Rate Matters Regulated Operations (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2021	Mar. 31, 2021	Mar. 31, 2020	Jun. 30, 2021	Dec. 31, 2020
Public Utilities, General Disclosures [Line Items]
Gross Investment Including CWIP		$ 23,687.3			$ 23,687.3	$ 23,133.9
Accumulated Depreciation		21,391.8			21,391.8	20,411.4
Net Investment		65,664.5			65,664.5	63,901.6
Materials and Supplies		676.2			676.2	680.6
Asset Retirement Obligation, Revision of Estimate	[1],[2],[3],[4]				66.4
Regulatory Assets, Noncurrent		5,048.2			5,048.2	3,527.0
Customers		794.8			794.8	613.6
Proceeds from Issuance of Debt	[5]				3,082.7
February 2021 Storm Event
Public Utilities, General Disclosures [Line Items]
Capitalized Storm Costs					64.6
Incremental Other Operation and Maintenance Expenses					6.4
Deferred Storm Costs as a Regulated Asset					137.6
Total Estimated February 2021 Storm Restoration Expenditures					208.6
February 2021 Severe Storm Fuel Costs
Public Utilities, General Disclosures [Line Items]
Customers		62.8			62.8
Total Estimated 2021 February Winter Storm Fuel Costs		1,185.2			1,185.2
February 2021 Severe Storm Fuel Costs | 364 Day Term Loan
Public Utilities, General Disclosures [Line Items]
Proceeds from Issuance of Debt					500.0
AEP Texas Inc. [Member]
Public Utilities, General Disclosures [Line Items]
Accumulated Depreciation		1,588.9			1,588.9	1,529.3
Net Investment		10,152.7			10,152.7	9,813.6
Materials and Supplies		69.5			69.5	70.0
Regulatory Assets, Noncurrent		292.0			292.0	266.8
Customers		141.7			141.7	112.8
AEP Texas Inc. [Member] | Senior Unsecured Notes [Member]
Public Utilities, General Disclosures [Line Items]
Proceeds from Issuance of Debt	[5]				450.0
AEP Transmission Co [Member]
Public Utilities, General Disclosures [Line Items]
Accumulated Depreciation		677.1			677.1	572.8
Net Investment		11,376.5			11,376.5	10,772.8
Materials and Supplies		9.0			9.0	8.5
Regulatory Assets, Noncurrent		14.8			14.8	15.1
Customers		29.7			29.7	22.9
Capital Contribution from Member		60.0	$ 124.0	$ 185.0
AEP Transmission Co [Member] | Additional Paid-in Capital [Member]
Public Utilities, General Disclosures [Line Items]
Capital Contribution from Member		60.0	124.0	$ 185.0
Appalachian Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Gross Investment Including CWIP		6,653.9			6,653.9	6,633.7
Accumulated Depreciation		4,888.8			4,888.8	4,716.2
Net Investment		11,526.5			11,526.5	11,394.1
Materials and Supplies		102.5			102.5	99.6
Asset Retirement Obligation, Revision of Estimate	[2],[3]				78.6
Regulatory Assets, Noncurrent		830.4			830.4	686.3
Customers		149.7			149.7	142.8
Appalachian Power Co [Member] | Senior Unsecured Notes [Member]
Public Utilities, General Disclosures [Line Items]
Proceeds from Issuance of Debt	[5]				500.0
Appalachian Power Co [Member] | February 2021 Storm Event | Virginia
Public Utilities, General Disclosures [Line Items]
Capitalized Storm Costs					8.0
Incremental Other Operation and Maintenance Expenses					2.2
Deferred Storm Costs as a Regulated Asset					6.6
Total Estimated February 2021 Storm Restoration Expenditures					16.8
Appalachian Power Co [Member] | February 2021 Storm Event | West Virginia
Public Utilities, General Disclosures [Line Items]
Capitalized Storm Costs					22.3
Incremental Other Operation and Maintenance Expenses					0.0
Deferred Storm Costs as a Regulated Asset					42.7
Total Estimated February 2021 Storm Restoration Expenditures					65.0
Indiana Michigan Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Gross Investment Including CWIP		5,324.7			5,324.7	5,264.7
Accumulated Depreciation		3,726.9			3,726.9	3,552.5
Net Investment		7,073.4			7,073.4	7,052.3
Materials and Supplies		171.0			171.0	175.8
Regulatory Assets, Noncurrent		433.1			433.1	404.8
Customers		50.7			50.7	44.0
Indiana Michigan Power Co [Member] | Senior Unsecured Notes [Member]
Public Utilities, General Disclosures [Line Items]
Proceeds from Issuance of Debt	[5]				450.0
Ohio Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Accumulated Depreciation		2,416.0			2,416.0	2,350.0
Net Investment		7,676.2			7,676.2	7,452.1
Materials and Supplies		68.8			68.8	66.9
Regulatory Assets, Noncurrent		399.7			399.7	385.8
Customers		86.1			86.1	50.0
Ohio Power Co [Member] | Senior Unsecured Notes [Member]
Public Utilities, General Disclosures [Line Items]
Proceeds from Issuance of Debt	[5]				450.0
Public Service Co Of Oklahoma [Member]
Public Utilities, General Disclosures [Line Items]
Gross Investment Including CWIP		1,609.3			1,609.3	1,480.7
Accumulated Depreciation		1,653.2			1,653.2	1,605.6
Net Investment		4,498.5			4,498.5	4,320.0
Materials and Supplies		52.8			52.8	54.0
Regulatory Assets, Noncurrent		1,054.0			1,054.0	375.0
Customers		38.6			38.6	30.8
Capital Contribution from Member		200.0	425.0
