Fair Value Financial Assets Liabilities (Details) - USD ($)		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Assets, Fair Value Disclosure
Other Temporary Investments		$ 268,400,000		$ 246,400,000
Risk Management Assets
Derivative Assets		461,400,000		336,900,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,867,000,000		3,306,700,000
Total Assets		4,640,500,000		3,921,800,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		305,700,000		311,600,000
Changes in the Fair Value of Net Trading Derivatives and Other Investments
Beginning Balance		113,300,000		109,900,000		$ 131,200,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	48,600,000		39,500,000		15,800,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	(45,200,000)		35,300,000		(100,000)
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	24,200,000		13,800,000		(15,100,000)
Settlements		(89,000,000.0)		(113,100,000)		(117,600,000)
Transfers into Level 3	[4],[5]	(3,800,000)		(3,800,000)		(600,000)
Transfers out of Level 3	[5]	(34,400,000)		5,600,000		35,600,000
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	89,400,000		26,100,000		60,700,000
Assets and Liabilities Held for Sale related to KPCo	[7],[8]	(5,800,000)
Ending Balance		97,300,000		113,300,000		109,900,000
Fair Value Measurements 1 (Textuals)
Assets Held for Sale		2,919,700,000		0
Liabilities Held for Sale		1,880,900,000		0
Held For Sale [Member]
Fair Value Measurements 1 (Textuals)
Assets Held for Sale		6,400,000
Liabilities Held for Sale		600,000
Other [Member]
Assets, Fair Value Disclosure
Other Temporary Investments		10,000,000.0		10,500,000
Risk Management Assets
Derivative Assets		(684,100,000)		(218,500,000)
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		7,000,000.0		9,000,000.0
Total Assets		(667,100,000)		(199,000,000.0)
Liabilities, Fair Value Disclosure
Derivative Liabilities		(424,900,000)		(221,900,000)
Level 1 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments		258,400,000		235,900,000
Risk Management Assets
Derivative Assets		7,400,000		900,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,619,600,000		2,071,500,000
Total Assets		2,914,200,000		2,308,300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		5,300,000		900,000
Level 2 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments		0		0
Risk Management Assets
Derivative Assets		892,600,000		298,200,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,240,400,000		1,226,200,000
Total Assets		2,147,900,000		1,524,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		577,100,000		357,800,000
Level 3 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments		0		0
Risk Management Assets
Derivative Assets		245,500,000		256,300,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0		0
Total Assets		245,500,000		288,100,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		148,200,000		174,800,000
2021 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities				47,000,000
2022 [Member] | Level 1 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		1,000,000
2022 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		42,000,000
2022 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		82,000,000
2022 - 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				3,000,000
2022 - 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				37,000,000
2023 - 2025 [Member] | Level 1 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		1,000,000
2023 - 2025 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		109,000,000
2023 - 2025 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		10,000,000
2025 - 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				11,000,000
2025 - 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				14,000,000
2026-2027 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		10,000,000
2026-2027 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity Of Net Fair Value Of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		9,000,000
2027 - 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
2027 - 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				(13,000,000)
2028 - 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		3,000,000
2028 - 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		(17,000,000)
Risk Management Commodity Contracts [Member]
Risk Management Assets
Derivative Assets	[10]	239,800,000	[9],[11]	322,100,000	[12]
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10]	254,700,000	[11],[13]	218,900,000	[12]
Fair Value Measurements 1 (Textuals)
Assets Held for Sale		6,000,000
Liabilities Held for Sale		100,000
Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Derivative Assets	[10]	(642,400,000)	[9],[11]	(190,000,000.0)	[12]
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10]	(383,200,000)	[11],[13]	(193,400,000)	[12]
Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Derivative Assets	[10]	7,400,000	[9],[11]	900,000	[12]
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10]	5,300,000	[11],[13]	900,000	[12]
Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Derivative Assets	[10]	648,500,000	[9],[11]	258,800,000	[12]
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10]	485,000,000.0	[11],[13]	244,200,000	[12]
Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets	[10]	226,300,000	[9],[11]	252,400,000	[12]
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10]	147,600,000	[11],[13]	167,200,000	[12]
Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		164,400,000		213,500,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		135,200,000	[14]	169,700,000
Fair Value Measurements 1 (Textuals)
Liabilities Held for Sale		100,000
Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	10.30		5.33
Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	76.70		100.47
Energy Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15],[16]	37.11		32.73
Natural Gas Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		3,600,000		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0		1,700,000
Natural Gas Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[17]	3.11		2.18
Natural Gas Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[17]	4.02		2.77
Natural Gas Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[16],[17]	3.47		2.40
FTRs [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		77,500,000	[18]	42,800,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		13,000,000.0	[19]	3,400,000
Fair Value Measurements 1 (Textuals)
Assets Held for Sale		6,000,000
Liabilities Held for Sale		500,000
FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	(23.93)		(15.08)
FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	26.38		9.66
FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15],[16]	0.86		0.19
Commodity Hedges [Member]
Risk Management Assets
Derivative Assets	[10]	220,400,000		9,800,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10]	12,900,000		85,200,000
Commodity Hedges [Member] | Other [Member]
Risk Management Assets
Derivative Assets	[10]	(41,700,000)		(28,500,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10]	(41,700,000)		(28,500,000)
