Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2014
Federal:
Current	$ (138.2)	$ (7.4)	$ (31.7)
Deferred	146.9	(71.6)	122.0
Total Federal	8.7	(79.0)	90.3
Current	(16.7)	4.4	30.8
Deferred	48.5	61.7	(5.8)
Total State and Local	31.8	66.1	25.0
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	40.5	(12.9)	115.3
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	2,196.7	1,919.8	1,931.3
Less: Equity Earnings – Dolet Hills	(91.1)	(72.1)	(73.1)
Income Tax Expense (Benefit)	40.5	(12.9)	115.3
Pretax Income	2,234.3	1,903.9	2,043.9
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 469.2	$ 399.8	$ 429.2
Federal Statutory Income Tax Rate	21.00%	21.00%	21.00%	35.00%	35.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Depreciation	$ 26.5	$ 20.4	$ 24.6
Investment Tax Credit Amortization	(18.8)	(13.0)	(20.4)
Production Tax Credits	(83.1)	(59.6)	(10.3)
State and Local Income Taxes, Net	25.1	52.2	19.7
Removal Costs	(18.6)	(22.2)	(18.6)
AFUDC	(32.5)	(37.1)	(29.4)
Tax Reform Adjustments	0.0	0.0	(10.9)
Tax Reform Excess ADIT Reversal	(268.2)	(353.2)	(257.2)
CARES Act Provision	(48.0)	0.0	0.0
Other	(11.1)	(0.2)	(11.4)
Income Tax Expense (Benefit)	$ 40.5	$ (12.9)	$ 115.3
Effective Income Tax Rate	1.80%	(0.70%)	5.60%
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 3,259.7	$ 3,246.1
Deferred Tax Liabilities	(11,500.6)	(10,834.3)
Property Related Temporary Differences	(7,340.5)	(6,602.9)
Amounts Due from Customers for Future Federal Income Taxes	1,075.8	1,173.5
Deferred State Income Taxes	(1,317.6)	(1,198.0)
Securitized Assets	(140.0)	(178.7)
Regulatory Assets	(391.6)	(371.1)
Accrued Nuclear Decommissioning	(626.4)	(557.4)
Net Operating Loss Carryforward	112.9	77.6
Tax Credit Carryforward	323.6	247.2
Operating Lease Liability	183.7	182.6
Investment in Partnership	(362.0)	(446.6)
All Other, Net	241.2	85.6
Net Deferred Tax Liabilities	(8,240.9)	(7,588.2)
Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits
Balance at January 1,	24.1	14.6	$ 86.6
Increase - Tax Positions Taken During a Prior Period	0.6	8.8	0.1
Decrease - Tax Positions Taken During a Prior Period	(14.5)	(2.1)	0.0
Increase - Tax Positions Taken During the Current Year	3.0	2.8	0.0
Decrease - Tax Positions Taken During the Current Year	0.0	0.0	0.0
Decrease - Settlements with Taxing Authorities	0.0	0.0	(71.0)
Decrease - Lapse of the Applicable Statute of Limitations	0.0	0.0	(1.1)
Balance at December 31,	13.2	24.1	14.6	$ 86.6
Tax Contingency [Abstract]
Unrecognized Tax Benefits, if Recognized - Amount	$ 12.0	20.0	12.0
Income Taxes (Textuals) [Abstract]
Period with No Change in Unrecognized Tax Benefits	12 months
Income Tax Expense (Benefit)	$ 40.5	(12.9)	115.3
Proceeds from Income Tax Refunds	20.0
Income Taxes Receivable	95.0
Tax Cuts and Jobs Act, Change in Tax Rate, Deferred Tax Asset, Income Tax Expense	$ 48.0
Meals and Entertainment, Deductibility, Percentage	100.00%
Deferred Tax Liabilities, Property, Plant and Equipment, Percentage	100.00%
Effective Income Tax Rate Reconciliation, Deduction, Percent	10.00%
Tax Cuts and Jobs Act, Non Deductible Executive Compensation	$ 1.0
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	$ 5.2	(31.8)	37.0
Deferred	(15.4)	(24.7)	(17.9)
Total Federal	(10.2)	(56.5)	19.1
Current	(0.1)	2.9	1.8
Deferred	(0.9)	0.0	(0.1)
Total State and Local	(1.0)	2.9	1.7
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	(11.2)	(53.6)	20.8
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	241.0	178.3	211.3
Income Tax Expense (Benefit)	(11.2)	(53.6)	20.8
Pretax Income	229.8	124.7	232.1
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 48.3	$ 26.2	$ 48.7
