Fair Value Assets and Liabilities (Details) - USD ($)		3 Months Ended
		Mar. 31, 2024		Mar. 31, 2023	Dec. 31, 2023
Other [Member]
Risk Management Assets		$ (595,200,000)			$ (625,500,000)
Risk Management Liabilities		(521,600,000)			(608,800,000)
Assets, Fair Value Disclosure
Other Short-term Investments		15,400,000			13,900,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		11,900,000			9,000,000.0
Total Assets		(567,900,000)			(602,600,000)
Risk Management Assets
Risk Management Assets		(595,200,000)			(625,500,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(521,600,000)			(608,800,000)
Risk Management Assets		467,100,000			538,700,000
Risk Management Liabilities		463,900,000			471,400,000
Other Short-term Investments		268,100,000			263,200,000
Spent Nuclear Fuel and Decommissioning Trusts		4,112,600,000			3,860,200,000
Total Assets		4,847,800,000			4,662,100,000
Risk Management Assets		467,100,000			538,700,000
Risk Management Liabilities		463,900,000			471,400,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		139,400,000		$ 160,400,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	46,900,000		(7,100,000)
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	11,300,000		14,800,000
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	600,000		(13,900,000)
Settlements		(96,600,000)		(96,600,000)
Transfers into Level 3	[4],[5]	4,600,000		(6,100,000)
Transfers out of Level 3	[5]	2,100,000		1,000,000.0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	10,800,000		(7,400,000)
Ending Balance		119,100,000		45,100,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		39,835,900,000			40,143,200,000
Level 1 [Member]
Risk Management Assets		3,600,000			9,700,000
Risk Management Liabilities		21,000,000.0			24,700,000
Assets, Fair Value Disclosure
Other Short-term Investments		252,700,000			249,300,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,708,700,000			2,444,400,000
Total Assets		2,965,000,000			2,703,400,000
Risk Management Assets
Risk Management Assets		3,600,000			9,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		21,000,000.0			24,700,000
Level 2 [Member]
Risk Management Assets		782,500,000			860,400,000
Risk Management Liabilities		807,400,000			900,800,000
Assets, Fair Value Disclosure
Other Short-term Investments		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,392,000,000			1,406,800,000
Total Assets		2,174,500,000			2,267,200,000
Risk Management Assets
Risk Management Assets		782,500,000			860,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		807,400,000			900,800,000
Level 3 [Member]
Risk Management Assets		276,200,000			294,100,000
Risk Management Liabilities		157,100,000			154,700,000
Assets, Fair Value Disclosure
Other Short-term Investments		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0
Total Assets		276,200,000			294,100,000
Risk Management Assets
Risk Management Assets		276,200,000			294,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		157,100,000			154,700,000
2024 [Member] | Level 1 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(14,000,000)			(11,000,000)
2024 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(65,000,000)			(99,000,000)
2024 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		34,000,000			74,000,000
2025 - 2027 [Member] | Level 1 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(3,000,000)			(4,000,000)
2025 - 2027 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		51,000,000			(44,000,000)
2025 - 2027 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		55,000,000			43,000,000
2028 - 2029 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		5,000,000			7,000,000
2028 - 2029 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		23,000,000			18,000,000
Maturity Period Four [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities					2,000,000
Maturity Period Four [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(12,000,000)			(16,000,000)
Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[8]	(593,900,000)	[7]		(617,000,000.0)	[9]
Risk Management Liabilities	[8]	(520,300,000)	[7]		(600,300,000)	[9]
Risk Management Assets
Risk Management Assets	[8]	(593,900,000)	[7]		(617,000,000.0)	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(520,300,000)	[7]		(600,300,000)	[9]
Risk Management Commodity Contracts [Member]
Risk Management Assets	[8]	346,900,000	[7]		403,900,000	[9]
Risk Management Liabilities	[8]	346,200,000	[7]		362,300,000	[9]
Risk Management Assets
Risk Management Assets	[8]	346,900,000	[7]		403,900,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	346,200,000	[7]		362,300,000	[9]
Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[8]	3,600,000	[7]		9,700,000	[9]
Risk Management Liabilities	[8]	21,000,000.0	[7]		24,700,000	[9]
Risk Management Assets
Risk Management Assets	[8]	3,600,000	[7]		9,700,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	21,000,000.0	[7]		24,700,000	[9]
Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[8]	679,700,000	[7]		736,900,000	[9]
Risk Management Liabilities	[8]	688,400,000	[7]		783,800,000	[9]
Risk Management Assets
Risk Management Assets	[8]	679,700,000	[7]		736,900,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	688,400,000	[7]		783,800,000	[9]
Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[8]	257,500,000	[7]		274,300,000	[9]
Risk Management Liabilities	[8]	157,100,000	[7]		154,100,000	[9]
Risk Management Assets
Risk Management Assets	[8]	257,500,000	[7]		274,300,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	157,100,000	[7]		154,100,000	[9]
Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets		246,500,000			225,500,000
Risk Management Liabilities		146,100,000			144,900,000
Risk Management Assets
Risk Management Assets		246,500,000			225,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		146,100,000			144,900,000
Energy Contracts [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	49.39			45.05
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	49.39			45.05
Energy Contracts [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	10.31			5.21
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	10.31			5.21
Energy Contracts [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	169.47			153.77