Commodity Hedges [Member] | Level 1 [Member]
Risk Management Assets
Derivative Assets	[10]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10]	0		0
Commodity Hedges [Member] | Level 2 [Member]
Risk Management Assets
Derivative Assets	[10]	242,900,000		34,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10]	54,000,000.0		106,100,000
Commodity Hedges [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets	[10]	19,200,000		3,900,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10]	600,000		7,600,000
Interest Rate Foreign Currency Hedges [Member]
Risk Management Assets
Derivative Assets				2,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities				3,400,000
Interest Rate Foreign Currency Hedges [Member] | Other [Member]
Risk Management Assets
Derivative Assets				0
Liabilities, Fair Value Disclosure
Derivative Liabilities				0
Interest Rate Foreign Currency Hedges [Member] | Level 1 [Member]
Risk Management Assets
Derivative Assets				0
Liabilities, Fair Value Disclosure
Derivative Liabilities				0
Interest Rate Foreign Currency Hedges [Member] | Level 2 [Member]
Risk Management Assets
Derivative Assets				2,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities				3,400,000
Interest Rate Foreign Currency Hedges [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets				0
Liabilities, Fair Value Disclosure
Derivative Liabilities				0
Fair Value Hedges [Member]
Risk Management Assets
Derivative Assets		1,200,000		2,600,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		38,100,000		4,100,000
Fair Value Hedges [Member] | Other [Member]
Risk Management Assets
Derivative Assets		0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0		0
Fair Value Hedges [Member] | Level 1 [Member]
Risk Management Assets
Derivative Assets		0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0		0
Fair Value Hedges [Member] | Level 2 [Member]
Risk Management Assets
Derivative Assets		1,200,000		2,600,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		38,100,000		4,100,000
Fair Value Hedges [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0		0
Other Investments [Member]
Risk Management Assets
Derivative Assets		43,700,000	[20]	31,800,000
Other Investments [Member] | Other [Member]
Risk Management Assets
Derivative Assets		0	[20]	0
Other Investments [Member] | Level 1 [Member]
Risk Management Assets
Derivative Assets		28,800,000	[20]	0
Other Investments [Member] | Level 2 [Member]
Risk Management Assets
Derivative Assets		14,900,000	[20]	0
Other Investments [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		0	[20]	31,800,000
Liabilities, Fair Value Disclosure
Derivative Liabilities				0
Other Investments [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit				0.10
Other Investments [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit				0.20
Other Investments [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit				0.15
AEP Texas Inc. [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		30,400,000		28,700,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		30,400,000		28,700,000
AEP Texas Inc. [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0		0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		(600,000)		(400,000)
AEP Texas Inc. [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		30,400,000		28,700,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		30,400,000		28,700,000
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		600,000		400,000
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		0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Derivative Assets		0	[10]	0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Derivative Assets		(600,000)	[10]	(400,000)
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Derivative Assets		0	[10]	0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Derivative Assets		600,000	[10]	400,000
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		0	[10]	0
AEP Transmission Co [Member]
Fair Value Measurements 1 (Textuals)
Assets Held for Sale		167,900,000		0
Liabilities Held for Sale		27,600,000		0
Appalachian Power Co [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		17,600,000		16,900,000
Risk Management Assets
Derivative Assets				22,500,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		59,600,000		39,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities				4,700,000
Changes in the Fair Value of Net Trading Derivatives and Other Investments
Beginning Balance		19,300,000		37,700,000		57,800,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	8,300,000		13,200,000		(13,900,000)
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0		0
Settlements		(28,000,000.0)		(51,600,000)		(42,500,000)
Transfers into Level 3	[4],[5]	0		0		(500,000)
Transfers out of Level 3	[5]	0		700,000		(700,000)
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	42,100,000		19,300,000		37,500,000
Assets and Liabilities Held for Sale related to KPCo		0
Ending Balance		41,700,000		19,300,000		37,700,000
Appalachian Power Co [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0		0
Risk Management Assets
Derivative Assets				(19,200,000)
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		(5,800,000)		(19,200,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities				(18,800,000)
Appalachian Power Co [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		17,600,000		16,900,000
Risk Management Assets
Derivative Assets				0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		17,600,000		16,900,000
Liabilities, Fair Value Disclosure
Derivative Liabilities				0
Appalachian Power Co [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0		0
Risk Management Assets
Derivative Assets				21,800,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		5,800,000		21,800,000
Liabilities, Fair Value Disclosure
Derivative Liabilities				22,900,000
Appalachian Power Co [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0		0
Risk Management Assets
Derivative Assets		42,000,000.0		19,900,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		42,000,000.0		19,900,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		300,000		600,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Derivative Assets	[10],[21]	42,000,000.0		20,100,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	800,000		1,300,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Derivative Assets	[10],[21]	(5,800,000)		(19,200,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	(6,700,000)		(18,800,000)
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	0		0
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	5,800,000		19,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	7,200,000		19,500,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	42,000,000.0		19,900,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	300,000		600,000
Appalachian Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		0		1,000,000.0
Liabilities, Fair Value Disclosure
Derivative Liabilities		300,000		600,000
Appalachian Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	32.20		10.84
Appalachian Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	56.54		41.09
