Fair Value Financial Assets Liabilities (Details) - USD ($)		12 Months Ended
		Dec. 31, 2023		Dec. 31, 2022		Dec. 31, 2021
Derivative Assets		$ 538,700,000		$ 632,900,000
Derivative Liabilities		471,400,000		490,400,000
Assets, Fair Value Disclosure
Other Temporary Investments		263,200,000		234,700,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,860,200,000		3,341,200,000
Total Assets		4,662,100,000		4,208,800,000
Risk Management Assets
Derivative Assets		538,700,000		632,900,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		471,400,000		490,400,000
Changes in the Fair Value of Net Trading Derivatives and Other Investments
Beginning Balance		160,400,000		103,100,000		$ 113,300,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	52,100,000		69,500,000		48,600,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	71,100,000		(34,900,000)		(45,200,000)
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	(17,400,000)		9,600,000		24,200,000
Settlements		(172,200,000)		(154,600,000)		(89,000,000.0)
Transfers into Level 3	[4],[5]	(6,100,000)		1,700,000		(3,800,000)
Transfers out of Level 3	[5]	3,800,000		100,000		(34,400,000)
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	47,700,000		165,900,000		89,400,000
Ending Balance		139,400,000		160,400,000		103,100,000
Other [Member]
Derivative Assets		(625,500,000)		(1,264,300,000)
Derivative Liabilities		(608,800,000)		(784,700,000)
Assets, Fair Value Disclosure
Other Temporary Investments		13,900,000		9,000,000.0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		9,000,000.0		9,900,000
Total Assets		(602,600,000)		(1,245,400,000)
Risk Management Assets
Derivative Assets		(625,500,000)		(1,264,300,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities		(608,800,000)		(784,700,000)
Level 1 [Member]
Derivative Assets		9,700,000		15,000,000.0
Derivative Liabilities		24,700,000		21,800,000
Assets, Fair Value Disclosure
Other Temporary Investments		249,300,000		225,700,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,444,400,000		2,142,600,000
Total Assets		2,703,400,000		2,383,300,000
Risk Management Assets
Derivative Assets		9,700,000		15,000,000.0
Liabilities, Fair Value Disclosure
Derivative Liabilities		24,700,000		21,800,000
Level 2 [Member]
Derivative Assets		860,400,000		1,541,100,000
Derivative Liabilities		900,800,000		1,072,600,000
Assets, Fair Value Disclosure
Other Temporary Investments		0		0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,406,800,000		1,188,700,000
Total Assets		2,267,200,000		2,729,800,000
Risk Management Assets
Derivative Assets		860,400,000		1,541,100,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		900,800,000		1,072,600,000
Level 3 [Member]
Derivative Assets		294,100,000		341,100,000
Derivative Liabilities		154,700,000		180,700,000
Assets, Fair Value Disclosure
Other Temporary Investments		0		0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0		0
Total Assets		294,100,000		341,100,000
Risk Management Assets
Derivative Assets		294,100,000		341,100,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		154,700,000		180,700,000
2023 [Member] | Level 1 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities				(7,000,000)
2023 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities				182,000,000
2023 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities				128,000,000
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		(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		(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		74,000,000
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				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				6,000,000
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		(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		(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		43,000,000
2027 - 2028 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities				10,000,000
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				6,000,000
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		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		18,000,000
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
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				(5,000,000)
2030 - 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		2,000,000
2030 - 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		(16,000,000)
Risk Management Commodity Contracts [Member]
Derivative Assets	[8]	403,900,000	[7]	315,400,000	[9]
Derivative Liabilities	[8]	362,300,000	[7]	339,800,000	[9]
Risk Management Assets
Derivative Assets	[8]	403,900,000	[7]	315,400,000	[9]
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	362,300,000	[7]	339,800,000	[9]
Risk Management Commodity Contracts [Member] | Other [Member]
Derivative Assets	[8]	(617,000,000.0)	[7]	(1,211,500,000)	[9]
Derivative Liabilities	[8]	(600,300,000)	[7]	(731,900,000)	[9]
Risk Management Assets
Derivative Assets	[8]	(617,000,000.0)	[7]	(1,211,500,000)	[9]
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	(600,300,000)	[7]	(731,900,000)	[9]
Risk Management Commodity Contracts [Member] | Level 1 [Member]
Derivative Assets	[8]	9,700,000	[7]	15,000,000.0	[9]
Derivative Liabilities	[8]	24,700,000	[7]	21,800,000	[9]
Risk Management Assets
Derivative Assets	[8]	9,700,000	[7]	15,000,000.0	[9]
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	24,700,000	[7]	21,800,000	[9]
Risk Management Commodity Contracts [Member] | Level 2 [Member]
Derivative Assets	[8]	736,900,000	[7]	1,197,500,000	[9]
Derivative Liabilities	[8]	783,800,000	[7]	870,900,000	[9]
Risk Management Assets
Derivative Assets	[8]	736,900,000	[7]	1,197,500,000	[9]
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	783,800,000	[7]	870,900,000	[9]
