Fair Value Assets and Liabilities (Details) - USD ($)		3 Months Ended			9 Months Ended
		Sep. 30, 2023		Sep. 30, 2022	Sep. 30, 2023		Sep. 30, 2022	Dec. 31, 2022
Other [Member]
Risk Management Assets		$ (637,600,000)			$ (637,600,000)			$ (1,264,300,000)
Risk Management Liabilities		(545,100,000)			(545,100,000)			(784,700,000)
Assets, Fair Value Disclosure
Other Short-term Investments		13,400,000			13,400,000			9,000,000.0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		10,500,000			10,500,000			9,900,000
Total Assets		(613,700,000)			(613,700,000)			(1,245,400,000)
Risk Management Assets
Risk Management Assets		(637,600,000)			(637,600,000)			(1,264,300,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(545,100,000)			(545,100,000)			(784,700,000)
Risk Management Assets		552,900,000			552,900,000			632,900,000
Risk Management Liabilities		429,900,000			429,900,000			490,400,000
Other Short-term Investments		264,800,000			264,800,000			234,700,000
Spent Nuclear Fuel and Decommissioning Trusts		3,539,700,000			3,539,700,000			3,341,200,000
Total Assets		4,357,400,000			4,357,400,000			4,208,800,000
Risk Management Assets		552,900,000			552,900,000			632,900,000
Risk Management Liabilities		429,900,000			429,900,000			490,400,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		126,100,000		$ 283,900,000	160,400,000		$ 103,100,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	39,700,000		64,300,000	(41,300,000)		69,300,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	72,700,000		(12,600,000)	67,700,000		(44,600,000)
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	4,900,000		13,100,000	(10,500,000)		29,400,000
Settlements		(87,100,000)		(138,300,000)	(85,900,000)		(153,800,000)
Transfers into Level 3	[4],[5]			(500,000)	(6,100,000)		1,700,000
Transfers out of Level 3	[5]	6,600,000		3,500,000	3,800,000		13,200,000
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	19,900,000		72,500,000	94,700,000		267,600,000
Ending Balance		182,800,000		285,900,000	182,800,000		285,900,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		39,489,100,000			39,489,100,000			36,801,000,000
Level 1 [Member]
Risk Management Assets		11,400,000			11,400,000			15,000,000.0
Risk Management Liabilities		24,800,000			24,800,000			21,800,000
Assets, Fair Value Disclosure
Other Short-term Investments		251,400,000			251,400,000			225,700,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,184,500,000			2,184,500,000			2,142,600,000
Total Assets		2,447,300,000			2,447,300,000			2,383,300,000
Risk Management Assets
Risk Management Assets		11,400,000			11,400,000			15,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		24,800,000			24,800,000			21,800,000
Level 2 [Member]
Risk Management Assets		840,600,000			840,600,000			1,541,100,000
Risk Management Liabilities		794,500,000			794,500,000			1,072,600,000
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,344,700,000			1,344,700,000			1,188,700,000
Total Assets		2,185,300,000			2,185,300,000			2,729,800,000
Risk Management Assets
Risk Management Assets		840,600,000			840,600,000			1,541,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		794,500,000			794,500,000			1,072,600,000
Level 3 [Member]
Risk Management Assets		338,500,000			338,500,000			341,100,000
Risk Management Liabilities		155,700,000			155,700,000			180,700,000
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Total Assets		338,500,000			338,500,000			341,100,000
Risk Management Assets
Risk Management Assets		338,500,000			338,500,000			341,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		155,700,000			155,700,000			180,700,000
2023 [Member] | Level 1 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(4,000,000)			(4,000,000)			(7,000,000)
2023 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities								182,000,000
2023 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		37,000,000			37,000,000			128,000,000
2024 - 2026 [Member] | Level 1 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(9,000,000)			(9,000,000)
2024 - 2026 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		64,000,000			64,000,000			134,000,000
2024 - 2026 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		118,000,000			118,000,000			6,000,000
2027 - 2028 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		10,000,000			10,000,000			10,000,000
2027 - 2028 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		18,000,000			18,000,000			6,000,000
2029 - 2033 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		1,000,000			1,000,000			1,000,000
2029 - 2033 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(9,000,000)			(9,000,000)			(5,000,000)
Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[7]	(627,400,000)	[8]		(627,400,000)	[8]		(1,211,500,000)	[9]
Risk Management Liabilities	[7]	(534,900,000)	[8]		(534,900,000)	[8]		(731,900,000)	[9]
Risk Management Assets
Risk Management Assets	[7]	(627,400,000)	[8]		(627,400,000)	[8]		(1,211,500,000)	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	(534,900,000)	[8]		(534,900,000)	[8]		(731,900,000)	[9]
Risk Management Commodity Contracts [Member]
Risk Management Assets	[7]	424,500,000	[8]		424,500,000	[8]		315,400,000	[9]
Risk Management Liabilities	[7]	291,200,000	[8]		291,200,000	[8]		339,800,000	[9]
Risk Management Assets
Risk Management Assets	[7]	424,500,000	[8]		424,500,000	[8]		315,400,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	291,200,000	[8]		291,200,000	[8]		339,800,000	[9]
Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[7]	11,400,000	[8]		11,400,000	[8]		15,000,000.0	[9]
Risk Management Liabilities	[7]	24,800,000	[8]		24,800,000	[8]		21,800,000	[9]
Risk Management Assets
Risk Management Assets	[7]	11,400,000	[8]		11,400,000	[8]		15,000,000.0	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	24,800,000	[8]		24,800,000	[8]		21,800,000	[9]
Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[7]	721,300,000	[8]		721,300,000	[8]		1,197,500,000	[9]
Risk Management Liabilities	[7]	646,300,000	[8]		646,300,000	[8]		870,900,000	[9]
Risk Management Assets
Risk Management Assets	[7]	721,300,000	[8]		721,300,000	[8]		1,197,500,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	646,300,000	[8]		646,300,000	[8]		870,900,000	[9]
Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[7]	319,200,000	[8]		319,200,000	[8]		314,400,000	[9]
Risk Management Liabilities	[7]	155,000,000.0	[8]		155,000,000.0	[8]		179,000,000.0	[9]
Risk Management Assets
Risk Management Assets	[7]	319,200,000	[8]		319,200,000	[8]		314,400,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	155,000,000.0	[8]		155,000,000.0	[8]		179,000,000.0	[9]
Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets		224,300,000			224,300,000			204,000,000.0
Risk Management Liabilities		147,700,000			147,700,000			167,400,000
Risk Management Assets
Risk Management Assets		224,300,000			224,300,000			204,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		147,700,000			147,700,000			167,400,000
Energy Contracts [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	45.43			45.43			49.14
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	45.43			45.43			49.14
Energy Contracts [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	5.98			5.98			2.91
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	5.98			5.98			2.91
Energy Contracts [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	137.52			137.52			187.34
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	137.52			137.52			187.34
Natural Gas Contracts [Member] | Level 3 [Member]
Risk Management Assets		0			0
Risk Management Liabilities		200,000			200,000
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		200,000			200,000
Natural Gas Contracts [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[11],[12]	3.55			3.55
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[11],[12]	3.55			3.55
Natural Gas Contracts [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[12]	3.55			3.55
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]	3.55			3.55
Natural Gas Contracts [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[12]	3.55			3.55
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]	3.55			3.55
FTRs [Member] | Level 3 [Member]
Risk Management Assets		114,200,000			114,200,000			137,100,000
Risk Management Liabilities		7,800,000			7,800,000			13,300,000
Risk Management Assets
Risk Management Assets		114,200,000			114,200,000			137,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		7,800,000			7,800,000			13,300,000
FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.29			0.29			1.18
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.29			0.29			1.18
FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(17.92)			(17.92)			(36.45)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(17.92)			(17.92)			(36.45)
FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	17.07			17.07			20.72
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	17.07			17.07			20.72
Commodity Hedges [Member] | Other [Member]
Risk Management Assets	[7]	(10,200,000)			(10,200,000)			(52,800,000)
Risk Management Liabilities	[7]	(10,200,000)			(10,200,000)			(52,800,000)
Risk Management Assets
Risk Management Assets	[7]	(10,200,000)			(10,200,000)			(52,800,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	(10,200,000)			(10,200,000)			(52,800,000)
Commodity Hedges [Member]
Risk Management Assets	[7]	128,400,000			128,400,000			306,500,000
Risk Management Liabilities	[7]	600,000			600,000			23,200,000
Risk Management Assets
Risk Management Assets	[7]	128,400,000			128,400,000			306,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	600,000			600,000			23,200,000
Commodity Hedges [Member] | Level 1 [Member]
Risk Management Assets	[7]	0			0			0
Risk Management Liabilities	[7]	0			0			0
Risk Management Assets
Risk Management Assets	[7]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	0			0			0
Commodity Hedges [Member] | Level 2 [Member]
Risk Management Assets	[7]	119,300,000			119,300,000			332,600,000
Risk Management Liabilities	[7]	10,100,000			10,100,000			74,300,000
Risk Management Assets
Risk Management Assets	[7]	119,300,000			119,300,000			332,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	10,100,000			10,100,000			74,300,000
Commodity Hedges [Member] | Level 3 [Member]
Risk Management Assets	[7]	19,300,000			19,300,000			26,700,000
Risk Management Liabilities	[7]	700,000			700,000			1,700,000
Risk Management Assets
Risk Management Assets	[7]	19,300,000			19,300,000			26,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	700,000			700,000			1,700,000
Interest Rate [Member] | Other [Member]
Risk Management Assets								0
Risk Management Assets
Risk Management Assets								0
Interest Rate [Member]
Risk Management Assets								11,000,000.0
Risk Management Assets
Risk Management Assets								11,000,000.0
Interest Rate [Member] | Level 1 [Member]
Risk Management Assets								0
Risk Management Assets