Public Service Co Of Oklahoma [Member] | Additional Paid-in Capital [Member]
Public Utilities, General Disclosures [Line Items]
Capital Contribution from Member		200.0	425.0
Public Service Co Of Oklahoma [Member] | Other Long Term Debt [Member]
Public Utilities, General Disclosures [Line Items]
Proceeds from Issuance of Debt	[5]				500.0
Public Service Co Of Oklahoma [Member] | February 2021 Severe Storm Fuel Costs
Public Utilities, General Disclosures [Line Items]
Customers		0.0			0.0
Total Estimated 2021 February Winter Storm Fuel Costs		669.4			$ 669.4
Interim WACC					0.75%
Public Service Co Of Oklahoma [Member] | Northeastern Plant, Unit 3 | Generating Units Probable of Abandonment [Member]
Public Utilities, General Disclosures [Line Items]
Net Investment		183.2			$ 183.2
Accelerated Depreciation Regulatory Asset		119.2			119.2
Cost of Removal Regulatory Liability	[6]	19.9			$ 19.9
Expected Retirement Date	[7]				2026
Depreciation	[8]				$ 14.9
Public Service Co Of Oklahoma [Member] | February 2021 Severe Storm Fuel Costs
Public Utilities, General Disclosures [Line Items]
Capital Contribution from Member		125.0	425.0
Public Service Co Of Oklahoma [Member] | February 2021 Severe Storm Fuel Costs | Other Long Term Debt [Member]
Public Utilities, General Disclosures [Line Items]
Proceeds from Issuance of Debt					100.0
Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Gross Investment Including CWIP		4,839.4			4,839.4	4,681.4
Accumulated Depreciation		3,375.4			3,375.4	3,158.5
Net Investment		7,168.5			7,168.5	7,088.2
Materials and Supplies		88.1			88.1	95.8
Regulatory Assets, Noncurrent		1,006.2			1,006.2	403.1
Net Over-Recovered Fuel Costs		17.0			17.0
Customers		102.2			102.2	27.1
Capital Contribution from Member		75.0	100.0
Southwestern Electric Power Co [Member] | Additional Paid-in Capital [Member]
Public Utilities, General Disclosures [Line Items]
Capital Contribution from Member		75.0	100.0
Southwestern Electric Power Co [Member] | Senior Unsecured Notes [Member]
Public Utilities, General Disclosures [Line Items]
Proceeds from Issuance of Debt	[5]				500.0
Southwestern Electric Power Co [Member] | 2020 Texas Fuel Reconciliation
Public Utilities, General Disclosures [Line Items]
Amount of Fuel Costs Under Review		1,700.0			1,700.0
Southwestern Electric Power Co [Member] | 2020 Texas Fuel Reconciliation | TEXAS
Public Utilities, General Disclosures [Line Items]
Amount of Fuel Costs Under Review		616.0			616.0
Recommended Disallowance from Staff or Intervenors					125.0
Reduction in Recoverable Fuel Costs					10.0
Southwestern Electric Power Co [Member] | February 2021 Storm Event
Public Utilities, General Disclosures [Line Items]
Capitalized Storm Costs					5.7
Incremental Other Operation and Maintenance Expenses					0.0
Deferred Storm Costs as a Regulated Asset					45.7
Total Estimated February 2021 Storm Restoration Expenditures					51.4
Southwestern Electric Power Co [Member] | February 2021 Severe Storm Fuel Costs
Public Utilities, General Disclosures [Line Items]
Customers		62.8			62.8
Total Estimated 2021 February Winter Storm Fuel Costs		515.8			515.8
Amount Billed to Wholesale Customers					$ 104.0
Southwestern Electric Power Co [Member] | February 2021 Severe Storm Fuel Costs | Arkansas
Public Utilities, General Disclosures [Line Items]
Requested Weighted Average Cost of Capital					6.05%
Intervenor Recommended WACC					1.65%
Southwestern Electric Power Co [Member] | Dolet Hills Power Station [Member] | Generating Units Probable of Abandonment [Member]
Public Utilities, General Disclosures [Line Items]
Net Investment		27.3			$ 27.3
Accelerated Depreciation Regulatory Asset		114.3			114.3
Cost of Removal Regulatory Liability		24.2			$ 24.2
Expected Retirement Date	[9]				2021
Depreciation	[8]				$ 7.8
Southwestern Electric Power Co [Member] | Dolet Hills Power Station and Related Fuel Operations
Public Utilities, General Disclosures [Line Items]
Percent of Fuel Supply Provided by DHLC					100.00%
Share of Net Investment in Dolet Hills Power Station		147.0			$ 147.0
Dolet Hills Lignite Company Unbilled Fixed Costs		119.0			119.0
Recovery of 2021 Dolet Hills Fuel Costs					20.0
Approved Deferral of Dolet Hills Fuel Costs		30.0
Southwestern Electric Power Co [Member] | Pirkey Power Plant and Related Fuel Operations
Public Utilities, General Disclosures [Line Items]
Share of Net Investment in Pirkey Power Plant		206.0			206.0
Pirkey Power Plant and Sabine Unbilled Fixed Costs		148.0			148.0
Southwestern Electric Power Co [Member] | Pirkey Generating Station (Unit No. 1) | Generating Units Probable of Abandonment [Member]
Public Utilities, General Disclosures [Line Items]
Net Investment		157.1			157.1
Accelerated Depreciation Regulatory Asset		49.4			49.4
Cost of Removal Regulatory Liability		38.9			$ 38.9