Risk Management Commodity Contracts [Member] | Level 3 [Member]
Derivative Assets	[8]	274,300,000	[7]	314,400,000	[9]
Derivative Liabilities	[8]	154,100,000	[7]	179,000,000.0	[9]
Risk Management Assets
Derivative Assets	[8]	274,300,000	[7]	314,400,000	[9]
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	154,100,000	[7]	179,000,000.0	[9]
Energy Contracts [Member] | Level 3 [Member]
Derivative Assets		225,500,000		204,000,000.0
Derivative Liabilities		144,900,000		167,400,000
Risk Management Assets
Derivative Assets		225,500,000		204,000,000.0
Liabilities, Fair Value Disclosure
Derivative Liabilities		144,900,000		167,400,000
Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	5.21		2.91
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	5.21		2.91
Energy Contracts [Member] | Level 3 [Member] | High [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	153.77		187.34
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	153.77		187.34
Energy Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	45.05		49.14
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	45.05		49.14
Natural Gas Contracts [Member] | Level 3 [Member]
Derivative Assets		0
Derivative Liabilities		500,000
Risk Management Assets
Derivative Assets		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		500,000
Natural Gas Contracts [Member] | Level 3 [Member] | Low [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] | Level 3 [Member] | High [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] | Level 3 [Member] | Weighted Average [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
FTRs [Member] | Level 3 [Member]
Derivative Assets		68,600,000		137,100,000
Derivative Liabilities		9,300,000		13,300,000
Risk Management Assets
Derivative Assets		68,600,000		137,100,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		9,300,000		13,300,000
FTRs [Member] | Level 3 [Member] | Low [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(25.45)		(36.45)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(25.45)		(36.45)
FTRs [Member] | Level 3 [Member] | High [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	17.07		20.72
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	17.07		20.72
FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0		1.18
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0		1.18
Commodity Hedges [Member]
Derivative Assets	[8]	134,800,000		306,500,000
Derivative Liabilities	[8]	1,700,000		23,200,000
Risk Management Assets
Derivative Assets	[8]	134,800,000		306,500,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	1,700,000		23,200,000
Commodity Hedges [Member] | Other [Member]
Derivative Assets	[8]	(8,500,000)		(52,800,000)
Derivative Liabilities	[8]	(8,500,000)		(52,800,000)
Risk Management Assets
Derivative Assets	[8]	(8,500,000)		(52,800,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	(8,500,000)		(52,800,000)
Commodity Hedges [Member] | Level 1 [Member]
Derivative Assets	[8]	0		0
Derivative Liabilities	[8]	0		0
Risk Management Assets
Derivative Assets	[8]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	0		0
Commodity Hedges [Member] | Level 2 [Member]
Derivative Assets	[8]	123,500,000		332,600,000
Derivative Liabilities	[8]	9,600,000		74,300,000
Risk Management Assets
Derivative Assets	[8]	123,500,000		332,600,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	9,600,000		74,300,000
Commodity Hedges [Member] | Level 3 [Member]
Derivative Assets	[8]	19,800,000		26,700,000
Derivative Liabilities	[8]	600,000		1,700,000
Risk Management Assets
Derivative Assets	[8]	19,800,000		26,700,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	600,000		1,700,000
Fair Value Hedges [Member]
Derivative Liabilities		98,400,000		127,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		98,400,000		127,400,000
Fair Value Hedges [Member] | Other [Member]
Derivative Liabilities		0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0		0
Fair Value Hedges [Member] | Level 1 [Member]
Derivative Liabilities		0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0		0
Fair Value Hedges [Member] | Level 2 [Member]
Derivative Liabilities		98,400,000		127,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		98,400,000		127,400,000
Fair Value Hedges [Member] | Level 3 [Member]
Derivative Liabilities		0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0		0
Interest Rate Foreign Currency Hedges [Member]
Derivative Assets				11,000,000.0
Derivative Liabilities		9,000,000.0
Risk Management Assets
Derivative Assets				11,000,000.0
Liabilities, Fair Value Disclosure
Derivative Liabilities		9,000,000.0
Interest Rate Foreign Currency Hedges [Member] | Other [Member]
Derivative Assets				0
Derivative Liabilities		0
Risk Management Assets
Derivative Assets				0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0
Interest Rate Foreign Currency Hedges [Member] | Level 1 [Member]
Derivative Assets				0
Derivative Liabilities		0
Risk Management Assets
Derivative Assets				0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0
Interest Rate Foreign Currency Hedges [Member] | Level 2 [Member]
Derivative Assets				11,000,000.0
Derivative Liabilities		9,000,000.0
Risk Management Assets
Derivative Assets				11,000,000.0
Liabilities, Fair Value Disclosure
Derivative Liabilities		9,000,000.0
Interest Rate Foreign Currency Hedges [Member] | Level 3 [Member]
Derivative Assets				0
Derivative Liabilities		0
Risk Management Assets
Derivative Assets				0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0
AEP Texas Inc. [Member]
Derivative Liabilities		2,700,000
Assets, Fair Value Disclosure
Cash and Cash Equivalents		34,000,000.0		32,700,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		2,700,000
AEP Texas Inc. [Member] | Other [Member]