Risk Management Assets								0
Interest Rate [Member] | Level 2 [Member]
Risk Management Assets								11,000,000.0
Risk Management Assets
Risk Management Assets								11,000,000.0
Interest Rate [Member] | Level 3 [Member]
Risk Management Assets								0
Risk Management Assets
Risk Management Assets								0
Fair Value Hedges [Member] | Other [Member]
Risk Management Liabilities		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			0
Fair Value Hedges [Member]
Risk Management Liabilities		138,100,000			138,100,000			127,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		138,100,000			138,100,000			127,400,000
Fair Value Hedges [Member] | Level 1 [Member]
Risk Management Liabilities		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			0
Fair Value Hedges [Member] | Level 2 [Member]
Risk Management Liabilities		138,100,000			138,100,000			127,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		138,100,000			138,100,000			127,400,000
Fair Value Hedges [Member] | Level 3 [Member]
Risk Management Liabilities		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			0
AEP Texas Inc. [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		0			0
AEP Texas Inc. [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		46,900,000			46,900,000			32,700,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		47,300,000			47,300,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		5,926,700,000			5,926,700,000			5,657,800,000
AEP Texas Inc. [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		46,900,000			46,900,000			32,700,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		46,900,000			46,900,000
AEP Texas Inc. [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		400,000			400,000
AEP Texas Inc. [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		0			0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[13]	0			0
Risk Management Assets
Risk Management Assets	[13]	0			0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[13]	400,000			400,000
Risk Management Assets
Risk Management Assets	[13]	400,000			400,000
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[13]	0			0
Risk Management Assets
Risk Management Assets	[13]	0			0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[13]	400,000			400,000
Risk Management Assets
Risk Management Assets	[13]	400,000			400,000
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[13]	0			0
Risk Management Assets
Risk Management Assets	[13]	0			0
AEP Transmission Co [Member]
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		5,473,700,000			5,473,700,000			4,782,800,000
Appalachian Power Co [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		(2,400,000)			(2,400,000)			(1,000,000.0)
Appalachian Power Co [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		6,900,000			6,900,000			14,400,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		53,500,000			53,500,000			83,500,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		39,400,000		79,600,000	69,100,000		41,700,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	10,000,000.0		20,100,000	(47,000,000.0)		3,000,000.0
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0	0		0
Settlements		(16,500,000)		(34,600,000)	(22,100,000)		(44,700,000)
Transfers into Level 3	[4],[5]			0	0		0
Transfers out of Level 3	[5]	100,000		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	12,100,000		41,500,000	45,100,000		106,600,000
Ending Balance		45,100,000		106,600,000	45,100,000		106,600,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		5,587,300,000			5,587,300,000			5,410,500,000
Appalachian Power Co [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		6,900,000			6,900,000			14,400,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		6,900,000			6,900,000			14,400,000
Appalachian Power Co [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		3,800,000			3,800,000			700,000
Appalachian Power Co [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		45,200,000			45,200,000			69,400,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[7],[13]	(2,400,000)			(2,400,000)			(1,000,000.0)
Risk Management Liabilities	[7],[13]	(2,400,000)			(2,400,000)			(1,400,000)
Risk Management Assets
Risk Management Assets	[7],[13]	(2,400,000)			(2,400,000)			(1,000,000.0)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	(2,400,000)			(2,400,000)			(1,400,000)
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[7],[13]	46,600,000			46,600,000			69,100,000
Risk Management Liabilities	[7],[13]	2,700,000			2,700,000			3,500,000
Risk Management Assets
Risk Management Assets	[7],[13]	46,600,000			46,600,000			69,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	2,700,000			2,700,000			3,500,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[7],[13]	0			0			0
Risk Management Liabilities	[7],[13]	0			0			0
Risk Management Assets
Risk Management Assets	[7],[13]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	0			0			0
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[7],[13]	3,800,000			3,800,000			700,000
Risk Management Liabilities	[7],[13]	5,000,000.0			5,000,000.0			4,600,000
Risk Management Assets
Risk Management Assets	[7],[13]	3,800,000			3,800,000			700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	5,000,000.0			5,000,000.0			4,600,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[7],[13]	45,200,000			45,200,000			69,400,000
Risk Management Liabilities	[7],[13]	100,000			100,000			300,000
Risk Management Assets