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	169.47			153.77
Natural Gas Contracts [Member] | Level 3 [Member]
Risk Management Assets					0
Risk Management Liabilities					500,000
Risk Management Assets
Risk Management Assets					0
Liabilities, Fair Value Disclosure
Risk Management Liabilities					500,000
Natural Gas Contracts [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[11],[12]				3.11
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[11],[12]				3.11
Natural Gas Contracts [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[12]				3.11
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]				3.11
Natural Gas Contracts [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[12]				3.11
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]				3.11
FTRs [Member] | Level 3 [Member]
Risk Management Assets		29,700,000			68,600,000
Risk Management Liabilities		11,000,000.0			9,300,000
Risk Management Assets
Risk Management Assets		29,700,000			68,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		11,000,000.0			9,300,000
FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(0.35)			0
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(0.35)			0
FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(79.90)			(25.45)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(79.90)			(25.45)
FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	23.79			17.07
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	23.79			17.07
Commodity Hedges [Member] | Other [Member]
Risk Management Assets	[8]	(1,300,000)			(8,500,000)
Risk Management Liabilities	[8]	(1,300,000)			(8,500,000)
Risk Management Assets
Risk Management Assets	[8]	(1,300,000)			(8,500,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(1,300,000)			(8,500,000)
Commodity Hedges [Member]
Risk Management Assets	[8]	111,900,000			134,800,000
Risk Management Liabilities	[8]	1,200,000			1,700,000
Risk Management Assets
Risk Management Assets	[8]	111,900,000			134,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	1,200,000			1,700,000
Commodity Hedges [Member] | Level 1 [Member]
Risk Management Assets	[8]	0			0
Risk Management Liabilities	[8]	0			0
Risk Management Assets
Risk Management Assets	[8]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0
Commodity Hedges [Member] | Level 2 [Member]
Risk Management Assets	[8]	94,500,000			123,500,000
Risk Management Liabilities	[8]	2,500,000			9,600,000
Risk Management Assets
Risk Management Assets	[8]	94,500,000			123,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	2,500,000			9,600,000
Commodity Hedges [Member] | Level 3 [Member]
Risk Management Assets	[8]	18,700,000			19,800,000
Risk Management Liabilities	[8]	0			600,000
Risk Management Assets
Risk Management Assets	[8]	18,700,000			19,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			600,000
Interest Rate [Member] | Other [Member]
Risk Management Assets		0
Risk Management Liabilities		0			0
Risk Management Assets
Risk Management Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Interest Rate [Member]
Risk Management Assets		8,300,000
Risk Management Liabilities		1,700,000			9,000,000.0
Risk Management Assets
Risk Management Assets		8,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		1,700,000			9,000,000.0
Interest Rate [Member] | Level 1 [Member]
Risk Management Assets		0
Risk Management Liabilities		0			0
Risk Management Assets
Risk Management Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Interest Rate [Member] | Level 2 [Member]
Risk Management Assets		8,300,000
Risk Management Liabilities		1,700,000			9,000,000.0
Risk Management Assets
Risk Management Assets		8,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		1,700,000			9,000,000.0
Interest Rate [Member] | Level 3 [Member]
Risk Management Assets		0
Risk Management Liabilities		0			0
Risk Management Assets
Risk Management Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Fair Value Hedges [Member] | Other [Member]
Risk Management Liabilities		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Fair Value Hedges [Member]
Risk Management Liabilities		114,800,000			98,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		114,800,000			98,400,000
Fair Value Hedges [Member] | Level 1 [Member]
Risk Management Liabilities		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Fair Value Hedges [Member] | Level 2 [Member]
Risk Management Liabilities		114,800,000			98,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		114,800,000			98,400,000
Fair Value Hedges [Member] | Level 3 [Member]
Risk Management Liabilities		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
AEP Texas Inc. [Member] | Other [Member]
Risk Management Assets		0
Risk Management Liabilities		0			(200,000)
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		0
Risk Management Assets
Risk Management Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			(200,000)
AEP Texas Inc. [Member]
Risk Management Assets		2,500,000
Risk Management Liabilities		100,000			2,700,000
Assets, Fair Value Disclosure
Cash and Cash Equivalents		42,700,000			34,000,000.0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		45,200,000
Risk Management Assets
Risk Management Assets		2,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		100,000			2,700,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		5,878,700,000			5,889,800,000
AEP Texas Inc. [Member] | Level 1 [Member]
Risk Management Assets		0
Risk Management Liabilities		0			0
Assets, Fair Value Disclosure
Cash and Cash Equivalents		42,700,000			34,000,000.0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		42,700,000
Risk Management Assets
Risk Management Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
AEP Texas Inc. [Member] | Level 2 [Member]
Risk Management Assets		2,500,000
Risk Management Liabilities		100,000			2,900,000
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		2,500,000
Risk Management Assets
Risk Management Assets		2,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		100,000			2,900,000
AEP Texas Inc. [Member] | Level 3 [Member]
Risk Management Assets		0
Risk Management Liabilities		0			0
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		0