Federal Statutory Income Tax Rate	21.00%	21.00%	21.00%	35.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Depreciation	$ 1.0	$ 1.0	$ 0.7
Investment Tax Credit Amortization	(1.1)	(1.2)	(2.3)
State and Local Income Taxes, Net	(0.8)	2.3	1.3
AFUDC	(4.1)	(3.2)	(4.2)
Parent Company Loss Benefit	(4.5)	(3.8)	(3.0)
Tax Reform Adjustments	0.0	0.0	(11.0)
Tax Reform Excess ADIT Reversal	(47.9)	(73.4)	(11.8)
Other	(2.1)	(1.5)	2.4
Income Tax Expense (Benefit)	$ (11.2)	$ (53.6)	$ 20.8
Effective Income Tax Rate	(4.90%)	(43.00%)	9.00%
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 183.6	$ 220.0
Deferred Tax Liabilities	(1,200.3)	(1,185.4)
Property Related Temporary Differences	(1,039.6)	(973.5)
Amounts Due from Customers for Future Federal Income Taxes	114.4	126.7
Deferred State Income Taxes	(29.1)	(27.5)
Securitized Transition Assets	(90.2)	(124.3)
Regulatory Assets	(47.4)	(51.2)
Operating Lease Liability	18.0	17.2
All Other, Net	57.2	67.2
Net Deferred Tax Liabilities	(1,016.7)	(965.4)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	$ (11.2)	(53.6)	$ 20.8
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	$ 22.2	23.7	(14.2)
Deferred	65.4	71.7	82.3
Total Federal	87.6	95.4	68.1
Current	2.8	2.4	(0.6)
Deferred	16.3	19.6	16.6
Total State and Local	19.1	22.0	16.0
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	106.7	117.4	84.1
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	423.4	439.7	315.9
Income Tax Expense (Benefit)	106.7	117.4	84.1
Pretax Income	530.1	557.1	400.0
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 111.3	$ 117.0	$ 84.0
Federal Statutory Income Tax Rate	21.00%	21.00%	21.00%	35.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
State and Local Income Taxes, Net	$ 15.1	$ 17.4	$ 12.6
AFUDC	(15.5)	(17.7)	(14.1)
Parent Company Loss Benefit	(7.0)	(4.2)	(0.6)
Other	2.8	4.9	2.2
Income Tax Expense (Benefit)	$ 106.7	$ 117.4	$ 84.1
Effective Income Tax Rate	20.10%	21.10%	21.00%
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 166.5	$ 162.9
Deferred Tax Liabilities	(1,073.4)	(980.7)
Property Related Temporary Differences	(937.8)	(847.1)
Amounts Due from Customers for Future Federal Income Taxes	118.9	119.9
Deferred State Income Taxes	(98.3)	(86.1)
Net Operating Loss Carryforward	13.2	12.3
All Other, Net	(2.9)	(16.8)
Net Deferred Tax Liabilities	(906.9)	(817.8)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	$ 106.7	117.4	$ 84.1
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	$ 21.4	36.7	(31.9)
Deferred	(27.1)	(126.1)	(24.5)
Total Federal	(5.7)	(89.4)	(56.4)
Current	9.3	12.0	3.7
Deferred	0.7	(0.6)	7.8
Total State and Local	10.0	11.4	11.5
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	4.3	(78.0)	(44.9)
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	369.7	306.3	367.8
Income Tax Expense (Benefit)	4.3	(78.0)	(44.9)
Pretax Income	374.0	228.3	322.9
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 78.5	$ 47.9	$ 67.8
Federal Statutory Income Tax Rate	21.00%	21.00%	21.00%	35.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Depreciation	$ 12.7	$ 10.8	$ 9.4
State and Local Income Taxes, Net	7.9	9.0	9.1
Removal Costs	(5.7)	(6.4)	(7.9)
AFUDC	(4.5)	(5.2)	(4.3)
Parent Company Loss Benefit	(6.2)	(4.1)	(3.6)
Tax Reform Excess ADIT Reversal	(72.3)	(130.4)	(108.5)
Federal Return to Provision	(7.2)	(1.0)	(6.6)
Other	1.1	1.4	(0.3)
Income Tax Expense (Benefit)	$ 4.3	$ (78.0)	$ (44.9)
Effective Income Tax Rate	1.10%	(34.20%)	(13.90%)
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 500.6	$ 486.2
Deferred Tax Liabilities	(2,250.5)	(2,167.0)
Property Related Temporary Differences	(1,412.0)	(1,420.0)
Amounts Due from Customers for Future Federal Income Taxes	198.3	222.8
Deferred State Income Taxes	(336.5)	(337.2)
Securitized Assets	(44.7)	(49.3)