Expected Retirement Date	[10]				2023
Depreciation	[8]				$ 13.6
Southwestern Electric Power Co [Member] | Welsh Plant Unit 1 and 3 | Generating Units Probable of Abandonment [Member]
Public Utilities, General Disclosures [Line Items]
Net Investment		511.2			511.2
Accelerated Depreciation Regulatory Asset		24.9			24.9
Cost of Removal Regulatory Liability	[11]	57.8			$ 57.8
Expected Retirement Date	[12]				2028
Depreciation	[8]				$ 33.2
Southwestern Electric Power Co [Member] | February 2021 Severe Storm Fuel Costs
Public Utilities, General Disclosures [Line Items]
Capital Contribution from Member			$ 100.0
Southwestern Electric Power Co [Member] | February 2021 Severe Storm Fuel Costs | Senior Unsecured Notes [Member]
Public Utilities, General Disclosures [Line Items]
Proceeds from Issuance of Debt					500.0
Kentucky Power Co [Member] | Other Long Term Debt [Member]
Public Utilities, General Disclosures [Line Items]
Proceeds from Issuance of Debt	[5]				150.0
Kentucky Power Co [Member] | February 2021 Storm Event
Public Utilities, General Disclosures [Line Items]
Capitalized Storm Costs					28.6
Incremental Other Operation and Maintenance Expenses					4.2
Deferred Storm Costs as a Regulated Asset					42.6
Total Estimated February 2021 Storm Restoration Expenditures					75.4
Regulatory Assets Pending Final Regulatory Approval [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		1,846.0			1,846.0	442.2
Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		50.4			50.4	32.9
Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		101.5			101.5	43.8
Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		2.2			2.2	4.3
Regulatory Assets Pending Final Regulatory Approval [Member] | Ohio Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		8.6			8.6	8.4
Regulatory Assets Pending Final Regulatory Approval [Member] | Public Service Co Of Oklahoma [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		731.7			731.7	50.5
Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		852.6			852.6	247.3
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | February 2021 Severe Storm Fuel Costs
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	[13]	1,122.4			1,122.4
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Oklaunion Power Station Accelerated Depreciation [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		33.5			33.5	34.4
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Kentucky Deferred Purchase Power Expenses [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		44.4			44.4	41.3
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Plant Retirement Costs - Unrecovered Plant [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		35.2			35.2	35.2
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Dolet Hills Power Station Accelerated Depreciation [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		114.3			114.3	71.2
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		26.8			26.8	22.8
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | February 2021 Severe Storm Fuel Costs
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	[14]	1,122.4			1,122.4	0.0
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Pirkey Power Plant Accelerated Depreciation
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		49.4			49.4	12.2
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Welsh Unit 1 and 3 Accelerated Depreciation
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		24.9			24.9	3.6
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] | Adavanced Metering System
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		16.6			16.6	16.3
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | COVID-19 - Virginia
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		4.8			4.8	3.7
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		0.0			0.0	0.5
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Public Service Co Of Oklahoma [Member] | February 2021 Severe Storm Fuel Costs
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	[13]	669.4			669.4
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Public Service Co Of Oklahoma [Member] | Oklaunion Power Station Accelerated Depreciation [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		33.5			33.5	34.4
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Public Service Co Of Oklahoma [Member] | February 2021 Severe Storm Fuel Costs
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	[15]	669.4			669.4	0.0
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | February 2021 Severe Storm Fuel Costs
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	[13],[16]	453.0			453.0
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | February 2021 Severe Storm Fuel Costs | Arkansas
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		116.0			116.0
