Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021		Dec. 31, 2020	Dec. 31, 2019
Federal:
Current	$ (27.8)		$ (138.2)	$ (7.4)
Deferred	182.6		146.9	(71.6)
Total Federal	154.8		8.7	(79.0)
Current	6.0		(16.7)	4.4
Deferred	(45.3)	[1]	48.5	61.7
Total State and Local	(39.3)		31.8	66.1
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	115.5		40.5	(12.9)
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	2,488.1		2,196.7	1,919.8
Less: Equity Earnings – Dolet Hills	(91.7)		(91.1)	(72.1)
Income Tax Expense (Benefit)	115.5		40.5	(12.9)
Pretax Income	2,600.2		2,234.3	1,903.9
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 546.0		$ 469.2	$ 399.8
Federal Statutory Income Tax Rate	21.00%		21.00%	21.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Depreciation	$ 25.9		$ 26.5	$ 20.4
Investment Tax Credit Amortization	(22.0)		(18.8)	(13.0)
Production Tax Credits	(98.8)		(83.1)	(59.6)
State and Local Income Taxes, Net	39.4		25.1	52.2
Removal Costs	(20.0)		(18.6)	(22.2)
AFUDC	(30.6)		(32.5)	(37.1)
Increase Decrease in Income Taxes Due to Tax Reserve Adjustments	(55.1)	[2]	0.0	0.0
Tax Reform Excess ADIT Reversal	(255.6)		(268.2)	(353.2)
CARES Act Provision	0.0		(48.0)	0.0
Other	(13.7)		(11.1)	(0.2)
Income Tax Expense (Benefit)	$ 115.5		$ 40.5	$ (12.9)
Effective Income Tax Rate	4.40%		1.80%	(0.70%)
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 3,277.0		$ 3,259.7
Deferred Tax Liabilities	(11,479.5)		(11,500.6)
Property Related Temporary Differences	(7,020.3)		(7,340.5)
Amounts Due from Customers for Future Federal Income Taxes	1,033.0		1,075.8
Deferred State Income Taxes	(1,116.7)		(1,317.6)
Securitized Assets	(128.8)		(140.0)
Regulatory Assets	(645.4)		(391.6)
Accrued Nuclear Decommissioning	(743.2)		(626.4)
Net Operating Loss Carryforward	285.7		112.9
Tax Credit Carryforward	439.8		323.6
Operating Lease Liability	114.2		183.7
Investment in Partnership	(392.1)		(362.0)
All Other, Net	(28.7)		241.2
Net Deferred Tax Liabilities	(8,202.5)		(8,240.9)
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	(674.0)
Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits
Balance at January 1,	13.2		24.1	$ 14.6
Increase - Tax Positions Taken During a Prior Period	1.2		0.6	8.8
Decrease - Tax Positions Taken During a Prior Period	(3.2)		(14.5)	(2.1)
Increase - Tax Positions Taken During the Current Year	3.1		3.0	2.8
Decrease - Tax Positions Taken During the Current Year	0.0		0.0	0.0
Decrease - Settlements with Taxing Authorities	0.0		0.0	0.0
Decrease - Lapse of the Applicable Statute of Limitations	0.0		0.0	0.0
Balance at December 31,	14.3		13.2	24.1
Tax Contingency [Abstract]
Unrecognized Tax Benefits, if Recognized - Amount	14.0		12.0	20.0
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	115.5		40.5	(12.9)
Income Taxes Receivable	95.0
Tax Cuts and Jobs Act, Change in Tax Rate, Deferred Tax Asset, Income Tax Expense	48.0
Income Tax Expense Re-Measurement	23.0
Operating Income (Loss)	$ (3,411.3)		(2,987.7)	(2,592.3)
Minimum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2036
Maximum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2040
AEP Texas Inc. [Member]
Federal:
Current	$ (1.2)		5.2	(31.8)
Deferred	40.5		(15.4)	(24.7)
Total Federal	39.3		(10.2)	(56.5)
Current	3.0		(0.1)	2.9
Deferred	0.8		(0.9)	0.0
Total State and Local	3.8		(1.0)	2.9
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	43.1		(11.2)	(53.6)
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	289.8		241.0	178.3
Income Tax Expense (Benefit)	43.1		(11.2)	(53.6)
Pretax Income	332.9		229.8	124.7
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 69.9		$ 48.3	$ 26.2
Federal Statutory Income Tax Rate	21.00%		21.00%	21.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
State and Local Income Taxes, Net	$ 2.4		$ (0.8)	$ 2.3
AFUDC	(4.5)		(4.1)	(3.2)
Parent Company Loss Benefit	(3.2)		(4.5)	(3.8)
Tax Reform Excess ADIT Reversal	(21.3)		(47.9)	(73.4)
Other	(0.2)		(2.2)	(1.7)
Income Tax Expense (Benefit)	$ 43.1		$ (11.2)	$ (53.6)
Effective Income Tax Rate	12.90%		(4.90%)	(43.00%)
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 173.8		$ 183.6
Deferred Tax Liabilities	(1,262.7)		(1,200.3)
Property Related Temporary Differences	(1,060.2)		(1,039.6)
Amounts Due from Customers for Future Federal Income Taxes	110.0		114.4
Deferred State Income Taxes	(32.2)		(29.1)
Securitized Transition Assets	(84.4)		(90.2)
Regulatory Assets	(45.1)		(47.4)
Operating Lease Liability	15.8		18.0
All Other, Net	7.2		57.2