Risk Management Assets
Risk Management Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[8]	2,300,000
Risk Management Liabilities	[8]	100,000			(200,000)
Risk Management Assets
Risk Management Assets	[8]	2,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	100,000			(200,000)
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[8]	2,500,000
Risk Management Liabilities	[8]	100,000			0
Risk Management Assets
Risk Management Assets	[8]	2,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	100,000			0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[8]	0
Risk Management Liabilities	[8]	0			0
Risk Management Assets
Risk Management Assets	[8]	0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[8]	200,000
Risk Management Liabilities	[8]	0			200,000
Risk Management Assets
Risk Management Assets	[8]	200,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			200,000
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[8]	0
Risk Management Liabilities	[8]	0			0
Risk Management Assets
Risk Management Assets	[8]	0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0
AEP Texas Inc. [Member] | Interest Rate [Member] | Other [Member]
Risk Management Assets		(2,300,000)
Risk Management Liabilities		(100,000)			0
Risk Management Assets
Risk Management Assets		(2,300,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(100,000)			0
AEP Texas Inc. [Member] | Interest Rate [Member]
Risk Management Assets		0
Risk Management Liabilities		0			2,700,000
Risk Management Assets
Risk Management Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			2,700,000
AEP Texas Inc. [Member] | Interest Rate [Member] | Level 1 [Member]
Risk Management Assets		0
Risk Management Liabilities		0			0
Risk Management Assets
Risk Management Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
AEP Texas Inc. [Member] | Interest Rate [Member] | Level 2 [Member]
Risk Management Assets		2,300,000
Risk Management Liabilities		100,000			2,700,000
Risk Management Assets
Risk Management Assets		2,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		100,000			2,700,000
AEP Texas Inc. [Member] | Interest Rate [Member] | Level 3 [Member]
Risk Management Assets		0
Risk Management Liabilities		0			0
Risk Management Assets
Risk Management Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
AEP Transmission Co [Member]
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		5,860,700,000			5,414,400,000
Appalachian Power Co [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		(2,000,000.0)			(2,200,000)
Appalachian Power Co [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		8,400,000			14,900,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		17,100,000			37,300,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		22,400,000		69,100,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	9,200,000		(31,900,000)
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0
Settlements		(26,800,000)		(27,300,000)
Transfers into Level 3	[4],[5]	0		0
Transfers out of Level 3	[5]	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	(800,000)		(4,200,000)
Ending Balance		4,000,000.0		5,700,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		5,670,900,000			5,588,300,000
Appalachian Power Co [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		8,400,000			14,900,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		8,400,000			14,900,000
Appalachian Power Co [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		2,100,000			1,100,000
Appalachian Power Co [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		8,600,000			23,500,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[8]	(2,000,000.0)			(2,200,000)
Risk Management Liabilities	[8]	(3,400,000)			(2,600,000)
Risk Management Assets
Risk Management Assets	[8]	(2,000,000.0)			(2,200,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(3,400,000)			(2,600,000)
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[8]	8,700,000			22,400,000
Risk Management Liabilities	[8]	20,500,000			22,500,000
Risk Management Assets
Risk Management Assets	[8]	8,700,000			22,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	20,500,000			22,500,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[8]	0			0
Risk Management Liabilities	[8]	0			0
Risk Management Assets
Risk Management Assets	[8]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[8]	2,100,000			1,100,000
Risk Management Liabilities	[8]	19,300,000			24,000,000.0
Risk Management Assets
Risk Management Assets	[8]	2,100,000			1,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	19,300,000			24,000,000.0
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[8]	8,600,000			23,500,000
Risk Management Liabilities	[8]	4,600,000			1,100,000
Risk Management Assets
Risk Management Assets	[8]	8,600,000			23,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	4,600,000			1,100,000
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets		8,600,000			23,500,000
Risk Management Liabilities		4,600,000			1,100,000
Risk Management Assets
Risk Management Assets		8,600,000			23,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		4,600,000			1,100,000
Appalachian Power Co [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.61			1.36
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.61			1.36
Appalachian Power Co [Member] | FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(0.38)			(1.04)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(0.38)			(1.04)
Appalachian Power Co [Member] | FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	5.05			6.45
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	5.05			6.45
Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		11,900,000			9,000,000.0
Total Assets		8,200,000			6,700,000
Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		4,112,600,000			3,860,200,000
Total Assets		4,123,800,000			3,899,800,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		2,800,000		4,600,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	3,200,000		1,200,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0
Settlements		(4,800,000)		(4,200,000)
Transfers into Level 3	[4],[5]	0		0
Transfers out of Level 3	[5]	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	(200,000)		(500,000)