Risk Management Assets	[7],[13]	45,200,000			45,200,000			69,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	100,000			100,000			300,000
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets		45,200,000			45,200,000			69,400,000
Risk Management Liabilities		100,000			100,000			300,000
Risk Management Assets
Risk Management Assets		45,200,000			45,200,000			69,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		100,000			100,000			300,000
Appalachian Power Co [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	1.63			1.63			3.89
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	1.63			1.63			3.89
Appalachian Power Co [Member] | FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(3.92)			(3.92)			(2.82)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(3.92)			(3.92)			(2.82)
Appalachian Power Co [Member] | FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	9.08			9.08			18.88
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	9.08			9.08			18.88
Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		10,500,000			10,500,000			9,900,000
Total Assets		5,700,000			5,700,000			8,700,000
Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,539,700,000			3,539,700,000			3,341,200,000
Total Assets		3,560,900,000			3,560,900,000			3,356,600,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		6,800,000		9,800,000	4,600,000		(700,000)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	2,300,000		2,100,000	(1,700,000)		3,700,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0	0		0
Settlements		(3,700,000)		(4,800,000)	(2,900,000)		(3,000,000.0)
Transfers into Level 3	[4],[5]			0	0		0
Transfers out of Level 3	[5]	(100,000)		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	1,300,000		2,500,000	6,600,000		9,600,000
Ending Balance		6,600,000		9,600,000	6,600,000		9,600,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		3,443,600,000			3,443,600,000			3,260,800,000
Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,184,500,000			2,184,500,000			2,142,600,000
Total Assets		2,184,500,000			2,184,500,000			2,142,600,000
Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,344,700,000			1,344,700,000			1,188,700,000
Total Assets		1,362,800,000			1,362,800,000			1,200,000,000
Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Total Assets		7,900,000			7,900,000			5,300,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[7],[13]	(4,800,000)			(4,800,000)			(1,200,000)
Risk Management Liabilities	[7],[13]	(4,400,000)			(4,400,000)			(1,300,000)
Risk Management Assets
Risk Management Assets	[7],[13]	(4,800,000)			(4,800,000)			(1,200,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	(4,400,000)			(4,400,000)			(1,300,000)
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[7],[13]	21,200,000			21,200,000			15,400,000
Risk Management Liabilities	[7],[13]	1,100,000			1,100,000			0
Risk Management Assets
Risk Management Assets	[7],[13]	21,200,000			21,200,000			15,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	1,100,000			1,100,000			0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[7],[13]	0			0			0
Risk Management Liabilities	[7],[13]	0			0			0
Risk Management Assets
Risk Management Assets	[7],[13]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	0			0			0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[7],[13]	18,100,000			18,100,000			11,300,000
Risk Management Liabilities	[7],[13]	4,200,000			4,200,000			600,000
Risk Management Assets
Risk Management Assets	[7],[13]	18,100,000			18,100,000			11,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	4,200,000			4,200,000			600,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[7],[13]	7,900,000			7,900,000			5,300,000
Risk Management Liabilities	[7],[13]	1,300,000			1,300,000			700,000
Risk Management Assets
Risk Management Assets	[7],[13]	7,900,000			7,900,000			5,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	1,300,000			1,300,000			700,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets		7,900,000			7,900,000			5,300,000
Risk Management Liabilities		1,300,000			1,300,000			700,000
Risk Management Assets
Risk Management Assets		7,900,000			7,900,000			5,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		1,300,000			1,300,000			700,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	1.08			1.08			1.23
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	1.08			1.08			1.23
Indiana Michigan Power Co [Member] | FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(4.36)			(4.36)			0.16
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(4.36)			(4.36)			0.16
Indiana Michigan Power Co [Member] | FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	9.08			9.08			18.79
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	9.08			9.08			18.79
Ohio Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		(54,000,000.0)		(48,400,000)	(40,000,000.0)		(92,500,000)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	0		300,000	(2,400,000)		4,600,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0	0		0
Settlements		1,100,000		(1,100,000)	3,500,000		200,000
Transfers into Level 3	[4],[5]			0	0		0
Transfers out of Level 3	[5]	0		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	1,300,000		6,000,000.0	(12,700,000)		44,500,000
Ending Balance		(51,600,000)		(43,200,000)	(51,600,000)		(43,200,000)
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		3,366,200,000			3,366,200,000			2,970,300,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[13]	0			0