Net Deferred Tax Liabilities	(1,088.9)		(1,016.7)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	43.1		(11.2)	$ (53.6)
Operating Income (Loss)	$ (476.0)		(369.6)	(232.0)
AEP Texas Inc. [Member] | Minimum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2036
AEP Texas Inc. [Member] | Maximum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2040
AEP Transmission Co [Member]
Federal:
Current	$ 69.8		22.2	23.7
Deferred	54.1		65.4	71.7
Total Federal	123.9		87.6	95.4
Current	5.8		2.8	2.4
Deferred	14.4		16.3	19.6
Total State and Local	20.2		19.1	22.0
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	144.1		106.7	117.4
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	591.7		423.4	439.7
Income Tax Expense (Benefit)	144.1		106.7	117.4
Pretax Income	735.8		530.1	557.1
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 154.5		$ 111.3	$ 117.0
Federal Statutory Income Tax Rate	21.00%		21.00%	21.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
State and Local Income Taxes, Net	$ 19.8		$ 15.1	$ 17.4
AFUDC	(14.1)		(15.5)	(17.7)
Parent Company Loss Benefit	(18.3)		(7.0)	(4.2)
Other	2.2		2.8	4.9
Income Tax Expense (Benefit)	$ 144.1		$ 106.7	$ 117.4
Effective Income Tax Rate	19.60%		20.10%	21.10%
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 158.8		$ 166.5
Deferred Tax Liabilities	(1,121.7)		(1,073.4)
Property Related Temporary Differences	(997.0)		(937.8)
Amounts Due from Customers for Future Federal Income Taxes	118.2		118.9
Deferred State Income Taxes	(94.5)		(98.3)
Net Operating Loss Carryforward	8.1		13.2
All Other, Net	2.3		(2.9)
Net Deferred Tax Liabilities	(962.9)		(906.9)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	144.1		106.7	$ 117.4
Operating Income (Loss)	$ (809.3)		(581.5)	(567.2)
AEP Transmission Co [Member] | Minimum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2036
AEP Transmission Co [Member] | Maximum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2040
Appalachian Power Co [Member]
Federal:
Current	$ 5.0		21.4	36.7
Deferred	14.9		(27.1)	(126.1)
Total Federal	19.9		(5.7)	(89.4)
Current	2.2		9.3	12.0
Deferred	0.0		0.7	(0.6)
Total State and Local	2.2		10.0	11.4
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	22.1		4.3	(78.0)
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	348.9		369.7	306.3
Income Tax Expense (Benefit)	22.1		4.3	(78.0)
Pretax Income	371.0		374.0	228.3
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 77.9		$ 78.5	$ 47.9
Federal Statutory Income Tax Rate	21.00%		21.00%	21.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Depreciation	$ 11.7		$ 12.7	$ 10.8
State and Local Income Taxes, Net	2.1		7.9	9.0
Removal Costs	(7.3)		(5.7)	(6.4)
AFUDC	(4.6)		(4.5)	(5.2)
Parent Company Loss Benefit	0.0		(6.2)	(4.1)
Increase Decrease in Income Taxes Due to Tax Reserve Adjustments	4.5	[2]	0.0	0.0
Tax Reform Excess ADIT Reversal	(60.5)		(72.3)	(130.4)
Federal Return to Provision	(1.6)		(7.2)	(1.0)
Other	(0.1)		1.1	1.4
Income Tax Expense (Benefit)	$ 22.1		$ 4.3	$ (78.0)
Effective Income Tax Rate	6.00%		1.10%	(34.20%)
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 495.1		$ 500.6
Deferred Tax Liabilities	(2,299.8)		(2,250.5)
Property Related Temporary Differences	(1,476.5)		(1,412.0)
Amounts Due from Customers for Future Federal Income Taxes	182.1		198.3
Deferred State Income Taxes	(288.8)		(336.5)
Securitized Assets	(39.3)		(44.7)
Regulatory Assets	(177.0)		(114.8)
Operating Lease Liability	14.2		16.7
All Other, Net	(19.4)		(56.9)
Net Deferred Tax Liabilities	(1,804.7)		(1,749.9)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	22.1		4.3	$ (78.0)
Operating Income (Loss)	$ (549.4)		(556.6)	(397.3)
Appalachian Power Co [Member] | Minimum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2036
Appalachian Power Co [Member] | Maximum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2040
Indiana Michigan Power Co [Member]
Federal:
Current	$ 26.9		11.3	48.1
Deferred	(35.5)		(20.6)	(57.1)
Total Federal	(8.6)		(9.3)	(9.0)
Current	(0.6)		1.9	(2.4)
Deferred	(1.4)		(0.1)	0.8
Total State and Local	(2.0)		1.8	(1.6)
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	(10.6)		(7.5)	(10.6)
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	279.8		284.8	269.4
Income Tax Expense (Benefit)	(10.6)		(7.5)	(10.6)
Pretax Income	269.2		277.3	258.8
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 56.5		$ 58.2	$ 54.3
Federal Statutory Income Tax Rate	21.00%		21.00%	21.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Depreciation	$ 3.5		$ 1.6	$ 4.0
