Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Activities
Net Income (Loss)	$ 718.1	$ 578.8
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	792.4	696.3
Rockport Plant, Unit 2 Operating Lease Amortization	0.0	32.8
Deferred Income Taxes	(17.7)	44.3
Allowance for Equity Funds Used During Construction	(31.0)	(33.4)
Mark-to-Market of Risk Management Contracts	282.3	21.0
Amortization of Nuclear Fuel	22.9	22.7
Property Taxes	(82.0)	(74.8)
Deferred Fuel Over/Under-Recovery, Net	(148.8)	(1,225.1)
Change in Other Noncurrent Assets	26.5	(168.9)
Change in Other Noncurrent Liabilities	36.9	83.5
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	(24.3)	(12.9)
Fuel, Materials and Supplies	27.6	39.5
Accounts Payable	(1.0)	171.8
Accrued Taxes, Net	(51.8)	(80.8)
Other Current Assets	133.9	(26.3)
Other Current Liabilities	(61.8)	(185.7)
Net Cash Flows from (Used for) Operating Activities	1,622.2	(117.2)
Investing Activities
Construction Expenditures	(1,686.6)	(1,492.7)
Purchases of Investment Securities	(508.5)	(337.6)
Sales of Investment Securities	497.4	325.5
Acquisitions of Nuclear Fuel	(31.1)	(55.9)
Other Investing Activities	42.9	29.4
Net Cash Flows from (Used for) Investing Activities	(2,893.2)	(1,634.2)
Financing Activities
Issuance of Common Stock	809.5	184.6
Issuance of Long-term Debt	499.6	1,951.5
Issuance of Short-term Debt with Original Maturities greater than 90 Days	271.0	644.2
Change in Short-term Debt with Original Maturities less than 90 Days, Net	710.3	16.9
Retirement of Long-term Debt	(51.0)	(650.7)
Redemption of Short-term Debt with Original Maturities Greater than 90 Days	(215.0)	(92.0)
Principal Payments for Finance Leases Obligations	(14.7)	(15.0)
Dividends Paid on Common Stock	(398.8)	(372.0)
Other Financing Activities	(65.8)	(30.4)
Net Cash Flows from (Used for) Financing Activities	1,545.1	1,637.1
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash	274.1	(114.3)
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	451.4	438.3
Cash and Cash Equivalents at Beginning of Period	403.4
Cash, Cash Equivalents and Restricted Cash at End of Period	725.5	324.0
Cash and Cash Equivalents at End of Period	675.6
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	233.9	220.5
Net Cash Paid (Received) for Income Taxes	6.9	(0.2)
Noncash Acquisitions Under Finance Leases	7.2	9.0
Construction Expenditures Included in Current Liabilities as of March 31,	758.6	762.7
Acquisition of Nuclear Fuel Included in Current Liabilities as of March 31,	0.0	6.7
Forward Equity Purchase Contract Included in Current and Noncurrent Liabilities as of September 30,	16.7	19.1
Retained Earnings [Member]
Supplementary Information
Forward Equity Purchase Contract Included in Current and Noncurrent Liabilities as of September 30,	1.5	0.6
Dry Lake Solar Project
Investing Activities
Acquisitions of Assets	0.0	(102.9)
North Central Wind Energy Facilities
Investing Activities
Acquisitions of Assets	(1,207.3)	0.0
AEP Texas Inc. [Member]
Operating Activities
Net Income (Loss)	69.6	46.1
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	108.8	97.5
Deferred Income Taxes	7.0	1.7
Allowance for Equity Funds Used During Construction	(4.3)	(4.1)
Mark-to-Market of Risk Management Contracts	(0.2)	0.0
Property Taxes	(79.5)	(71.1)
Change in Other Noncurrent Assets	(17.0)	(14.8)
Change in Other Noncurrent Liabilities	5.8	14.7
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	(20.2)	(6.8)
Fuel, Materials and Supplies	(4.9)	0.3
Accounts Payable	9.6	1.4
Accrued Taxes, Net	37.9	34.1
Other Current Assets	0.8	0.3
Other Current Liabilities	16.5	(15.2)
Net Cash Flows from (Used for) Operating Activities	129.9	84.1
Investing Activities
Construction Expenditures	(356.6)	(295.1)
Change in Advances to Affiliates, Net	0.1	0.3
Other Investing Activities	13.7	17.0
Net Cash Flows from (Used for) Investing Activities	(342.8)	(277.8)
Financing Activities
Change in Advances from Affiliates, Net	235.3	216.9
Retirement of Long-term Debt	(11.4)	(11.2)
Principal Payments for Finance Leases Obligations	(1.7)	(1.7)
Other Financing Activities	0.2	0.3