Ending Balance		1,000,000.0		1,100,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		3,478,500,000			3,499,400,000
Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,708,700,000			2,444,400,000
Total Assets		2,708,700,000			2,444,400,000
Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,392,000,000			1,406,800,000
Total Assets		1,405,100,000			1,444,200,000
Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0
Total Assets		1,800,000			4,500,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[8]	(3,700,000)			(2,300,000)
Risk Management Liabilities	[8]	(7,700,000)			(3,400,000)
Risk Management Assets
Risk Management Assets	[8]	(3,700,000)			(2,300,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(7,700,000)			(3,400,000)
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[8]	11,200,000			39,600,000
Risk Management Liabilities	[8]	700,000			2,000,000.0
Risk Management Assets
Risk Management Assets	[8]	11,200,000			39,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	700,000			2,000,000.0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[8]	0			0
Risk Management Liabilities	[8]	0			0
Risk Management Assets
Risk Management Assets	[8]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[8]	13,100,000			37,400,000
Risk Management Liabilities	[8]	7,600,000			3,700,000
Risk Management Assets
Risk Management Assets	[8]	13,100,000			37,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	7,600,000			3,700,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[8]	1,800,000			4,500,000
Risk Management Liabilities	[8]	800,000			1,700,000
Risk Management Assets
Risk Management Assets	[8]	1,800,000			4,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	800,000			1,700,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets		1,800,000			4,500,000
Risk Management Liabilities		800,000			1,700,000
Risk Management Assets
Risk Management Assets		1,800,000			4,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		800,000			1,700,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.84			(0.85)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.84			(0.85)
Indiana Michigan Power Co [Member] | FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	0.03			(1.48)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	0.03			(1.48)
Indiana Michigan Power Co [Member] | FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	6.82			8.40
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	6.82			8.40
Ohio Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		(50,600,000)		(40,000,000.0)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	(400,000)		(1,300,000)
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0
Settlements		2,600,000		1,000,000.0
Transfers into Level 3	[4],[5]	0		0
Transfers out of Level 3	[5]	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	7,400,000		(6,600,000)
Ending Balance		(41,000,000.0)		(46,900,000)
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		3,367,400,000			3,366,800,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[8]	0
Risk Management Liabilities	[8]	0			(100,000)
Risk Management Assets
Risk Management Assets	[8]	0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			(100,000)
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[8]	100,000
Risk Management Liabilities		41,000,000.0	[8]		50,700,000
Risk Management Assets
Risk Management Assets	[8]	100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		41,000,000.0	[8]		50,700,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[8]	0
Risk Management Liabilities		0	[8]		0
Risk Management Assets
Risk Management Assets	[8]	0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0	[8]		0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[8]	100,000
Risk Management Liabilities		0	[8]		200,000
Risk Management Assets
Risk Management Assets	[8]	100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0	[8]		200,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[8]	0
Risk Management Liabilities		41,000,000.0	[8]		50,600,000
Risk Management Assets
Risk Management Assets	[8]	0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		41,000,000.0	[8]		50,600,000
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets		0			0
Risk Management Liabilities		41,000,000.0			50,600,000
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		41,000,000.0			50,600,000
Ohio Power Co [Member] | Energy Contracts [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	47.20			42.85
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	47.20			42.85
Ohio Power Co [Member] | Energy Contracts [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	19.72			22.92
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	19.72			22.92
Ohio Power Co [Member] | Energy Contracts [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	75.88			67.53
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	75.88			67.53
Public Service Co Of Oklahoma [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		18,600,000		23,700,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	18,500,000		16,600,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0
Settlements		(31,300,000)		(34,300,000)
Transfers into Level 3	[4],[5]	0		0
Transfers out of Level 3	[5]	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	1,900,000		3,300,000
Ending Balance		7,700,000		9,300,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		2,384,900,000			2,384,600,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[8]	(600,000)			(700,000)
Risk Management Liabilities	[8]	(600,000)			(800,000)
Risk Management Assets
Risk Management Assets	[8]	(600,000)			(700,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(600,000)			(800,000)
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[8]	7,900,000			19,000,000.0
Risk Management Liabilities	[8]	31,300,000			29,900,000
Risk Management Assets
Risk Management Assets	[8]	7,900,000			19,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	31,300,000			29,900,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[8]	0			0
Risk Management Liabilities	[8]	0			0
Risk Management Assets
Risk Management Assets	[8]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[8]	100,000			0