Appalachian Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15],[16]	44.77		25.08
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		42,000,000.0		18,900,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		0		0
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	(0.30)		0.04
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	26.38		5.61
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15],[16]	2.63		1.13
Appalachian Power Co [Member] | Interest Rate Foreign Currency Hedges [Member]
Risk Management Assets
Derivative Assets				2,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities				3,400,000
Appalachian Power Co [Member] | Interest Rate Foreign Currency Hedges [Member] | Other [Member]
Risk Management Assets
Derivative Assets				0
Liabilities, Fair Value Disclosure
Derivative Liabilities				0
Appalachian Power Co [Member] | Interest Rate Foreign Currency Hedges [Member] | Level 1 [Member]
Risk Management Assets
Derivative Assets				0
Liabilities, Fair Value Disclosure
Derivative Liabilities				0
Appalachian Power Co [Member] | Interest Rate Foreign Currency Hedges [Member] | Level 2 [Member]
Risk Management Assets
Derivative Assets				2,400,000
Liabilities, Fair Value Disclosure
Derivative Liabilities				3,400,000
Appalachian Power Co [Member] | Interest Rate Foreign Currency Hedges [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets				0
Liabilities, Fair Value Disclosure
Derivative Liabilities				0
Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,867,000,000		3,306,700,000
Total Assets		3,870,300,000		3,310,400,000
Changes in the Fair Value of Net Trading Derivatives and Other Investments
Beginning Balance		2,100,000		5,800,000		8,900,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	(100,000)		2,500,000		4,700,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0		0
Settlements		(2,200,000)		(8,600,000)		(13,000,000.0)
Transfers into Level 3	[4],[5]	0		0		(300,000)
Transfers out of Level 3	[5]	0		400,000		(400,000)
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	(500,000)		2,000,000.0		5,900,000
Assets and Liabilities Held for Sale related to KPCo		0
Ending Balance		(700,000)		2,100,000		5,800,000
Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		7,000,000.0		9,000,000.0
Total Assets		(1,100,000)		(4,900,000)
Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,619,600,000		2,071,500,000
Total Assets		2,619,600,000		2,071,500,000
Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,240,400,000		1,226,200,000
Total Assets		1,244,200,000		1,241,300,000
Indiana Michigan Power Co [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		7,600,000		2,500,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0		0
Total Assets		7,600,000		2,500,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		8,300,000		400,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Derivative Assets	[10],[21]	3,300,000		3,700,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	5,000,000.0		200,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Derivative Assets	[10],[21]	(8,100,000)		(13,900,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	(10,000,000.0)		(12,200,000)
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	0		0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	3,800,000		15,100,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	6,700,000		12,000,000.0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	7,600,000		2,500,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	8,300,000		400,000
Indiana Michigan Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		0		600,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		200,000		300,000
Indiana Michigan Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	32.20		10.84
Indiana Michigan Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	56.54		41.09
Indiana Michigan Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15],[16]	44.77		25.08
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		7,600,000		1,900,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		8,100,000		100,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	(5.45)		(1.96)
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	17.78		3.69
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	[15],[16]	(0.12)		0.33
Ohio Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and Other Investments
Beginning Balance		(110,300,000)		(103,600,000)		(99,400,000)
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	2,400,000		(1,600,000)		(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		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0		0
Settlements		6,300,000		8,900,000		6,600,000
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]	9,100,000		(14,000,000.0)		(9,900,000)
Assets and Liabilities Held for Sale related to KPCo		0
Ending Balance		(92,500,000)		(110,300,000)		(103,600,000)
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Derivative Assets	[10],[21]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	92,500,000		110,300,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Derivative Assets	[10],[21]	(500,000)		(300,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	0		0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	0		0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	500,000		300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	0		0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	92,500,000		110,300,000
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		92,500,000		110,300,000
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	14.26		16.19
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	52.98		46.98
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	[15],[16]	30.68		28.30
Public Service Co Of Oklahoma [Member]
Changes in the Fair Value of Net Trading Derivatives and Other Investments
Beginning Balance		10,300,000		15,800,000		9,500,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	16,100,000		11,900,000		13,500,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0		0
Settlements		(26,400,000)		(27,600,000)		(23,000,000.0)
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]	12,100,000		10,200,000		15,800,000
Assets and Liabilities Held for Sale related to KPCo		0
Ending Balance		12,100,000		10,300,000		15,800,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Derivative Assets	[10],[21]	12,100,000		10,300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	3,700,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Derivative Assets	[10],[21]	(400,000)		(200,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	(100,000)
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	300,000		200,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	3,700,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	12,200,000		10,300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	100,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		12,200,000		10,300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		100,000		0
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	[15]	(18.39)		(6.93)
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	[15]	1.87		0.48