Net Cash Flows from (Used for) Financing Activities	222.4	204.3
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash	9.5	10.6
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	30.5	28.8
Cash and Cash Equivalents at Beginning of Period	0.1
Cash, Cash Equivalents and Restricted Cash at End of Period	40.0	39.4
Cash and Cash Equivalents at End of Period	0.1
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	29.9	30.0
Noncash Acquisitions Under Finance Leases	0.6	0.8
Construction Expenditures Included in Current Liabilities as of March 31,	147.6	120.5
AEP Texas Inc. [Member] | Retained Earnings [Member]
Operating Activities
Net Income (Loss)	69.6	46.1
AEP Transmission Co [Member]
Operating Activities
Net Income (Loss)	155.4	151.7
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	83.1	70.6
Deferred Income Taxes	23.1	8.3
Allowance for Equity Funds Used During Construction	(15.6)	(16.7)
Property Taxes	31.3	30.0
Change in Other Noncurrent Assets	2.1	1.4
Change in Other Noncurrent Liabilities	11.8	0.6
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	(21.8)	(16.5)
Fuel, Materials and Supplies	(0.8)	(0.3)
Accounts Payable	3.6	(18.9)
Accrued Taxes, Net	(53.7)	(35.1)
Accrued Interest	20.4	24.3
Other Current Assets	0.5	0.9
Other Current Liabilities	(0.6)	1.4
Net Cash Flows from (Used for) Operating Activities	238.8	201.7
Investing Activities
Construction Expenditures	(417.1)	(400.5)
Change in Advances to Affiliates, Net	22.6	3.0
Other Investing Activities	(1.7)	(0.8)
Net Cash Flows from (Used for) Investing Activities	(396.2)	(398.3)
Financing Activities
Capital Contributions from Parent	0.0	124.0
Change in Advances from Affiliates, Net	197.4	72.6
Dividends Paid on Common Stock	(40.0)	0.0
Net Cash Flows from (Used for) Financing Activities	157.4	196.6
Net Increase (Decrease) in Cash and Cash Equivalents	0.0	0.0
Cash and Cash Equivalents at Beginning of Period	0.0	0.0
Cash and Cash Equivalents at End of Period	0.0	0.0
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	16.4	8.9
Construction Expenditures Included in Current Liabilities as of March 31,	214.6	244.5
AEP Transmission Co [Member] | Retained Earnings [Member]
Operating Activities
Net Income (Loss)	155.4	151.7
Financing Activities
Dividends Paid on Common Stock	(40.0)
Appalachian Power Co [Member]
Operating Activities
Net Income (Loss)	120.2	122.5
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	145.2	135.8
Deferred Income Taxes	4.1	(1.7)
Allowance for Equity Funds Used During Construction	(2.0)	(3.5)
Mark-to-Market of Risk Management Contracts	34.3	12.1
Deferred Fuel Over/Under-Recovery, Net	(100.3)	(6.4)
Change in Other Noncurrent Assets	1.4	(54.3)
Change in Other Noncurrent Liabilities	(20.4)	6.8
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	72.4	25.1
Fuel, Materials and Supplies	19.5	25.2
Increase (Decrease) in Margin Deposits Outstanding	61.4	(5.2)
Accounts Payable	33.6	46.0
Accrued Taxes, Net	26.1	8.2
Other Current Assets	2.3	1.6
Other Current Liabilities	18.3	3.1
Net Cash Flows from (Used for) Operating Activities	416.1	315.3
Investing Activities
Construction Expenditures	(233.9)	(187.5)
Change in Advances to Affiliates, Net	1.1	(239.7)
Other Investing Activities	9.7	6.6
Net Cash Flows from (Used for) Investing Activities	(223.1)	(420.6)
Financing Activities
Issuance of Long-term Debt	0.0	494.3
Change in Advances from Affiliates, Net	(163.8)	(18.6)
Retirement of Long-term Debt	(12.7)	(362.5)
Principal Payments for Finance Leases Obligations	(2.0)	(1.9)
Dividends Paid on Common Stock	(18.8)	(12.5)
Other Financing Activities	0.2	0.2
Net Cash Flows from (Used for) Financing Activities	(197.1)	99.0
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash	(4.1)	(6.3)
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	20.1	22.7
Cash and Cash Equivalents at Beginning of Period	2.5
Cash, Cash Equivalents and Restricted Cash at End of Period	16.0	16.4
Cash and Cash Equivalents at End of Period	6.0
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	21.0	28.9
Noncash Acquisitions Under Finance Leases	0.3	0.4