Derivative Liabilities		(200,000)
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		(200,000)
AEP Texas Inc. [Member] | Level 1 [Member]
Derivative Liabilities		0
Assets, Fair Value Disclosure
Cash and Cash Equivalents		34,000,000.0		32,700,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		0
AEP Texas Inc. [Member] | Level 2 [Member]
Derivative Liabilities		2,900,000
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		2,900,000
AEP Texas Inc. [Member] | Level 3 [Member]
Derivative Liabilities		0
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member]
Derivative Liabilities	[8]	0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Derivative Liabilities	[8]	(200,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	(200,000)
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Derivative Liabilities	[8]	0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Derivative Liabilities	[8]	200,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	200,000
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Derivative Liabilities	[8]	0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	0
AEP Texas Inc. [Member] | Interest Rate Foreign Currency Hedges [Member]
Derivative Liabilities		2,700,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		2,700,000
AEP Texas Inc. [Member] | Interest Rate Foreign Currency Hedges [Member] | Other [Member]
Derivative Liabilities		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0
AEP Texas Inc. [Member] | Interest Rate Foreign Currency Hedges [Member] | Level 1 [Member]
Derivative Liabilities		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0
AEP Texas Inc. [Member] | Interest Rate Foreign Currency Hedges [Member] | Level 2 [Member]
Derivative Liabilities		2,700,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		2,700,000
AEP Texas Inc. [Member] | Interest Rate Foreign Currency Hedges [Member] | Level 3 [Member]
Derivative Liabilities		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0
Appalachian Power Co [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		14,900,000		14,400,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		37,300,000		83,500,000
Changes in the Fair Value of Net Trading Derivatives and Other Investments
Beginning Balance		69,100,000		41,700,000		19,300,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	(11,700,000)		3,000,000.0		8,300,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0		0
Settlements		(57,300,000)		(44,700,000)		(28,000,000.0)
Transfers into Level 3	[4],[5]	0		0		0
Transfers out of Level 3	[5]	0		0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	22,300,000		69,100,000		42,100,000
Ending Balance		22,400,000		69,100,000		41,700,000
Appalachian Power Co [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0		0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		(2,200,000)		(1,000,000.0)
Appalachian Power Co [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		14,900,000		14,400,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		14,900,000		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		1,100,000		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		23,500,000		69,400,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member]
Derivative Assets	[8]	22,400,000		69,100,000
Derivative Liabilities	[8]	22,500,000		3,500,000
Risk Management Assets
Derivative Assets	[8]	22,400,000		69,100,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	22,500,000		3,500,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Derivative Assets	[8]	(2,200,000)		(1,000,000.0)
Derivative Liabilities	[8]	(2,600,000)		(1,400,000)
Risk Management Assets
Derivative Assets	[8]	(2,200,000)		(1,000,000.0)
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	(2,600,000)		(1,400,000)
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Derivative Assets	[8]	0		0
Derivative Liabilities	[8]	0		0
Risk Management Assets
Derivative Assets	[8]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	0		0
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Derivative Assets	[8]	1,100,000		700,000
Derivative Liabilities	[8]	24,000,000.0		4,600,000
Risk Management Assets
Derivative Assets	[8]	1,100,000		700,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	24,000,000.0		4,600,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Derivative Assets	[8]	23,500,000		69,400,000
Derivative Liabilities	[8]	1,100,000		300,000
Risk Management Assets
Derivative Assets	[8]	23,500,000		69,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	1,100,000		300,000
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member]
Derivative Assets		23,500,000		69,400,000
Derivative Liabilities		1,100,000		300,000
Risk Management Assets
Derivative Assets		23,500,000		69,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		1,100,000		300,000
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(1.04)		(2.82)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(1.04)		(2.82)
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	6.45		18.88
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	6.45		18.88
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	1.36		3.89
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	1.36		3.89
Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,860,200,000		3,341,200,000
Total Assets		3,899,800,000		3,356,600,000
Changes in the Fair Value of Net Trading Derivatives and Other Investments
Beginning Balance		4,600,000		(700,000)		2,100,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	4,200,000		3,700,000		(100,000)
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0		0
Settlements		(8,800,000)		(3,000,000.0)		(2,200,000)
Transfers into Level 3	[4],[5]	0		0		0
Transfers out of Level 3	[5]	0		0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	2,800,000		4,600,000		(500,000)