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	[15],[16]	(2.57)		(1.93)
Southwestern Electric Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and Other Investments
Beginning Balance		1,600,000		1,400,000		2,300,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	9,500,000		2,800,000		6,000,000.0
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0		0
Settlements		(15,500,000)		(6,600,000)		(9,600,000)
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]	15,300,000		4,000,000.0		2,700,000
Assets and Liabilities Held for Sale related to KPCo		0
Ending Balance		10,900,000		1,600,000		$ 1,400,000
Southwestern Electric Power Co [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		11,000,000.0		3,300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		100,000		1,700,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Derivative Assets	[10],[21]	10,900,000		3,200,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	2,100,000		1,700,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Derivative Assets	[10],[21]	(400,000)		(200,000)
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	(100,000)		0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	0		0
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	0		0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	300,000		100,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	2,100,000		0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets	[10],[21]	11,000,000.0		3,300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities	[10],[21]	100,000		1,700,000
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		3,600,000		0
Liabilities, Fair Value Disclosure
Derivative Liabilities		0		1,700,000
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[17]	3.11		2.18
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[17]	4.02		2.77
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[16],[17]	3.47		2.41
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Derivative Assets		7,400,000		3,300,000
Liabilities, Fair Value Disclosure
Derivative Liabilities		100,000		0
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	(18.39)		(6.93)
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[15]	1.87		0.48
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	[15],[16]	(2.57)		(1.93)
Cash [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		48,000,000.0		45,600,000
Other Temporary Investments	[22]	48,000,000.0		45,600,000
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		48,000,000.0		45,600,000
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	[23]	10,000,000.0		22,700,000
Other Cash Deposits [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Temporary Investments	[23]	10,000,000.0		10,500,000
Other Cash Deposits [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments		0		12,200,000
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	[24]	154,800,000		123,500,000
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		154,800,000		123,500,000
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	[25]	55,600,000		54,600,000
Mutual Funds Equity [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Temporary Investments	[25]	0		0
Mutual Funds Equity [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments	[25]	55,600,000		54,600,000
Mutual Funds Equity [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments	[25]	0		0
Mutual Funds Equity [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Temporary Investments	[25]	0		0
Cash and Cash Equivalents [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[26]	84,700,000		25,800,000
Cash and Cash Equivalents [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[26]	7,000,000.0		9,000,000.0
Cash and Cash Equivalents [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[26]	77,700,000		16,800,000
Cash and Cash Equivalents [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[26]	0		0
Cash and Cash Equivalents [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[26]	0		0
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[26]	84,700,000		25,800,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[26]	7,000,000.0		9,000,000.0
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	[26]	77,700,000		16,800,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[26]	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	[26]	0		0
US Government Agencies Debt Securities [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,156,400,000		1,025,600,000
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		1,156,400,000		1,025,600,000
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		1,156,400,000		1,025,600,000
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		1,156,400,000		1,025,600,000
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		76,700,000		86,300,000
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		76,700,000		86,300,000
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		76,700,000		86,300,000
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		76,700,000		86,300,000
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		7,300,000		114,300,000
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		7,300,000		114,300,000
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		7,300,000		114,300,000
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		7,300,000		114,300,000
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		1,240,400,000		1,226,200,000
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		1,240,400,000		1,226,200,000
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		1,240,400,000		1,226,200,000
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		1,240,400,000		1,226,200,000
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	[25]	2,541,900,000		2,054,700,000
Domestic [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[25]	0		0
Domestic [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[25]	2,541,900,000		2,054,700,000
Domestic [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[25]	0		0
Domestic [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[25]	0		0
Domestic [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[25]	2,541,900,000		2,054,700,000
Domestic [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[25]	0		0
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[25]	2,541,900,000		2,054,700,000
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[25]	0		0
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[25]	$ 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] Amount excludes Risk Management Assets of $6.4 million classified as Assets Held for Sale on the balance sheets. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[8] Amount excludes Risk Management Liabilities of $0.6 million classified as Liabilities Held for Sale on the balance sheets. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[9] Amount excludes Risk Management Assets of $6 million classified as Assets Held for Sale on the balance sheets. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[10] 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.”