Risk Management Liabilities	[13]	0			0			(300,000)	[7]
Risk Management Assets
Risk Management Assets	[13]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[13]	0			0			(300,000)	[7]
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[13]	300,000			300,000
Risk Management Liabilities	[13]	51,600,000			51,600,000			39,700,000
Risk Management Assets
Risk Management Assets	[13]	300,000			300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[13]	51,600,000			51,600,000			39,700,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[13]	0			0
Risk Management Liabilities	[13]	0			0			0
Risk Management Assets
Risk Management Assets	[13]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[13]	0			0			0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[13]	300,000			300,000
Risk Management Liabilities	[13]	0			0			0
Risk Management Assets
Risk Management Assets	[13]	300,000			300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[13]	0			0			0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[13]	0			0
Risk Management Liabilities	[13]	51,600,000			51,600,000			40,000,000.0
Risk Management Assets
Risk Management Assets	[13]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[13]	51,600,000			51,600,000			40,000,000.0
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets		0			0			0
Risk Management Liabilities		51,600,000			51,600,000			40,000,000.0
Risk Management Assets
Risk Management Assets		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		51,600,000			51,600,000			40,000,000.0
Ohio Power Co [Member] | Energy Contracts [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	41.66			41.66			48.76
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	41.66			41.66			48.76
Ohio Power Co [Member] | Energy Contracts [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	19.89			19.89			2.91
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	19.89			19.89			2.91
Ohio Power Co [Member] | Energy Contracts [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	65.40			65.40			187.34
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	65.40			65.40			187.34
Public Service Co Of Oklahoma [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets								(300,000)
Public Service Co Of Oklahoma [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets								25,300,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		43,100,000		64,500,000	23,700,000		12,100,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	14,200,000		23,800,000	3,500,000		24,200,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0	0		0
Settlements		(30,500,000)		(49,100,000)	(27,200,000)		(36,300,000)
Transfers into Level 3	[4],[5]			0	0		0
Transfers out of Level 3	[5]	0		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	400,000		5,200,000	27,200,000		44,400,000
Ending Balance		27,200,000		44,400,000	27,200,000		44,400,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		2,384,200,000			2,384,200,000			1,912,800,000
Public Service Co Of Oklahoma [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets								0
Public Service Co Of Oklahoma [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets								1,600,000
Public Service Co Of Oklahoma [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets								24,000,000.0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[7],[13]	(400,000)			(400,000)			1,300,000
Risk Management Liabilities	[7],[13]	(300,000)			(300,000)			(400,000)
Risk Management Assets
Risk Management Assets	[7],[13]	(400,000)			(400,000)			1,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	(300,000)			(300,000)			(400,000)
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[7],[13]	28,200,000			28,200,000			25,300,000
Risk Management Liabilities	[7],[13]	7,200,000			7,200,000			1,600,000
Risk Management Assets
Risk Management Assets	[7],[13]	28,200,000			28,200,000			25,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	7,200,000			7,200,000			1,600,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[7],[13]	0			0			0
Risk Management Liabilities	[7],[13]	0			0			0
Risk Management Assets
Risk Management Assets	[7],[13]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	0			0			0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[7],[13]	500,000			500,000			0
Risk Management Liabilities	[7],[13]	6,600,000			6,600,000			1,700,000
Risk Management Assets
Risk Management Assets	[7],[13]	500,000			500,000			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	6,600,000			6,600,000			1,700,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[7],[13]	28,100,000			28,100,000			24,000,000.0
Risk Management Liabilities	[7],[13]	900,000			900,000			300,000
Risk Management Assets
Risk Management Assets	[7],[13]	28,100,000			28,100,000			24,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	900,000			900,000			300,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets		28,100,000			28,100,000			24,000,000.0
Risk Management Liabilities		900,000			900,000			300,000
Risk Management Assets
Risk Management Assets		28,100,000			28,100,000			24,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		900,000			900,000			300,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[11]	(4.42)			(4.42)			(7.55)	[10]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[11]	(4.42)			(4.42)			(7.55)	[10]
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit		(17.92)			(17.92)			(36.45)	[10]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit		(17.92)			(17.92)			(36.45)	[10]