Ending Balance		2,800,000		4,600,000		(700,000)
Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		9,000,000.0		9,900,000
Total Assets		6,700,000		8,700,000
Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,444,400,000		2,142,600,000
Total Assets		2,444,400,000		2,142,600,000
Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,406,800,000		1,188,700,000
Total Assets		1,444,200,000		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		4,500,000		5,300,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member]
Derivative Assets	[8]	39,600,000		15,400,000
Derivative Liabilities	[8]	2,000,000.0		0
Risk Management Assets
Derivative Assets	[8]	39,600,000		15,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	2,000,000.0		0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Derivative Assets	[8]	(2,300,000)		(1,200,000)
Derivative Liabilities	[8]	(3,400,000)		(1,300,000)
Risk Management Assets
Derivative Assets	[8]	(2,300,000)		(1,200,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	(3,400,000)		(1,300,000)
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Derivative Assets	[8]	0		0
Derivative Liabilities	[8]	0		0
Risk Management Assets
Derivative Assets	[8]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	0		0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Derivative Assets	[8]	37,400,000		11,300,000
Derivative Liabilities	[8]	3,700,000		600,000
Risk Management Assets
Derivative Assets	[8]	37,400,000		11,300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	3,700,000		600,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Derivative Assets	[8]	4,500,000		5,300,000
Derivative Liabilities	[8]	1,700,000		700,000
Risk Management Assets
Derivative Assets	[8]	4,500,000		5,300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	1,700,000		700,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member]
Derivative Assets		4,500,000		5,300,000
Derivative Liabilities		1,700,000		700,000
Risk Management Assets
Derivative Assets		4,500,000		5,300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		1,700,000		700,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(1.48)		0.16
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(1.48)		0.16
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	8.40		18.79
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	8.40		18.79
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.85		1.23
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.85		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)		(110,300,000)
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	(3,600,000)		6,500,000		2,400,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0		0
Settlements		5,600,000		300,000		6,300,000
Transfers into Level 3	[4],[5]	0		0		0
Transfers out of Level 3	[5]	0		0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	(12,600,000)		45,700,000		9,100,000
Ending Balance		(50,600,000)		(40,000,000.0)		(92,500,000)
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member]
Derivative Liabilities	[8]	50,700,000		39,700,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	50,700,000		39,700,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Derivative Liabilities	[8]	(100,000)		(300,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	(100,000)		(300,000)
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Derivative Liabilities	[8]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	0		0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Derivative Liabilities	[8]	200,000		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	200,000		0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Derivative Liabilities	[8]	50,600,000		40,000,000.0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	50,600,000		40,000,000.0
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Derivative Assets		0		0
Derivative Liabilities		50,600,000		40,000,000.0
Risk Management Assets
Derivative Assets		0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		50,600,000		40,000,000.0
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	22.92		2.91
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	22.92		2.91
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | High [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	67.53		187.34
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	67.53		187.34
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	42.85		48.76
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	42.85		48.76
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		10,300,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	29,800,000		24,200,000		16,100,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0		0
Settlements		(53,400,000)		(36,300,000)		(26,400,000)
Transfers into Level 3	[4],[5]	0		0		0
Transfers out of Level 3	[5]	0		0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	18,500,000		23,700,000		12,100,000
Ending Balance		18,600,000		23,700,000		12,100,000
Public Service Co Of Oklahoma [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets				(300,000)
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]
Derivative Assets	[8]	19,000,000.0		25,300,000
Derivative Liabilities	[8]	29,900,000		1,600,000
Risk Management Assets
Derivative Assets	[8]	19,000,000.0		25,300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	29,900,000		1,600,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Derivative Assets	[8]	(700,000)		1,300,000
Derivative Liabilities	[8]	(800,000)		(400,000)
Risk Management Assets
Derivative Assets	[8]	(700,000)		1,300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	(800,000)		(400,000)
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Derivative Assets	[8]	0		0