Risk Management Liabilities	[8]	31,200,000			29,600,000
Risk Management Assets
Risk Management Assets	[8]	100,000			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	31,200,000			29,600,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[8]	8,400,000			19,700,000
Risk Management Liabilities	[8]	700,000			1,100,000
Risk Management Assets
Risk Management Assets	[8]	8,400,000			19,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	700,000			1,100,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets		8,400,000			19,700,000
Risk Management Liabilities		700,000			1,100,000
Risk Management Assets
Risk Management Assets		8,400,000			19,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		700,000			1,100,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(3.48)			(4.33)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(3.48)			(4.33)
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(79.90)			(25.45)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(79.90)			(25.45)
Public Service Co Of Oklahoma [Member] | FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	3.13			4.80
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	3.13			4.80
Southwestern Electric Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		11,100,000		14,200,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	14,700,000		12,900,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0
Settlements		(23,600,000)		(23,000,000.0)
Transfers into Level 3	[4],[5]	0		0
Transfers out of Level 3	[5]	500,000		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	2,600,000		1,700,000
Ending Balance		5,300,000		$ 5,800,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		3,647,600,000			3,646,900,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[8]	(300,000)			(900,000)
Risk Management Liabilities	[8]	(200,000)			(1,000,000.0)
Risk Management Assets
Risk Management Assets	[8]	(300,000)			(900,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(200,000)			(1,000,000.0)
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[8]	5,300,000			11,600,000
Risk Management Liabilities	[8]	11,100,000			15,600,000
Risk Management Assets
Risk Management Assets	[8]	5,300,000			11,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	11,100,000			15,600,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[8]	0			0
Risk Management Liabilities	[8]	0			0
Risk Management Assets
Risk Management Assets	[8]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[8]	100,000			500,000
Risk Management Liabilities	[8]	11,100,000			15,700,000
Risk Management Assets
Risk Management Assets	[8]	100,000			500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	11,100,000			15,700,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[8]	5,500,000			12,000,000.0
Risk Management Liabilities	[8]	200,000			900,000
Risk Management Assets
Risk Management Assets	[8]	5,500,000			12,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	200,000			900,000
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Level 3 [Member]
Risk Management Assets					0
Risk Management Liabilities					500,000
Risk Management Assets
Risk Management Assets					0
Liabilities, Fair Value Disclosure
Risk Management Liabilities					500,000
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]				3.11
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[11],[12]				3.11
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[12]				3.11
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]				3.11
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[12]				3.11
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]				3.11
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets		5,500,000			12,000,000.0
Risk Management Liabilities		200,000			400,000
Risk Management Assets
Risk Management Assets		5,500,000			12,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		200,000			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]	(3.48)			(4.33)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(3.48)			(4.33)
Southwestern Electric Power Co [Member] | FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(79.90)			(25.45)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(79.90)			(25.45)
Southwestern Electric Power Co [Member] | FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	3.13			4.80
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	3.13			4.80
Cash [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Cash [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		51,100,000			48,900,000
Other Short-term Investments	[13]	51,100,000			48,900,000
Cash [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		51,100,000			48,900,000
Cash [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Cash [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Other Cash Deposits [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[14]	15,400,000			13,900,000
Other Cash Deposits [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		15,400,000			13,900,000
Other Cash Deposits [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0
Other Cash Deposits [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0
Other Cash Deposits [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0
Mutual Funds Fixed Income [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0
Mutual Funds Fixed Income [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[15]	157,900,000			159,700,000
Mutual Funds Fixed Income [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		157,900,000			159,700,000
Mutual Funds Fixed Income [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0
Mutual Funds Fixed Income [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0
Mutual Funds Equity [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	0			0
Mutual Funds Equity [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	43,700,000			40,700,000
Mutual Funds Equity [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	43,700,000			40,700,000
Mutual Funds Equity [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	0			0
Mutual Funds Equity [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	0			0
Cash and Cash Equivalents [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	11,900,000			9,000,000.0