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | February 2021 Severe Storm Fuel Costs | Louisiana Jurisdiction [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		161.0			161.0
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | February 2021 Severe Storm Fuel Costs | Texas
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		176.0			176.0
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Dolet Hills Power Station Accelerated Depreciation [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		114.3			114.3	71.2
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Plant Retirement Costs - Unrecovered Plant, Louisiana [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		35.2			35.2	35.2
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		5.4			5.4	2.2
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | February 2021 Severe Storm Fuel Costs
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	[17]	453.0			453.0	0.0
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Pirkey Power Plant Accelerated Depreciation
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		49.4			49.4	12.2
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Welsh Unit 1 and 3 Accelerated Depreciation
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		24.9			24.9	3.6
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | COVID-19
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		17.4			17.4	24.9
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Plant Retirement Costs - Asset Retirement Obligation Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		25.9			25.9	25.9
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Storm Related Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		301.0			301.0	134.2
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		37.2			37.2	27.2
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Environmental Expense Deferral - Virginia
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		13.6			13.6	9.3
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] | COVID-19
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		6.5			6.5	10.5
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] | Storm Related Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		13.7			13.7	0.8
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		4.3			4.3	1.5
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] | Texas Retail Electric Provider Bad Debt Expense
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		4.1			4.1	0.0
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] | Vegetation Management Programs
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		5.2			5.2	3.8
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | Plant Retirement Costs - Asset Retirement Obligation Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		25.9			25.9	25.9
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | Storm Related Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		55.2			55.2	3.4
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | COVID-19 - West Virginia
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		1.9			1.9	1.5
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		0.1			0.1	0.0
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | Environmental Expense Deferral - Virginia
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		13.6			13.6	9.3
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member] | COVID-19
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		1.6			1.6	3.8
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		0.6			0.6	0.0
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Ohio Power Co [Member] | COVID-19
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		1.8			1.8	4.4
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Ohio Power Co [Member] | Storm Related Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		6.7			6.7	4.0
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Ohio Power Co [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		0.1			0.1	0.0
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Public Service Co Of Oklahoma [Member] | COVID-19
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		0.8			0.8	0.3
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Public Service Co Of Oklahoma [Member] | Storm Related Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		28.0			28.0	15.8
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Asset Retirement Obligation - Louisiana [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		9.7			9.7	9.1
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		16.4			16.4	14.5
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Storm Related Costs - Louisiana
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent		$ 144.3			$ 144.3	$ 99.3

