10%)	0.00%
Flow Through		(0.30%)	0.60%
AFUDC Equity		(0.40%)	(0.70%)
Discrete Tax Adjustments		0.00%	3.20%
Other		0.10%	0.00%
Effective Income Tax Rate		9.30%	21.90%
Indiana Michigan Power Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%	21.00%
State Income Tax, net of Federal Benefit		3.90%	3.60%
Tax Reform Excess ADIT Reversal		(0.50%)	(7.90%)
Remeasurement of Excess ADIT		(58.20%)
Production and Investment Tax Credits		(1.10%)	(1.10%)
Flow Through		(2.80%)	(1.80%)
AFUDC Equity		(0.70%)	(0.50%)
Discrete Tax Adjustments		0.00%	1.80%
Other		0.00%	0.00%
Effective Income Tax Rate		(38.40%)	15.10%
Income Taxes (Textuals) [Abstract]
Tax Benefit Recognized from the Reduction in Excess ADIT Resulting from IRS PLR Received		$ 61.0
Ohio Power Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%	21.00%
State Income Tax, net of Federal Benefit		1.00%	1.00%
Tax Reform Excess ADIT Reversal		(6.00%)	(6.80%)
Remeasurement of Excess ADIT		0.00%
Production and Investment Tax Credits		0.00%	0.00%
Flow Through		0.60%	0.50%
AFUDC Equity		(1.00%)	(0.80%)
Discrete Tax Adjustments		0.00%	0.00%
Other		0.20%	0.00%
Effective Income Tax Rate		15.80%	14.90%
Public Service Co Of Oklahoma [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate		21.00%	21.00%
State Income Tax, net of Federal Benefit		3.70%	3.20%
Tax Reform Excess ADIT Reversal		(2.00%)	(18.70%)
Remeasurement of Excess ADIT		(263.30%)
Production and Investment Tax Credits		(49.60%)	(55.70%)
Flow Through		0.20%	0.30%
AFUDC Equity		(1.30%)	(1.40%)
Discrete Tax Adjustments		0.90%	0.00%
Other		1.20%	(2.00%)
Effective Income Tax Rate		(289.20%)	(53.30%)
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%
State Income Tax, net of Federal Benefit		1.70%	(0.40%)
Tax Reform Excess ADIT Reversal		4.60%	(3.80%)
Remeasurement of Excess ADIT		(224.70%)
Production and Investment Tax Credits		(23.80%)	(26.40%)
Flow Through		0.60%	0.50%
AFUDC Equity		(1.30%)	(0.80%)
Discrete Tax Adjustments		1.30%	0.00%
Other		(0.80%)	(0.80%)
Effective Income Tax Rate		(221.40%)	(10.70%)
Income Taxes (Textuals) [Abstract]
Tax Benefit Recognized from the Reduction in Excess ADIT Resulting from IRS PLR Received		$ 114.0