Derivative Liabilities	[8]	0		0
Risk Management Assets
Derivative Assets	[8]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	0		0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Derivative Assets	[8]	0		0
Derivative Liabilities	[8]	29,600,000		1,700,000
Risk Management Assets
Derivative Assets	[8]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	29,600,000		1,700,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Derivative Assets	[8]	19,700,000		24,000,000.0
Derivative Liabilities	[8]	1,100,000		300,000
Risk Management Assets
Derivative Assets	[8]	19,700,000		24,000,000.0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	1,100,000		300,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member]
Derivative Assets		19,700,000		24,000,000.0
Derivative Liabilities		1,100,000		300,000
Risk Management Assets
Derivative Assets		19,700,000		24,000,000.0
Liabilities, Fair Value Disclosure
Derivative Liabilities		1,100,000		300,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(25.45)		(36.45)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(25.45)		(36.45)
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	4.80		3.40
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	4.80		3.40
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(4.33)		(7.55)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(4.33)		(7.55)
Public Service Co Of Oklahoma [Member] | Interest Rate Foreign Currency Hedges [Member]
Derivative Assets				0
Risk Management Assets
Derivative Assets				0
Public Service Co Of Oklahoma [Member] | Interest Rate Foreign Currency Hedges [Member] | Other [Member]
Derivative Assets				(1,600,000)
Risk Management Assets
Derivative Assets				(1,600,000)
Public Service Co Of Oklahoma [Member] | Interest Rate Foreign Currency Hedges [Member] | Level 1 [Member]
Derivative Assets				0
Risk Management Assets
Derivative Assets				0
Public Service Co Of Oklahoma [Member] | Interest Rate Foreign Currency Hedges [Member] | Level 2 [Member]
Derivative Assets				1,600,000
Risk Management Assets
Derivative Assets				1,600,000
Public Service Co Of Oklahoma [Member] | Interest Rate Foreign Currency Hedges [Member] | Level 3 [Member]
Derivative Assets				0
Risk Management Assets
Derivative 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		1,600,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	20,000,000.0		35,800,000		9,500,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0		0
Settlements		(34,200,000)		(45,000,000.0)		(15,500,000)
Transfers into Level 3	[4],[5]	0		0		0
Transfers out of Level 3	[5]	0		6,900,000		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	11,100,000		5,600,000		15,300,000
Ending Balance		11,100,000		14,200,000		$ 10,900,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member]
Derivative Assets	[8]	11,600,000		16,400,000
Derivative Liabilities	[8]	15,600,000		1,400,000
Risk Management Assets
Derivative Assets	[8]	11,600,000		16,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	15,600,000		1,400,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Derivative Assets	[8]	(900,000)		(400,000)
Derivative Liabilities	[8]	(1,000,000.0)		(600,000)
Risk Management Assets
Derivative Assets	[8]	(900,000)		(400,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	(1,000,000.0)		(600,000)
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Derivative Assets	[8]	0		0
Derivative Liabilities	[8]	0		0
Risk Management Assets
Derivative Assets	[8]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	0		0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Derivative Assets	[8]	500,000		2,200,000
Derivative Liabilities	[8]	15,700,000		1,600,000
Risk Management Assets
Derivative Assets	[8]	500,000		2,200,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	15,700,000		1,600,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Derivative Assets	[8]	12,000,000.0		14,600,000
Derivative Liabilities	[8]	900,000		400,000
Risk Management Assets
Derivative Assets	[8]	12,000,000.0		14,600,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[8]	900,000		400,000
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Level 3 [Member]
Derivative Assets		0
Derivative Liabilities		500,000
Risk Management Assets
Derivative Assets		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		500,000
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Level 3 [Member] | Low [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] | Level 3 [Member] | High [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] | Level 3 [Member] | Weighted Average [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] | FTRs [Member] | Level 3 [Member]
Derivative Assets		12,000,000.0		14,600,000
Derivative Liabilities		400,000		400,000
Risk Management Assets
Derivative Assets		12,000,000.0		14,600,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		400,000		400,000
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(25.45)		(36.45)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(25.45)		(36.45)
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	4.80		3.40
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	4.80		3.40
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(4.33)		(7.55)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(4.33)		(7.55)
Cash [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		48,900,000		47,100,000
Other Temporary Investments	[13]	48,900,000		47,100,000
Cash [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0		0
Cash [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		48,900,000		47,100,000
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]
Assets, Fair Value Disclosure
Other Temporary Investments		13,900,000		9,000,000.0