Construction Expenditures Included in Current Liabilities as of March 31,	94.9	96.1
Appalachian Power Co [Member] | Retained Earnings [Member]
Operating Activities
Net Income (Loss)	120.2	122.5
Indiana Michigan Power Co [Member]
Operating Activities
Net Income (Loss)	89.5	70.8
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	134.9	109.2
Rockport Plant, Unit 2 Operating Lease Amortization	0.0	16.6
Deferred Income Taxes	(11.5)	(12.1)
Amortization (Deferral) of Incremental Nuclear Refueling Outage Expenses, Net	(6.5)	4.9
Allowance for Equity Funds Used During Construction	(2.9)	(3.5)
Mark-to-Market of Risk Management Contracts	(2.8)	2.7
Amortization of Nuclear Fuel	22.9	22.7
Deferred Fuel Over/Under-Recovery, Net	6.1	(9.3)
Change in Other Noncurrent Assets	(5.2)	2.6
Change in Other Noncurrent Liabilities	2.4	24.1
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	25.9	14.4
Fuel, Materials and Supplies	6.3	8.8
Accounts Payable	3.8	(14.8)
Accrued Taxes, Net	22.3	21.6
Other Current Assets	15.3	5.2
Other Current Liabilities	(53.6)	(45.8)
Net Cash Flows from (Used for) Operating Activities	246.9	218.1
Investing Activities
Construction Expenditures	(129.9)	(120.2)
Purchases of Investment Securities	(507.7)	(336.9)
Sales of Investment Securities	493.5	320.0
Acquisitions of Nuclear Fuel	(31.1)	(55.9)
Other Investing Activities	0.3	3.2
Net Cash Flows from (Used for) Investing Activities	(174.9)	(189.8)
Financing Activities
Change in Advances from Affiliates, Net	(19.7)	21.6
Retirement of Long-term Debt	(23.8)	(24.1)
Principal Payments for Finance Leases Obligations	(1.6)	(1.5)
Dividends Paid on Common Stock	(25.0)	(25.0)
Other Financing Activities	0.1	0.2
Net Cash Flows from (Used for) Financing Activities	(70.0)	(28.8)
Net Increase (Decrease) in Cash and Cash Equivalents	2.0	(0.5)
Cash and Cash Equivalents at Beginning of Period	1.3	3.3
Cash and Cash Equivalents at End of Period	3.3	2.8
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	41.6	42.0
Noncash Acquisitions Under Finance Leases	0.3	2.4
Construction Expenditures Included in Current Liabilities as of March 31,	60.7	50.5
Acquisition of Nuclear Fuel Included in Current Liabilities as of March 31,	0.0	6.7
Indiana Michigan Power Co [Member] | Retained Earnings [Member]
Operating Activities
Net Income (Loss)	89.5	70.8
Ohio Power Co [Member]
Operating Activities
Net Income (Loss)	83.2	68.2
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	74.9	75.1
Deferred Income Taxes	9.5	4.5
Carrying Costs Income	(0.1)	(0.5)
Allowance for Equity Funds Used During Construction	(3.0)	(2.7)
Mark-to-Market of Risk Management Contracts	(24.0)	(6.3)
Property Taxes	87.0	78.3
Change in Other Noncurrent Assets	(1.2)	(20.9)
Change in Other Noncurrent Liabilities	11.0	3.8
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	(28.8)	(31.8)
Fuel, Materials and Supplies	(5.0)	(3.7)
Accounts Payable	4.0	(6.4)
Increase (Decrease) in Contract with Customer, Liability	24.1	(0.7)
Accrued Taxes, Net	(158.3)	(144.7)
Other Current Assets	13.5	(0.2)
Other Current Liabilities	20.3	(1.3)
Net Cash Flows from (Used for) Operating Activities	107.2	11.2
Investing Activities
Construction Expenditures	(188.7)	(178.2)
Change in Advances to Affiliates, Net	42.0	(0.5)
Other Investing Activities	4.2	2.6
Net Cash Flows from (Used for) Investing Activities	(142.5)	(176.1)
Financing Activities
Issuance of Long-term Debt	0.0	445.8
Change in Advances from Affiliates, Net	55.7	(259.2)
Principal Payments for Finance Leases Obligations	(1.2)	(1.2)
Dividends Paid on Common Stock	(15.0)	(21.9)
Other Financing Activities	0.2	0.1
Net Cash Flows from (Used for) Financing Activities	39.7	163.6
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash	4.4	(1.3)
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	3.0	7.4
Cash and Cash Equivalents at Beginning of Period	3.0
Cash, Cash Equivalents and Restricted Cash at End of Period	7.4	6.1
Cash and Cash Equivalents at End of Period	7.4
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	19.5	15.8
Noncash Acquisitions Under Finance Leases	0.6	0.4