Regulatory Assets	(114.8)	(71.0)
Operating Lease Liability	16.7	16.5
All Other, Net	(56.9)	(42.6)
Net Deferred Tax Liabilities	(1,749.9)	(1,680.8)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	4.3	(78.0)	$ (44.9)
Proceeds from Income Tax Refunds	$ 7.0
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	$ 11.3	48.1	60.9
Deferred	(20.6)	(57.1)	(48.8)
Total Federal	(9.3)	(9.0)	12.1
Current	1.9	(2.4)	15.8
Deferred	(0.1)	0.8	1.2
Total State and Local	1.8	(1.6)	17.0
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	(7.5)	(10.6)	29.1
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	284.8	269.4	261.3
Income Tax Expense (Benefit)	(7.5)	(10.6)	29.1
Pretax Income	277.3	258.8	290.4
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 58.2	$ 54.3	$ 61.0
Federal Statutory Income Tax Rate	21.00%	21.00%	21.00%	35.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Depreciation	$ 1.6	$ 4.0	$ 1.5
Investment Tax Credit Amortization	(4.5)	(3.6)	(4.7)
State and Local Income Taxes, Net	1.5	(1.2)	13.4
Removal Costs	(10.5)	(12.8)	(8.0)
AFUDC	(2.4)	(4.1)	(2.5)
Parent Company Loss Benefit	(6.4)	(3.3)	(2.3)
Tax Reform Excess ADIT Reversal	(46.8)	(42.5)	(25.8)
Federal Return to Provision	1.9	(0.3)	(4.6)
Other	(0.1)	(1.1)	1.1
Income Tax Expense (Benefit)	$ (7.5)	$ (10.6)	$ 29.1
Effective Income Tax Rate	(2.70%)	(4.10%)	10.00%
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 989.5	$ 970.5
Deferred Tax Liabilities	(2,053.9)	(1,950.2)
Property Related Temporary Differences	(409.2)	(430.7)
Amounts Due from Customers for Future Federal Income Taxes	147.9	169.6
Deferred State Income Taxes	(211.1)	(194.4)
Regulatory Assets	(16.5)	(26.9)
Accrued Nuclear Decommissioning	(626.4)	(557.4)
Operating Lease Liability	46.6	61.9
All Other, Net	4.3	(1.8)
Net Deferred Tax Liabilities	(1,064.4)	(979.7)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	$ (7.5)	(10.6)	$ 29.1
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	$ (26.6)	(10.0)	55.6
Deferred	74.0	40.6	(36.9)
Total Federal	47.4	30.6	18.7
Current	(5.4)	1.1	4.6
Deferred	3.2	3.2	0.7
Total State and Local	(2.2)	4.3	5.3
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	45.2	34.9	24.0
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	271.4	297.1	325.5
Income Tax Expense (Benefit)	45.2	34.9	24.0
Pretax Income	316.6	332.0	349.5
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 66.5	$ 69.7	$ 73.4
Federal Statutory Income Tax Rate	21.00%	21.00%	21.00%	35.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Depreciation	$ 3.7	$ (1.4)	$ 2.4
State and Local Income Taxes, Net	(1.7)	3.4	4.2
AFUDC	(2.6)	(3.8)	(2.1)
Parent Company Loss Benefit	0.0	(1.8)	(6.0)
Tax Reform Excess ADIT Reversal	(27.2)	(27.3)	(51.0)
Federal Return to Provision	6.5	(3.7)	0.2
Other	0.0	(0.2)	2.9
Income Tax Expense (Benefit)	$ 45.2	$ 34.9	$ 24.0
Effective Income Tax Rate	14.30%	10.50%	6.90%
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 210.8	$ 202.3
Deferred Tax Liabilities	(1,165.9)	(1,051.6)
Property Related Temporary Differences	(1,016.0)	(890.8)
Amounts Due from Customers for Future Federal Income Taxes	121.1	130.2
Deferred State Income Taxes	(40.7)	(35.5)
Regulatory Assets	(53.7)	(48.0)
Operating Lease Liability	19.4	18.3
All Other, Net	14.8	(23.5)
Net Deferred Tax Liabilities	(955.1)	(849.3)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	45.2	34.9	$ 24.0
Proceeds from Income Tax Refunds	$ 9.0
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	$ (11.4)	25.5	35.6
Deferred	8.3	(26.0)	(36.7)
Total Federal	(3.1)	(0.5)	(1.1)
Current	0.1	0.2	(0.2)
Deferred	8.2	7.8	6.3
Total State and Local	8.3	8.0	6.1
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	5.2	7.5	5.0