Public Service Co Of Oklahoma [Member] | FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit		2.04			2.04			3.40	[10]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit		2.04			2.04			3.40	[10]
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Other [Member]
Risk Management Assets								(1,600,000)
Risk Management Assets
Risk Management Assets								(1,600,000)
Public Service Co Of Oklahoma [Member] | Interest Rate [Member]
Risk Management Assets								0
Risk Management Assets
Risk Management Assets								0
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Level 1 [Member]
Risk Management Assets								0
Risk Management Assets
Risk Management Assets								0
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Level 2 [Member]
Risk Management Assets								1,600,000
Risk Management Assets
Risk Management Assets								1,600,000
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Level 3 [Member]
Risk Management Assets								0
Risk Management Assets
Risk Management Assets								0
Southwestern Electric Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		26,000,000.0		45,400,000	14,200,000		10,900,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	14,000,000.0		15,400,000	5,900,000		35,800,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0	0		0
Settlements		(24,800,000)		(31,600,000)	(20,000,000.0)		(45,000,000.0)
Transfers into Level 3	[4],[5]			0	0		0
Transfers out of Level 3	[5]	0		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	1,300,000		7,000,000.0	16,400,000		34,500,000
Ending Balance		16,500,000		$ 36,200,000	16,500,000		$ 36,200,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		3,646,200,000			3,646,200,000			3,391,600,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[7],[13]	(500,000)			(500,000)			(400,000)
Risk Management Liabilities	[7],[13]	(500,000)			(500,000)			(600,000)
Risk Management Assets
Risk Management Assets	[7],[13]	(500,000)			(500,000)			(400,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	(500,000)			(500,000)			(600,000)
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[7],[13]	17,100,000			17,100,000			16,400,000
Risk Management Liabilities	[7],[13]	3,500,000			3,500,000			1,400,000
Risk Management Assets
Risk Management Assets	[7],[13]	17,100,000			17,100,000			16,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	3,500,000			3,500,000			1,400,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[7],[13]	0			0			0
Risk Management Liabilities	[7],[13]	0			0			0
Risk Management Assets
Risk Management Assets	[7],[13]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	0			0			0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[7],[13]	200,000			200,000			2,200,000
Risk Management Liabilities	[7],[13]	3,100,000			3,100,000			1,600,000
Risk Management Assets
Risk Management Assets	[7],[13]	200,000			200,000			2,200,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	3,100,000			3,100,000			1,600,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[7],[13]	17,400,000			17,400,000			14,600,000
Risk Management Liabilities	[7],[13]	900,000			900,000			400,000
Risk Management Assets
Risk Management Assets	[7],[13]	17,400,000			17,400,000			14,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	900,000			900,000			400,000
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Level 3 [Member]
Risk Management Assets		0			0
Risk Management Liabilities		200,000			200,000
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		200,000			200,000
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[11],[12]	3.55			3.55
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[11],[12]	3.55			3.55
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[12]	3.55			3.55
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]	3.55			3.55
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[12]	3.55			3.55
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]	3.55			3.55
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets		17,400,000			17,400,000			14,600,000
Risk Management Liabilities		700,000			700,000			400,000
Risk Management Assets
Risk Management Assets		17,400,000			17,400,000			14,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		700,000			700,000			400,000
Southwestern Electric Power Co [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(4.42)			(4.42)			(7.55)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(4.42)			(4.42)			(7.55)
Southwestern Electric Power Co [Member] | FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(17.92)			(17.92)			(36.45)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(17.92)			(17.92)			(36.45)
Southwestern Electric Power Co [Member] | FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	2.04			2.04			3.40
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	2.04			2.04			3.40
Cash [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Cash [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		53,800,000			53,800,000			47,100,000
Other Short-term Investments	[14]	53,800,000			53,800,000			47,100,000
Cash [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		53,800,000			53,800,000			47,100,000
Cash [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Cash [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Other Cash Deposits [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[15]	13,400,000			13,400,000			9,000,000.0
Other Cash Deposits [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		13,400,000			13,400,000			9,000,000.0