Other Cash Deposits [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Temporary Investments	[14]	13,900,000		9,000,000.0
Other Cash Deposits [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments		0		0
Other Cash Deposits [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments		0		0
Other Cash Deposits [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments		0		0
Mutual Funds Fixed Income [Member]
Assets, Fair Value Disclosure
Other Temporary Investments	[15]	159,700,000		144,100,000
Mutual Funds Fixed Income [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Temporary Investments		0		0
Mutual Funds Fixed Income [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments		159,700,000		144,100,000
Mutual Funds Fixed Income [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments		0		0
Mutual Funds Fixed Income [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments		0		0
Mutual Funds Equity [Member]
Assets, Fair Value Disclosure
Other Temporary Investments	[16]	40,700,000		34,500,000
Mutual Funds Equity [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Temporary Investments	[16]	0		0
Mutual Funds Equity [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments	[16]	40,700,000		34,500,000
Mutual Funds Equity [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments	[16]	0		0
Mutual Funds Equity [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments	[16]	0		0
Cash and Cash Equivalents [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	16,800,000		21,200,000
Cash and Cash Equivalents [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	9,000,000.0		9,900,000
Cash and Cash Equivalents [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	7,800,000		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]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	16,800,000		21,200,000
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]	9,000,000.0		9,900,000
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]	7,800,000		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]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,273,000,000		1,123,800,000
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] | 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		1,273,000,000		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]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,273,000,000		1,123,800,000
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] | 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		1,273,000,000		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 Securities [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		132,100,000		61,600,000
Corporate Debt Securities [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0		0
Corporate Debt Securities [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0		0
Corporate Debt Securities [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		132,100,000		61,600,000
Corporate Debt Securities [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0		0
Corporate Debt Securities [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		132,100,000		61,600,000
Corporate Debt Securities [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0		0
Corporate 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
Corporate Debt Securities [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		132,100,000		61,600,000
Corporate 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
State and Local Jurisdiction
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,700,000		3,300,000
State and Local Jurisdiction | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0		0
State and Local Jurisdiction | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0		0
State and Local Jurisdiction | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,700,000		3,300,000
State and Local Jurisdiction | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0		0
State and Local Jurisdiction | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,700,000		3,300,000
State and Local Jurisdiction | 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 | 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 | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,700,000		3,300,000
State and Local Jurisdiction | 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]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,406,800,000		1,188,700,000
Fixed Income Funds [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0		0
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		1,406,800,000		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]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,406,800,000		1,188,700,000
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] | 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		1,406,800,000		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]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,436,600,000		2,131,300,000
Domestic [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	0		0
Domestic [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,436,600,000		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]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,436,600,000		2,131,300,000
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] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,436,600,000		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] 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 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.

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

[10] Represents market prices in dollars per MWh.

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

[12] Represents market prices in dollars per MMBtu.

[13] 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.