[1] Includes ARO related to Sabine and DHLC.

[2] Includes ARO related to asbestos removal.

[3] Includes ARO related to ash disposal facilities.

[4] Includes ARO related to nuclear decommissioning costs for the Cook Plant of $1.83 billion and $1.80 billion as of June 30, 2021 and December 31, 2020, respectively.

[5] Amounts indicated on the statements of cash flows are net of issuance costs and premium or discount and will not tie to the issuance amounts.

[6] Includes Northeastern Plant, Unit 4, which was retired in 2016. Removal of Northeastern Plant, Unit 4, will be performed with Northeastern Plant, Unit 3, after retirement.

[7] Northeastern Plant, Unit 3 is currently being recovered through 2040. Accelerated recovery has been requested in the 2021 Oklahoma base rate case.

[8] Represents the amount of annual depreciation that has been collected from customers over the prior 12-month period

[9] Dolet Hills Power Station is currently being recovered through 2026 in the Louisiana jurisdiction and through 2046 in the Arkansas and Texas jurisdictions.

[10] Pirkey Power Plant is currently being recovered through 2025 in the Louisiana jurisdiction and through 2045 in the Arkansas and Texas jurisdictions.

[11] Includes Welsh Plant, Unit 2, which was retired in 2016. Removal of Welsh Plant, Unit 2, will be performed with Welsh Plant, Units 1 and 3, after retirement.

[12] Unit 1 is being recovered through 2027 in the Louisiana jurisdiction and through 2037 in the Arkansas and Texas jurisdictions. Unit 3 is being recovered through 2032 in the Louisiana jurisdiction and through 2042 in the Arkansas and Texas jurisdictions.

[13] These costs were deferred as regulatory assets as of June 30, 2021.

[14] PSO and SWEPCo have active fuel clauses that allow for the recovery of prudently incurred fuel and purchased power expenses. However, the recovery of these costs from customers may be extended over longer than usual time periods to mitigate the impact on customer bills. See “Impacts of Severe Winter Weather” section below for additional information.

[15] PSO has an active fuel clause that allows for the recovery of prudently incurred fuel and purchased power expenses. However, the recovery of these costs from customers may be extended over longer than usual time periods to mitigate the impact on customer bills. See “Impacts of Severe Winter Weather” section below for additional information.

[16] SWEPCo’s balance consists of $116 million, $161 million and $176 million related to the Arkansas, Louisiana and Texas jurisdictions, respectively.

[17] SWEPCo has an active fuel clause that allows for the recovery of prudently incurred fuel and purchased power expenses. However, the recovery of these costs from customers may be extended over longer than usual time periods to mitigate the impact on customer bills. See “Impacts of Severe Winter Weather” section below for additional information