Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal Statutory Rate	21.00%	21.00%	21.00%	21.00%
State Income Tax, net of Federal benefit	2.70%	2.00%	2.60%	2.10%
Tax Reform Excess ADIT Reversal	(16.40%)	(30.70%)	(12.80%)	(20.40%)
Production and Investment Tax Credits	(4.60%)	(5.50%)	(4.40%)	(3.50%)
Flow Through	0.50%	(0.20%)	0.50%	(0.10%)
AFUDC Equity	(1.50%)	(1.40%)	(1.50%)	(1.40%)
Parent Company Loss Benefit	0.00%	0.00%	0.00%	0.00%
Discrete Tax Adjustments		0.20%	0.00%	1.10%
Other	0.70%	1.10%	0.10%	0.20%
Effective Income Tax Rate	2.40%	(13.50%)	5.50%	(1.00%)
Income Taxes (Textuals) [Abstract]
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	$ 20		$ 20
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 Income Tax, net of Federal benefit	1.80%	1.50%	1.70%	1.50%
Tax Reform Excess ADIT Reversal	(57.90%)	(243.40%)	(30.40%)	(98.80%)
Production and Investment Tax Credits	(0.50%)	(1.00%)	(0.40%)	(1.00%)
Flow Through	0.20%	0.30%	0.10%	0.30%
AFUDC Equity	(3.30%)	(1.60%)	(2.90%)	(1.60%)
Parent Company Loss Benefit	0.20%	(2.30%)	0.00%	(2.30%)
Discrete Tax Adjustments		(8.40%)	0.00%	(3.20%)
Other	0.00%	(0.50%)	0.10%	0.10%
Effective Income Tax Rate	(38.50%)	(234.40%)	(10.80%)	(84.00%)
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 Income Tax, net of Federal benefit	2.90%	2.90%	2.90%	2.90%
Tax Reform Excess ADIT Reversal	0.40%	0.40%	0.40%	0.40%
Production and Investment Tax Credits	0.00%	0.00%	0.00%	0.00%
Flow Through	0.50%	0.20%	0.50%	0.20%
AFUDC Equity	(2.60%)	(2.50%)	(2.60%)	(2.50%)
Parent Company Loss Benefit	(0.80%)	(0.90%)	(0.90%)	(0.90%)
Discrete Tax Adjustments		(1.50%)	0.00%	(0.80%)
Other	(0.60%)	(0.10%)	(0.20%)	(0.20%)
Effective Income Tax Rate	20.80%	19.50%	21.10%	20.10%
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 Income Tax, net of Federal benefit	3.20%	3.50%	3.10%	3.50%
Tax Reform Excess ADIT Reversal	(32.50%)	(71.60%)	(20.20%)	(49.50%)
Production and Investment Tax Credits	0.00%	0.00%	0.00%	0.00%
Flow Through	1.90%	(1.00%)	1.60%	(0.90%)
AFUDC Equity	(1.30%)	(1.10%)	(1.10%)	(1.00%)
Parent Company Loss Benefit	(2.90%)	(2.80%)	(3.10%)	(2.50%)
Discrete Tax Adjustments		0.00%	0.00%	0.30%
Other	(0.20%)	(0.10%)	0.00%	(0.40%)
Effective Income Tax Rate	(10.80%)	(52.10%)	1.30%	(29.50%)
Income Taxes (Textuals) [Abstract]
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	$ 7		$ 7
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 Income Tax, net of Federal benefit	3.60%	2.00%	3.40%	2.00%
Tax Reform Excess ADIT Reversal	(12.60%)	(17.40%)	(16.70%)	(17.40%)
Production and Investment Tax Credits	(1.20%)	(1.90%)	(1.60%)	(1.90%)
Flow Through	0.10%	(2.40%)	0.20%	(2.40%)
AFUDC Equity	(0.70%)	(1.90%)	(0.90%)	(1.90%)
Parent Company Loss Benefit	(3.30%)	(1.80%)	(3.70%)	(1.80%)
Discrete Tax Adjustments		2.70%	1.60%	1.00%
Other	0.00%	(0.50%)	(0.10%)	(0.40%)
Effective Income Tax Rate	6.90%	(0.20%)	3.20%	(1.80%)
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 Income Tax, net of Federal benefit	0.70%	0.90%	0.70%	0.90%
Tax Reform Excess ADIT Reversal	(9.30%)	(7.60%)	(9.70%)	(7.60%)
Production and Investment Tax Credits	0.00%	0.00%	0.00%	0.00%
Flow Through	0.90%	0.70%	0.90%	0.70%
AFUDC Equity	(0.80%)	(0.70%)	(0.90%)	(0.70%)
Parent Company Loss Benefit	(0.40%)	(1.10%)	(0.30%)	(1.10%)
Discrete Tax Adjustments		3.20%	0.00%	0.90%
Other	0.10%	0.00%	0.10%	0.20%
Effective Income Tax Rate	12.20%	16.40%	11.80%	14.30%
Income Taxes (Textuals) [Abstract]
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	$ 9		$ 9
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 Income Tax, net of Federal benefit	4.60%	4.60%	4.60%	4.60%
Tax Reform Excess ADIT Reversal	(20.90%)	(21.90%)	(20.30%)	(21.90%)
Production and Investment Tax Credits	(1.20%)	(1.70%)	(1.10%)	(1.70%)
Flow Through	0.30%	0.60%	0.20%	0.60%
AFUDC Equity	(0.60%)	(0.40%)	(0.60%)	(0.40%)
Parent Company Loss Benefit	(1.80%)	(1.80%)	(1.70%)	(1.80%)
Discrete Tax Adjustments		0.00%	0.00%	0.00%
Other	0.10%	0.30%	0.10%	0.20%
Effective Income Tax Rate	1.50%	0.70%	2.20%	0.60%
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 Income Tax, net of Federal benefit	2.10%	0.10%	2.20%	0.20%
Tax Reform Excess ADIT Reversal	(6.30%)	(12.70%)	(17.00%)	(16.20%)
Production and Investment Tax Credits	(0.40%)	(0.60%)	(0.40%)	(0.80%)
Flow Through	(1.20%)	(0.70%)	(1.10%)	(0.90%)
AFUDC Equity	(0.30%)	(0.80%)	(0.30%)	(1.00%)
Parent Company Loss Benefit	(1.70%)	(0.40%)	(1.80%)	(0.50%)
Discrete Tax Adjustments		(5.90%)	0.00%	(1.10%)
Other	(1.30%)	0.00%	(0.30%)	1.30%
Effective Income Tax Rate	11.90%	0.00%	2.30%	2.00%