Investment Tax Credit Amortization	(6.4)		(4.5)	(3.6)
State and Local Income Taxes, Net	(1.3)		1.5	(1.2)
Removal Costs	(9.7)		(10.5)	(12.8)
AFUDC	(2.7)		(2.4)	(4.1)
Parent Company Loss Benefit	(2.8)		(6.4)	(3.3)
Tax Reform Excess ADIT Reversal	(46.3)		(46.8)	(42.5)
Other	(1.4)		1.8	(1.4)
Income Tax Expense (Benefit)	$ (10.6)		$ (7.5)	$ (10.6)
Effective Income Tax Rate	(3.90%)		(2.70%)	(4.10%)
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 1,072.2		$ 989.5
Deferred Tax Liabilities	(2,172.4)		(2,053.9)
Property Related Temporary Differences	(286.2)		(409.2)
Amounts Due from Customers for Future Federal Income Taxes	135.5		147.9
Deferred State Income Taxes	(222.0)		(211.1)
Regulatory Assets	(23.6)		(16.5)
Accrued Nuclear Decommissioning	(743.2)		(626.4)
Operating Lease Liability	13.5		46.6
All Other, Net	25.8		4.3
Net Deferred Tax Liabilities	(1,100.2)		(1,064.4)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	(10.6)		(7.5)	$ (10.6)
Operating Income (Loss)	$ (357.9)		(362.9)	(340.8)
Indiana Michigan Power Co [Member] | Minimum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2036
Indiana Michigan Power Co [Member] | Maximum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2040
Ohio Power Co [Member]
Federal:
Current	$ 6.8		(26.6)	(10.0)
Deferred	25.2		74.0	40.6
Total Federal	32.0		47.4	30.6
Current	(3.1)		(5.4)	1.1
Deferred	5.5		3.2	3.2
Total State and Local	2.4		(2.2)	4.3
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	34.4		45.2	34.9
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	253.6		271.4	297.1
Income Tax Expense (Benefit)	34.4		45.2	34.9
Pretax Income	288.0		316.6	332.0
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 60.5		$ 66.5	$ 69.7
Federal Statutory Income Tax Rate	21.00%		21.00%	21.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Depreciation	$ 2.2		$ 3.7	$ (1.4)
State and Local Income Taxes, Net	0.0		(1.7)	3.4
AFUDC	(2.3)		(2.6)	(3.8)
Increase Decrease in Income Taxes Due to Tax Reserve Adjustments	8.9	[2]	0.0	0.0
Tax Reform Excess ADIT Reversal	(32.6)		(27.2)	(27.3)
Federal Return to Provision	(1.2)		6.5	(3.7)
Other	(1.1)		0.0	(2.0)
Income Tax Expense (Benefit)	$ 34.4		$ 45.2	$ 34.9
Effective Income Tax Rate	11.90%		14.30%	10.50%
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 204.4		$ 210.8
Deferred Tax Liabilities	(1,205.3)		(1,165.9)
Property Related Temporary Differences	(1,042.0)		(1,016.0)
Amounts Due from Customers for Future Federal Income Taxes	117.7		121.1
Deferred State Income Taxes	(58.8)		(40.7)
Regulatory Assets	(39.8)		(53.7)
Operating Lease Liability	17.2		19.4
All Other, Net	4.8		14.8
Net Deferred Tax Liabilities	(1,000.9)		(955.1)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	34.4		45.2	$ 34.9
Operating Income (Loss)	$ (385.2)		(403.7)	(401.2)
Ohio Power Co [Member] | Minimum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2036
Ohio Power Co [Member] | Maximum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2040
Public Service Co Of Oklahoma [Member]
Federal:
Current	$ (109.6)		(11.4)	25.5
Deferred	105.6		8.3	(26.0)
Total Federal	(4.0)		(3.1)	(0.5)
Current	0.0		0.1	0.2
Deferred	8.1		8.2	7.8
Total State and Local	8.1		8.3	8.0
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	4.1		5.2	7.5
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	141.1		123.0	137.6
Income Tax Expense (Benefit)	4.1		5.2	7.5
Pretax Income	145.2		128.2	145.1
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 30.5		$ 26.9	$ 30.5
Federal Statutory Income Tax Rate	21.00%		21.00%	21.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Investment Tax Credit Amortization	$ (1.8)		$ (2.1)	$ (0.5)
Production Tax Credits	(6.0)		0.0	0.0
State and Local Income Taxes, Net	6.4		6.5	6.3
Parent Company Loss Benefit	0.0		(0.2)	(2.1)
Tax Reform Excess ADIT Reversal	(25.4)		(25.5)	(24.5)
Other	0.4		(0.4)	(2.2)
Income Tax Expense (Benefit)	$ 4.1		$ 5.2	$ 7.5
Effective Income Tax Rate	2.80%		4.10%	5.20%
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 170.0		$ 239.8
Deferred Tax Liabilities	(952.3)		(928.3)
Property Related Temporary Differences	(708.6)		(661.8)
Amounts Due from Customers for Future Federal Income Taxes	111.5		118.5
Deferred State Income Taxes	(83.2)		(107.7)
Regulatory Assets	(228.0)		(39.1)
Net Operating Loss Carryforward	111.4		12.9
All Other, Net	14.6		(11.3)
Net Deferred Tax Liabilities	(782.3)		(688.5)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	4.1		5.2	$ 7.5
Operating Income (Loss)	$ (192.9)		(175.9)	(199.3)