Other Cash Deposits [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Other Cash Deposits [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Other Cash Deposits [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Mutual Funds Fixed Income [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Mutual Funds Fixed Income [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	160,000,000.0			160,000,000.0			144,100,000
Mutual Funds Fixed Income [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		160,000,000.0			160,000,000.0			144,100,000
Mutual Funds Fixed Income [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Mutual Funds Fixed Income [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Mutual Funds Equity [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[17]	0			0			0
Mutual Funds Equity [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[17]	37,600,000			37,600,000			34,500,000
Mutual Funds Equity [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[17]	37,600,000			37,600,000			34,500,000
Mutual Funds Equity [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[17]	0			0			0
Mutual Funds Equity [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[17]	0			0			0
Cash and Cash Equivalents [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	10,500,000			10,500,000			9,900,000
Cash and Cash Equivalents [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	20,500,000			20,500,000			21,200,000
Cash and Cash Equivalents [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	10,000,000.0			10,000,000.0			11,300,000
Cash and Cash Equivalents [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	0			0			0
Cash and Cash Equivalents [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	0			0			0
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	10,500,000			10,500,000			9,900,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	20,500,000			20,500,000			21,200,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	10,000,000.0			10,000,000.0			11,300,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	0			0			0
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	0			0			0
US Government Agencies Debt Securities [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
US Government Agencies Debt Securities [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,204,700,000			1,204,700,000			1,123,800,000
US Government Agencies Debt Securities [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
US Government Agencies Debt Securities [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,204,700,000			1,204,700,000			1,123,800,000
US Government Agencies Debt Securities [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,204,700,000			1,204,700,000			1,123,800,000
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,204,700,000			1,204,700,000			1,123,800,000
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		136,800,000			136,800,000			61,600,000
Corporate Debt [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		136,800,000			136,800,000			61,600,000
Corporate Debt [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		136,800,000			136,800,000			61,600,000
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		136,800,000			136,800,000			61,600,000
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
State and Local Jurisdiction [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
State and Local Jurisdiction [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,200,000			3,200,000			3,300,000
State and Local Jurisdiction [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
State and Local Jurisdiction [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,200,000			3,200,000			3,300,000
State and Local Jurisdiction [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,200,000			3,200,000			3,300,000
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,200,000			3,200,000			3,300,000
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Fixed Income Funds [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Fixed Income Funds [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,344,700,000			1,344,700,000			1,188,700,000
Fixed Income Funds [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Fixed Income Funds [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,344,700,000			1,344,700,000			1,188,700,000
Fixed Income Funds [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,344,700,000			1,344,700,000			1,188,700,000
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,344,700,000			1,344,700,000			1,188,700,000
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Domestic [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0			0
Domestic [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	2,174,500,000			2,174,500,000			2,131,300,000
Domestic [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	2,174,500,000			2,174,500,000			2,131,300,000
Domestic [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0			0
Domestic [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0			0
Domestic [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0			0
Domestic [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	2,174,500,000			2,174,500,000			2,131,300,000
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	2,174,500,000			2,174,500,000			2,131,300,000
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0			0
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	$ 0			$ 0			$ 0

