Fair Value Assets and Liabilities (Details) - USD ($)		3 Months Ended
		Mar. 31, 2023		Mar. 31, 2022	Dec. 31, 2022
Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		$ 11,400,000			$ 9,000,000.0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		9,400,000			9,900,000
Total Assets		(760,800,000)			(1,245,400,000)
Risk Management Assets
Risk Management Assets		(781,600,000)			(1,264,300,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(688,900,000)			(784,700,000)
Other Short-term Investments		244,600,000			234,700,000
Spent Nuclear Fuel and Decommissioning Trusts		3,501,100,000			3,341,200,000
Total Assets		4,254,500,000			4,208,800,000
Risk Management Assets		508,800,000			632,900,000
Risk Management Liabilities		481,400,000			490,400,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		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]	(7,100,000)		18,200,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	14,800,000		(19,000,000.0)
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	(13,900,000)		19,300,000
Settlements		(96,600,000)		(51,600,000)
Transfers into Level 3	[4],[5]	(6,100,000)		2,500,000
Transfers out of Level 3	[5]	1,000,000.0		2,900,000
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	(7,400,000)		7,400,000
Ending Balance		45,100,000		82,800,000
Fair Value Measurements 1 (Textuals)
Assets Held for Sale		1,396,300,000			0
Liabilities Held for Sale		67,200,000			0
Total Long-term Debt Outstanding		39,144,200,000			36,801,000,000
Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		233,200,000			225,700,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,214,800,000			2,142,600,000
Total Assets		2,461,000,000			2,383,300,000
Risk Management Assets
Risk Management Assets		13,000,000.0			15,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		33,500,000			21,800,000
Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,276,900,000			1,188,700,000
Total Assets		2,324,800,000			2,729,800,000
Risk Management Assets
Risk Management Assets		1,047,900,000			1,541,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		952,400,000			1,072,600,000
Level 3 [Member]
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		229,500,000			341,100,000
Risk Management Assets
Risk Management Assets		229,500,000			341,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		184,400,000			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		(14,000,000)			(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		24,000,000			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		18,000,000			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		(6,000,000)
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		105,000,000			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		9,000,000			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		9,000,000			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		11,000,000			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
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		(7,000,000)			(5,000,000)
Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7]	(720,200,000)	[8]		(1,211,500,000)	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	(627,500,000)	[8]		(731,900,000)	[9]
Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7]	363,200,000	[8]		315,400,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	305,600,000	[8]		339,800,000	[9]
Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7]	13,000,000.0	[8]		15,000,000.0	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	33,500,000	[8]		21,800,000	[9]
Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7]	861,200,000	[8]		1,197,500,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	721,100,000	[8]		870,900,000	[9]
Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7]	209,200,000	[8]		314,400,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	178,500,000	[8]		179,000,000.0	[9]
Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		190,700,000			204,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		166,500,000			167,400,000
Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	0.74			2.91
Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	101.65			187.34
Energy Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	48.48			49.14
FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		38,800,000			137,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		17,900,000			13,300,000
FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(55.98)			(36.45)
FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	101.82			20.72
FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(0.45)			1.18
Commodity Hedges [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7]	(61,400,000)			(52,800,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	(61,400,000)			(52,800,000)
Commodity Hedges [Member]
Risk Management Assets
Risk Management Assets	[7]	136,700,000			306,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	53,600,000			23,200,000
Commodity Hedges [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	0			0
Commodity Hedges [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7]	177,800,000			332,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	109,100,000			74,300,000
Commodity Hedges [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7]	20,300,000			26,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	5,900,000			1,700,000
Interest Rate [Member] | Other [Member]
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0
Interest Rate [Member]
Risk Management Assets
Risk Management Assets		8,900,000			11,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		1,700,000
Interest Rate [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0
Interest Rate [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets		8,900,000			11,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		1,700,000
Interest Rate [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0
Fair Value Hedges [Member] | Other [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Fair Value Hedges [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities		120,500,000			127,400,000
Fair Value Hedges [Member] | Level 1 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Fair Value Hedges [Member] | Level 2 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities		120,500,000			127,400,000
Fair Value Hedges [Member] | Level 3 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
AEP Texas Inc. [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(400,000)
AEP Texas Inc. [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		42,500,000			32,700,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		43,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		800,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		5,522,000,000			5,657,800,000
AEP Texas Inc. [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		42,500,000			32,700,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		42,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0
AEP Texas Inc. [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		1,200,000
AEP Texas Inc. [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	(400,000)
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	400,000
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	0
AEP Texas Inc. [Member] | Interest Rate [Member] | Other [Member]
Risk Management Assets
Risk Management Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0
AEP Texas Inc. [Member] | Interest Rate [Member]
Risk Management Assets
Risk Management Assets		500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		800,000
AEP Texas Inc. [Member] | Interest Rate [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0
AEP Texas Inc. [Member] | Interest Rate [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets		500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		800,000
AEP Texas Inc. [Member] | Interest Rate [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0
AEP Transmission Co [Member]
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		5,472,100,000			4,782,800,000
Appalachian Power Co [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		(400,000)			(1,000,000.0)
Appalachian Power Co [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		7,500,000			14,400,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		19,900,000			83,500,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		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]	(31,900,000)		(2,900,000)
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0
Settlements		(27,300,000)		(32,400,000)
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]	(4,200,000)		200,000
Ending Balance		5,700,000		6,600,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		5,398,700,000			5,410,500,000
Appalachian Power Co [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		7,500,000			14,400,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		7,500,000			14,400,000
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		400,000			700,000
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		12,400,000			69,400,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	(400,000)			(1,000,000.0)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	(600,000)			(1,400,000)
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	12,400,000			69,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	7,000,000.0			3,500,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	0			0
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	400,000			700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	900,000			4,600,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	12,400,000			69,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	6,700,000			300,000
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		12,400,000			69,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		6,700,000			300,000
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(1.67)			(2.82)
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	6.59			18.88
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.79			3.89
Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		9,400,000			9,900,000
Total Assets		8,200,000			8,700,000
Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,501,100,000			3,341,200,000
Total Assets		3,508,100,000			3,356,600,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		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]	1,200,000		3,800,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0
Settlements		(4,200,000)		(2,300,000)