Public Service Co Of Oklahoma [Member] | Minimum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2036
Public Service Co Of Oklahoma [Member] | Maximum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2040
Southwestern Electric Power Co [Member]
Federal:
Current	$ (16.7)		(13.6)	6.9
Deferred	26.2		19.6	(10.0)
Total Federal	9.5		6.0	(3.1)
Current	0.4		(8.2)	0.8
Deferred	(10.5)		11.6	(2.4)
Total State and Local	(10.1)		3.4	(1.6)
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	(0.6)		9.4	(4.7)
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	242.1		183.7	162.2
Less: Equity Earnings – Dolet Hills	(3.4)		(2.9)	(3.0)
Income Tax Expense (Benefit)	(0.6)		9.4	(4.7)
Pretax Income	238.1		190.2	154.5
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 50.0		$ 39.9	$ 32.4
Federal Statutory Income Tax Rate	21.00%		21.00%	21.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Depreciation	$ 1.8		$ 1.9	$ 1.9
Depletion	(2.7)		(3.4)	(3.4)
Production Tax Credits	(7.2)		0.0	0.0
State and Local Income Taxes, Net	(8.0)		2.7	(1.3)
Parent Company Loss Benefit	0.0		(5.6)	(1.6)
Tax Reform Excess ADIT Reversal	(31.1)		(21.9)	(29.9)
Other	(3.4)		(4.2)	(2.8)
Income Tax Expense (Benefit)	$ (0.6)		$ 9.4	$ (4.7)
Effective Income Tax Rate	(0.30%)		4.90%	(3.00%)
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 336.4		$ 338.1
Deferred Tax Liabilities	(1,424.0)		(1,355.7)
Property Related Temporary Differences	(989.6)		(985.1)
Amounts Due from Customers for Future Federal Income Taxes	154.8		162.7
Deferred State Income Taxes	(234.9)		(214.7)
Regulatory Assets	(101.4)		(26.2)
Net Operating Loss Carryforward	67.4		33.4
All Other, Net	16.1		12.3
Net Deferred Tax Liabilities	(1,087.6)		(1,017.6)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	(0.6)		9.4	$ (4.7)
Operating Income (Loss)	$ (339.5)		(290.5)	(255.7)
Southwestern Electric Power Co [Member] | Minimum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2036
Southwestern Electric Power Co [Member] | Maximum [Member]
Income Taxes (Textuals) [Abstract]
Tax Credit Carryforward, Expiration Date	Dec. 31, 2040
Arkansas
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 161.8
Arkansas | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2022
Arkansas | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2031
Arkansas | Southwestern Electric Power Co [Member]
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 160.7
Arkansas | Southwestern Electric Power Co [Member] | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2022
Arkansas | Southwestern Electric Power Co [Member] | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2031
Kentucky
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 230.4
Kentucky | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2030
Kentucky | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
Louisiana
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 566.7
Louisiana | Southwestern Electric Power Co [Member]
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	554.7
Oklahoma
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 1,357.1
Oklahoma | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2034
Oklahoma | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
Oklahoma | AEP Transmission Co [Member]
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 107.8
Oklahoma | AEP Transmission Co [Member] | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2034
Oklahoma | AEP Transmission Co [Member] | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
Oklahoma | Public Service Co Of Oklahoma [Member]
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 1,229.8
Oklahoma | Public Service Co Of Oklahoma [Member] | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2034
Oklahoma | Public Service Co Of Oklahoma [Member] | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
Tennessee
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 53.0
Tennessee | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2030
Tennessee | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2036
Virginia
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 20.9
Virginia | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2030
Virginia | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
West Virginia
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 99.5
West Virginia | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2029
West Virginia | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
West Virginia | Appalachian Power Co [Member]