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	123.0	137.6	83.2
Income Tax Expense (Benefit)	5.2	7.5	5.0
Pretax Income	128.2	145.1	88.2
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 26.9	$ 30.5	$ 18.5
Federal Statutory Income Tax Rate	21.00%	21.00%	21.00%	35.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Depreciation	$ 1.1	$ 0.6	$ 0.7
Investment Tax Credit Amortization	(2.1)	(0.5)	(1.7)
State and Local Income Taxes, Net	6.5	6.3	4.8
Parent Company Loss Benefit	(0.2)	(2.1)	(1.4)
Tax Reform Excess ADIT Reversal	(25.5)	(24.5)	(15.5)
Other	(1.5)	(2.8)	(0.4)
Income Tax Expense (Benefit)	$ 5.2	$ 7.5	$ 5.0
Effective Income Tax Rate	4.10%	5.20%	5.70%
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 239.8	$ 257.4
Deferred Tax Liabilities	(928.3)	(885.7)
Property Related Temporary Differences	(661.8)	(627.6)
Amounts Due from Customers for Future Federal Income Taxes	118.5	127.2
Deferred State Income Taxes	(107.7)	(100.4)
Regulatory Assets	(39.1)	(44.6)
Net Operating Loss Carryforward	12.9	10.2
All Other, Net	(11.3)	6.9
Net Deferred Tax Liabilities	(688.5)	(628.3)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	$ 5.2	7.5	$ 5.0
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	$ (13.6)	6.9	18.3
Deferred	19.6	(10.0)	(1.9)
Total Federal	6.0	(3.1)	16.4
Current	(8.2)	0.8	2.3
Deferred	11.6	(2.4)	1.7
Total State and Local	3.4	(1.6)	4.0
Income Tax Expense (Benefit):
Income Tax Expense (Benefit)	9.4	(4.7)	20.4
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Net Income	183.7	162.2	152.2
Less: Equity Earnings – Dolet Hills	(2.9)	(3.0)	(2.7)
Income Tax Expense (Benefit)	9.4	(4.7)	20.4
Pretax Income	190.2	154.5	169.9
Income Taxes on Pretax Income at Statutory Rate (21%)	$ 39.9	$ 32.4	$ 35.7
Federal Statutory Income Tax Rate	21.00%	21.00%	21.00%	35.00%
Reconciliation of Federal Statutory Rate and Amount of Taxes Reported
Depreciation	$ 1.9	$ 1.9	$ 1.9
Depletion	(3.4)	(3.4)	(3.4)
State and Local Income Taxes, Net	2.7	(1.3)	3.2
AFUDC	(1.5)	(1.4)	(1.3)
Parent Company Loss Benefit	(5.6)	(1.6)	(0.6)
Tax Reform Excess ADIT Reversal	(21.9)	(29.9)	(16.0)
Other	(2.7)	(1.4)	0.9
Income Tax Expense (Benefit)	$ 9.4	$ (4.7)	$ 20.4
Effective Income Tax Rate	4.90%	(3.00%)	12.00%
Net Deferred Tax Liability and Significant Temporary Differences
Deferred Tax Assets	$ 338.1	$ 359.6
Deferred Tax Liabilities	(1,355.7)	(1,300.5)
Property Related Temporary Differences	(985.1)	(947.6)
Amounts Due from Customers for Future Federal Income Taxes	162.7	169.8
Deferred State Income Taxes	(214.7)	(200.3)
Regulatory Assets	(26.2)	(30.2)
Net Operating Loss Carryforward	33.4	38.2
All Other, Net	12.3	29.2
Net Deferred Tax Liabilities	(1,017.6)	(940.9)
Income Taxes (Textuals) [Abstract]
Income Tax Expense (Benefit)	$ 9.4	(4.7)	$ 20.4
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	$ 87.2
Arkansas | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2021
Arkansas | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2028
Arkansas | Southwestern Electric Power Co [Member]
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 86.4
Arkansas | Southwestern Electric Power Co [Member] | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2021
Arkansas | Southwestern Electric Power Co [Member] | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2024
Kentucky
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 163.7
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	$ 466.8
Louisiana | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2025
Louisiana | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2040
Louisiana | Southwestern Electric Power Co [Member]
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 454.3