[11] The December 31, 2021 maturities of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), were as follows: Level 1 matures $1 million in 2022 and $1 million in periods 2023-2025; Level 2 matures $42 million in 2022, $109 million in periods 2023-2025, $10 million in periods 2026-2027 and $3 million in periods 2028-2033; Level 3 matures $82 million in 2022, $10 million in periods 2023-2025, $9 million in periods 2026-2027 and $(17) million in periods 2028-2033. Risk management commodity contracts are substantially comprised of power contracts.

[12] The December 31, 2020 maturities of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), were as follows: Level 2 matures $3 million in periods 2022-2024, $11 million in periods 2025-2026 and $1 million in periods 2027-2033; Level 3 matures $47 million in 2021, $37 million in periods 2022-2024, $14 million in periods 2025-2026 and $(13) million in periods 2027-2033.  Risk management commodity contracts are substantially comprised of power contracts.

[13] Amount excludes Risk Management Liabilities of $0.1 million classified as Liabilities Held for Sale on the balance sheets. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[14] Amount excludes Risk Management Liabilities of $0.1 million classified as Liabilities Held for Sale on the balance sheets. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[15] Represents market prices in dollars per MWh.

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

[17] Represents market prices in dollars per MMBtu.

[18] Amount excludes Risk Management Assets of $6 million classified as Assets Held for Sale on the balance sheets. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[19] Amount excludes Risk Management Liabilities of $0.5 million classified as Liabilities Held for Sale on the balance sheets. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[20] See “Warrants Held in Investee” section of Note 10 for additional information.

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

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

[23] 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.

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

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

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