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 62.9
Ohio Municipal
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 1,027.9
Ohio Municipal | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2022
Ohio Municipal | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2026
Ohio Municipal | Ohio Power Co [Member]
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 76.0
Ohio Municipal | Ohio Power Co [Member] | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2022
Ohio Municipal | Ohio Power Co [Member] | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2026
Indiana
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 304.4
Colorado
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 82.8
Pennsylvania | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2030
Pennsylvania | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2041
Illinois
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 55.2
Federal
Tax Credit Carryforward
Tax Credit Carryforward, Amount	439.8
Federal | AEP Texas Inc. [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	0.3
Federal | AEP Transmission Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	0.1
Federal | Appalachian Power Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	1.3
Federal | Indiana Michigan Power Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	16.9
Federal | Ohio Power Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	0.4
Federal | Public Service Co Of Oklahoma [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	6.3
Federal | Southwestern Electric Power Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	7.9
State and Local Jurisdiction
Tax Credit Carryforward
Tax Credit Carryforward, Amount	38.8
Income Taxes (Textuals) [Abstract]
Valuation Allowance	25.0
State and Local Jurisdiction | AEP Texas Inc. [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	0.0
State and Local Jurisdiction | AEP Transmission Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	0.0
State and Local Jurisdiction | Appalachian Power Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	0.0
State and Local Jurisdiction | Indiana Michigan Power Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	0.0
State and Local Jurisdiction | Ohio Power Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	0.0
State and Local Jurisdiction | Public Service Co Of Oklahoma [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	38.8
State and Local Jurisdiction | Southwestern Electric Power Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	0.0
MICHIGAN
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 65.2
MICHIGAN | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2029
MICHIGAN | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2031
NEW JERSEY
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 36.5
NEW JERSEY | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2036
NEW JERSEY | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2041
NEW MEXICO
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 32.6
NEW MEXICO | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
NEW MEXICO | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2039
PENNSYLVANIA
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 82.7
COLORADO | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2041
COLORADO | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2041
ILLINOIS | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2031
ILLINOIS | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2041
INDIANA | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2039
INDIANA | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2041
Dolet Hills Lignite Co, LLC [Member]
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Less: Equity Earnings – Dolet Hills	$ (3.4)		(2.9)	(3.0)
Dolet Hills Lignite Co, LLC [Member] | Southwestern Electric Power Co [Member]
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Less: Equity Earnings – Dolet Hills	$ (3.4)		$ (2.9)	$ (3.0)

[1] Benefit at AEP is primarily due to an out of period adjustment related to Deferred Income Taxes and Income Tax Expense (Benefit). Management concluded the misstatement and subsequent correction was not material to prior or current period financial statements.

[2] Represents an out of period adjustment related to Deferred Income Taxes and Income Tax Expense (Benefit). Management concluded the misstatement and subsequent correction was not material to prior or current period financial statements.