[1] Included in revenues on the statements of income.

[2] Represents the change in fair value between the beginning of the reporting period and the settlement of the risk management commodity contract.

[3] Included in cash flow hedges on the statements of comprehensive income.

[4] Represents existing assets or liabilities that were previously categorized as Level 2.

[5] Transfers are recognized based on their value at the beginning of the reporting period that the transfer occurred.

[6] Relates to the net gains (losses) of those contracts that are not reflected on the statements of income.  These changes in fair value are recorded as regulatory liabilities for net gains and as regulatory assets for net losses or accounts payable.

[7] Amounts in “Other’’ column primarily represent counterparty netting of risk management and hedging contracts and associated cash collateral under the accounting guidance for “Derivatives and Hedging.’’

[8] The September 30, 2023 maturities of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), were as follows: Level 1 matures $(4) million in 2023 and $(9) million in periods 2024-2026; Level 2 matures $64 million in periods 2024-2026, $10 million in periods 2027-2028 and $1 million in periods 2029-2033; Level 3 matures $37 million in 2023, $118 million in periods 2024-2026, $18 million in periods 2027-2028 and $(9) million in periods 2029-2033.  Risk management commodity contracts are substantially comprised of power contracts.

[9] The December 31, 2022 maturities of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), were as follows: Level 1 matures $(7) million in 2023; Level 2 matures $182 million in 2023, $134 million in periods 2024-2026, $10 million in periods 2027-2028 and $1 million in periods 2029-2033; Level 3 matures $128 million in 2023, $6 million in periods 2024-2026, $6 million in periods 2027-2028 and $(5) million in periods 2029-2033.  Risk management commodity contracts are substantially comprised of power contracts.

[10] Represents market prices in dollars per MWh.

[11] The weighted average is the product of the forward market price of the underlying commodity and volume weighted by term.

[12] Represents market prices in dollars per MMBtu.

[13] Substantially comprised of power contracts for the Registrant Subsidiaries.

[14] Primarily represents amounts held for the repayment of debt.

[15] Amounts in “Other’’ column primarily represent cash deposits in bank accounts with financial institutions or third-parties.  Level 1 and Level 2 amounts primarily represent investments in money market funds.

[16] Primarily short and intermediate maturities which may be sold and do not contain maturity dates.

[17] Amounts represent publicly traded equity securities and equity-based mutual funds.

[18] Amounts in “Other’’ column primarily represent accrued interest receivables from financial institutions.  Level 1 amounts primarily represent investments in money market funds.