Construction Expenditures Included in Current Liabilities as of March 31,	67.0	72.4
Ohio Power Co [Member] | Retained Earnings [Member]
Operating Activities
Net Income (Loss)	83.2	68.2
Public Service Co Of Oklahoma [Member]
Operating Activities
Net Income (Loss)	5.8	(2.7)
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	52.7	49.9
Deferred Income Taxes	(17.4)	(0.8)
Allowance for Equity Funds Used During Construction	(1.1)	(0.4)
Mark-to-Market of Risk Management Contracts	1.8	4.8
Property Taxes	(37.8)	(32.8)
Deferred Fuel Over/Under-Recovery, Net	(26.4)	(703.5)
Change in Other Noncurrent Assets	(3.9)	(7.3)
Change in Other Noncurrent Liabilities	6.2	1.5
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	11.5	(11.2)
Fuel, Materials and Supplies	0.0	4.5
Accounts Payable	(20.8)	15.2
Accrued Taxes, Net	45.2	22.4
Other Current Assets	1.9	(0.3)
Other Current Liabilities	(1.8)	(24.7)
Net Cash Flows from (Used for) Operating Activities	15.9	(685.4)
Investing Activities
Construction Expenditures	(104.1)	(79.9)
Acquisitions of Assets	549.3	0.0
Other Investing Activities	0.4	0.5
Net Cash Flows from (Used for) Investing Activities	(653.0)	(79.4)
Financing Activities
Capital Contributions from Parent	0.0	425.0
Issuance of Long-term Debt	500.0	500.0
Change in Advances from Affiliates, Net	139.5	90.3
Retirement of Long-term Debt	(0.1)	(250.1)
Principal Payments for Finance Leases Obligations	(0.8)	(0.9)
Other Financing Activities	0.1	0.3
Net Cash Flows from (Used for) Financing Activities	638.7	764.6
Net Increase (Decrease) in Cash and Cash Equivalents	1.6	(0.2)
Cash and Cash Equivalents at Beginning of Period	1.3	2.6
Cash and Cash Equivalents at End of Period	2.9	2.4
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	21.3	16.9
Noncash Acquisitions Under Finance Leases	0.3	1.0
Construction Expenditures Included in Current Liabilities as of March 31,	37.1	22.2
Public Service Co Of Oklahoma [Member] | Retained Earnings [Member]
Operating Activities
Net Income (Loss)	5.8	(2.7)
Southwestern Electric Power Co [Member]
Operating Activities
Net Income (Loss)	45.1	63.4
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	77.8	69.6
Deferred Income Taxes	(9.5)	8.6
Allowance for Equity Funds Used During Construction	(1.6)	(2.1)
Mark-to-Market of Risk Management Contracts	(7.0)	1.1
Property Taxes	(64.5)	(61.6)
Deferred Fuel Over/Under-Recovery, Net	9.2	(461.1)
Change in Regulatory Assets	(3.5)	(89.1)
Change in Other Noncurrent Assets	33.4	6.1
Change in Other Noncurrent Liabilities	16.7	16.6
Changes in Certain Components of Working Capital:
Accounts Receivable, Net	7.6	(105.8)
Fuel, Materials and Supplies	(0.6)	0.4
Accounts Payable	(35.1)	95.1
Accrued Taxes, Net	75.7	73.9
Other Current Assets	3.8	8.2
Other Current Liabilities	(56.7)	(51.0)
Net Cash Flows from (Used for) Operating Activities	90.8	(427.7)
Investing Activities
Construction Expenditures	(129.5)	(91.4)
Change in Advances to Affiliates, Net	153.8	0.0
Acquisitions of Assets	658.0	0.0
Other Investing Activities	1.9	0.1
Net Cash Flows from (Used for) Investing Activities	(631.8)	(91.3)
Financing Activities
Capital Contributions from Parent	350.0	100.0
Issuance of Long-term Debt	0.0	496.8
Change in Short-term Debt with Original Maturities less than 90 Days, Net	0.0	(30.0)
Change in Advances from Affiliates, Net	202.9	(37.7)
Retirement of Long-term Debt	(1.6)	(1.6)
Principal Payments for Finance Leases Obligations	(2.7)	(2.6)
Dividends Paid on Common Stock	(0.8)	(1.0)
Other Financing Activities	0.1	0.1
Net Cash Flows from (Used for) Financing Activities	547.9	524.0
Net Increase (Decrease) in Cash and Cash Equivalents	6.9	5.0
Cash and Cash Equivalents at Beginning of Period	51.2	13.2
Cash and Cash Equivalents at End of Period	58.1	18.2
Supplementary Information
Cash Paid for Interest, Net of Capitalized Amounts	37.7	39.7
Noncash Acquisitions Under Finance Leases	1.0	1.5
Construction Expenditures Included in Current Liabilities as of March 31,	47.8	40.2
Noncontrolling Interest [Member]
Supplementary Information
Noncontrolling Interest Assumed - Dry Lake Solar Project	$ 0.0	$ 18.9