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]	(500,000)		200,000
Ending Balance		1,100,000		1,000,000.0
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		3,489,000,000			3,260,800,000
Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,214,800,000			2,142,600,000
Total Assets		2,214,800,000			2,142,600,000
Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,276,900,000			1,188,700,000
Total Assets		1,283,500,000			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
Total Assets		1,600,000			5,300,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	(1,200,000)			(1,200,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	(1,400,000)			(1,300,000)
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	7,000,000.0			15,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	400,000			0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	0			0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	6,600,000			11,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	1,300,000			600,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	1,600,000			5,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	500,000			700,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		1,600,000			5,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		500,000			700,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	0.24			0.16
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	4.75			18.79
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.78			1.23
Ohio Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		(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]	(1,300,000)		500,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0
Settlements		1,000,000.0		1,400,000
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]	(6,600,000)		22,100,000
Ending Balance		(46,900,000)		(68,500,000)
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		2,970,800,000			2,970,300,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[12]	(200,000)			(300,000)
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[12]	46,900,000			39,700,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[12]	0			0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[12]	200,000			0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[12]	46,900,000			40,000,000.0
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		46,900,000			40,000,000.0
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	14.41			2.91
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	79.98			187.34
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	45.92			48.76
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		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]	16,600,000		12,100,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0
Settlements		(34,300,000)		(19,800,000)
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]	3,300,000		2,100,000
Ending Balance		9,300,000		6,500,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		2,383,600,000			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
Risk Management Assets	[7],[12]	(500,000)			1,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	(700,000)			(400,000)
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	9,400,000			25,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	1,100,000			1,600,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	0			0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	1,200,000			1,700,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	9,900,000			24,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	600,000			300,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		9,900,000			24,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		600,000			300,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(21.10)			(36.45)
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	3.04			3.40
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(4.75)			(7.55)
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Other [Member]
Risk Management Assets
Risk Management Assets					(1,600,000)
Public Service Co Of Oklahoma [Member] | Interest Rate [Member]
Risk Management Assets
Risk Management Assets					0
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets					0
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets					1,600,000
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Level 3 [Member]
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		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]	12,900,000		9,800,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0
Settlements		(23,000,000.0)		(16,200,000)
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]	1,700,000		11,200,000
Ending Balance		5,800,000		$ 15,700,000
Fair Value Measurements 1 (Textuals)
Total Long-term Debt Outstanding		3,644,800,000			3,391,600,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	(100,000)			(400,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	(300,000)			(600,000)
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	6,300,000			16,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	1,100,000			1,400,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	0			0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	0			2,200,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	800,000			1,600,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[12]	6,400,000			14,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[12]	600,000			400,000
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		6,400,000			14,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		600,000			400,000
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(21.10)			(36.45)
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	3.04			3.40
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(4.75)			(7.55)
Cash [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents	[13]	0			0
Cash [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents	[13]	50,000,000.0			47,100,000
Other Short-term Investments	[14]	50,000,000.0			47,100,000
Cash [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents	[13]	50,000,000.0			47,100,000
Cash [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents	[13]	0			0
Cash [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents	[13]	0			0
Other Cash Deposits [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		11,400,000			9,000,000.0
Other Cash Deposits [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		11,400,000			9,000,000.0
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]	146,200,000			144,100,000
Mutual Funds Fixed Income [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		146,200,000			144,100,000
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]	37,000,000.0			34,500,000
Mutual Funds Equity [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	37,000,000.0			34,500,000
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]	9,400,000			9,900,000
Cash and Cash Equivalents [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	26,500,000			21,200,000
Cash and Cash Equivalents [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	17,100,000			11,300,000
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]	9,400,000			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	[17]	26,500,000			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	[17]	17,100,000			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	[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		1,207,600,000			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
US Government Agencies Debt Securities [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,207,600,000			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
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		1,207,600,000			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
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		1,207,600,000			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
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		66,000,000.0			61,600,000
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		66,000,000.0			61,600,000
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		66,000,000.0			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
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		66,000,000.0			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
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		3,300,000			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
State and Local Jurisdiction [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,300,000			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
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		3,300,000			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
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		3,300,000			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
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		1,276,900,000			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
Fixed Income Funds [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,276,900,000			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
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		1,276,900,000			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
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,276,900,000			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
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]	2,197,700,000			2,131,300,000
Domestic [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,197,700,000			2,131,300,000
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]	2,197,700,000			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	[16]	2,197,700,000			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	[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] 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 March 31, 2023 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 2023 and $(6) million in periods 2024-2026; Level 2 matures $24 million in 2023, $105 million in periods 2024-2026, $9 million in periods 2027-2028 and $1 million in periods 2029-2033; Level 3 matures $18 million in 2023, $9 million in periods 2024-2026, $11 million in periods 2027-2028 and $(7) 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] Substantially comprised of power contracts for the Registrant Subsidiaries.

[13] 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.

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

[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.