Cash and Cash Equivalents [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	25,200,000			16,800,000
Cash and Cash Equivalents [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	13,300,000			7,800,000
Cash and Cash Equivalents [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0
Cash and Cash Equivalents [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	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	[17]	11,900,000			9,000,000.0
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	25,200,000			16,800,000
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	[17]	13,300,000			7,800,000
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	[17]	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	[17]	0			0
US Government Agencies Debt Securities [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0
US Government Agencies Debt Securities [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,267,000,000			1,273,000,000
US Government Agencies Debt Securities [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0
US Government Agencies Debt Securities [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,267,000,000			1,273,000,000
US Government Agencies Debt Securities [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		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
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,267,000,000			1,273,000,000
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
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		1,267,000,000			1,273,000,000
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
Corporate Debt [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0
Corporate Debt [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		123,300,000			132,100,000
Corporate Debt [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0
Corporate Debt [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		123,300,000			132,100,000
Corporate Debt [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		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
Corporate Debt [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		123,300,000			132,100,000
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
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		123,300,000			132,100,000
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
State and Local Jurisdiction [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0
State and Local Jurisdiction [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,700,000			1,700,000
State and Local Jurisdiction [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0
State and Local Jurisdiction [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,700,000			1,700,000
State and Local Jurisdiction [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		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
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,700,000			1,700,000
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
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		1,700,000			1,700,000
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
Fixed Income Funds [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0
Fixed Income Funds [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,392,000,000			1,406,800,000
Fixed Income Funds [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0
Fixed Income Funds [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,392,000,000			1,406,800,000
Fixed Income Funds [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		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
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,392,000,000			1,406,800,000
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
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,392,000,000			1,406,800,000
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
Domestic [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	0			0
Domestic [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,695,400,000			2,436,600,000
Domestic [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,695,400,000			2,436,600,000
Domestic [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	0			0
Domestic [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	0			0
Domestic [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	0			0
Domestic [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,695,400,000			2,436,600,000
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,695,400,000			2,436,600,000
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	0			0
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	$ 0			$ 0

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

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

[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] The March 31, 2024 maturities of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), were as follows: Level 1 matures $(14) million in 2024 and $(3) million in periods 2025-2027; Level 2 matures $(65) million in 2024, $51 million in periods 2025-2027 and $5 million in periods 2028-2029; Level 3 matures $34 million in 2024, $55 million in periods 2025-2027, $23 million in periods 2028-2029 and $(12) million in periods 2030-2032.  Risk management commodity contracts are substantially comprised of power contracts.

[8] 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.’’

[9] The December 31, 2023 maturities of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), were as follows: Level 1 matures $(11) million in 2024 and $(4) million in 2025-2027; Level 2 matures $(99) million in 2024, $(44) million in periods 2025-2027, $7 million in periods 2028-2029 and $2 million in periods 2030-2033; Level 3 matures $74 million in 2024, $43 million in periods 2025-2027, $18 million in periods 2028-2029 and $(16) million in periods 2030-2033.  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] Primarily represents amounts held for the repayment of debt.

[14] 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.

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

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

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