Louisiana | Southwestern Electric Power Co [Member] | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2032
Louisiana | Southwestern Electric Power Co [Member] | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
Oklahoma
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 569.4
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	$ 195.4
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	$ 354.5
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	$ 31.1
Tennessee | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2028
Tennessee | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2035
Virginia
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 29.4
Virginia | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2025
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	$ 21.9
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 | Indiana Michigan Power Co [Member]
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 2.5
West Virginia | Indiana Michigan Power Co [Member] | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2032
West Virginia | Indiana Michigan Power Co [Member] | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
Ohio Municipal
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 649.8
Ohio Municipal | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2021
Ohio Municipal | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2025
Ohio Municipal | AEP Transmission Co [Member]
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 18.4
Ohio Municipal | AEP Transmission Co [Member] | Minimum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2023
Ohio Municipal | AEP Transmission Co [Member] | Maximum [Member]
Net Income Tax Operating Loss Carryforwards
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2023
Indiana
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 145.7
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, 2039
Colorado
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 95.7
Pennsylvania
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 56.5
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, 2040
New Jersey
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 60.2
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, 2040
Illinois
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 15.6
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, 2031
Michigan
Net Income Tax Operating Loss Carryforwards
Net Income Tax Operating Loss Carryforward	$ 14.9
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, 2029
Federal
Tax Credit Carryforward
Tax Credit Carryforward, Amount	$ 323.6
Federal | AEP Texas Inc. [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	1.2
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	1.6
Federal | Indiana Michigan Power Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	9.7
Federal | Ohio Power Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	0.5
Federal | Public Service Co Of Oklahoma [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	0.5
Federal | Southwestern Electric Power Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	1.3
State and Local Jurisdiction
Tax Credit Carryforward
Tax Credit Carryforward, Amount	38.4
Income Taxes (Textuals) [Abstract]
Valuation Allowance	9.0
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	38.4
State and Local Jurisdiction | Southwestern Electric Power Co [Member]
Tax Credit Carryforward
Tax Credit Carryforward, Amount	0.0
Dolet Hills Lignite Co, LLC [Member]
Reconciliation of Federal Income Taxes and Amount of Income Tax Reported
Less: Equity Earnings – Dolet Hills	(2.9)	(3.0)	(2.7)
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	$ (2.9)	$ (3.0)	$ (2.7)