Fair Value Assets and Liabilities (Details) - USD ($)		3 Months Ended			9 Months Ended
		Sep. 30, 2020		Sep. 30, 2019	Sep. 30, 2020		Sep. 30, 2019	Dec. 31, 2019
Assets, Fair Value Disclosure
Other Short-term Investments		$ 263,100,000			$ 263,100,000			$ 388,500,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,075,900,000			3,075,900,000			2,975,700,000
Total Assets		3,697,100,000			3,697,100,000			3,803,600,000
Risk Management Assets
Risk Management Assets		358,100,000			358,100,000			439,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		294,800,000			294,800,000			376,100,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		111,600,000		$ 112,700,000	109,900,000		$ 131,200,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	18,700,000		30,200,000	39,600,000		14,600,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	6,500,000		2,900,000	(2,400,000)		32,900,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	[3]	2,600,000		22,100,000	21,700,000		(42,800,000)
Settlements		(37,000,000.0)		(67,400,000)	(115,300,000)		(114,600,000)
Transfers into Level 3	[4],[5]	(1,000,000.0)		3,500,000	(1,100,000)		400,000
Transfers out of Level 3	[5]	1,100,000		6,600,000	5,600,000		1,400,000
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	3,600,000		(300,000)	48,100,000		87,200,000
Ending Balance		106,100,000		110,300,000	106,100,000		110,300,000
Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		13,300,000			13,300,000			17,100,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		9,000,000.0			9,000,000.0			8,600,000
Total Assets		(191,200,000)			(191,200,000)			(385,500,000)
Risk Management Assets
Risk Management Assets		(213,500,000)			(213,500,000)			(411,200,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(222,200,000)			(222,200,000)			(445,500,000)
Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		249,800,000			249,800,000			371,400,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,818,200,000			1,818,200,000			1,774,600,000
Total Assets		2,071,200,000			2,071,200,000			2,150,000,000.0
Risk Management Assets
Risk Management Assets		3,200,000			3,200,000			4,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		3,400,000			3,400,000			3,800,000
Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,248,700,000			1,248,700,000			1,192,500,000
Total Assets		1,532,500,000			1,532,500,000			1,666,700,000
Risk Management Assets
Risk Management Assets		283,800,000			283,800,000			474,200,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		335,100,000			335,100,000			555,300,000
Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Total Assets		284,600,000			284,600,000			372,400,000
Risk Management Assets
Risk Management Assets		284,600,000			284,600,000			372,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		178,500,000			178,500,000			262,500,000
2020 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(6,000,000)			(6,000,000)			(7,000,000)
2020 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		35,000,000			35,000,000			96,000,000
2021 - 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		3,000,000			3,000,000			(3,000,000)
2021 - 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		63,000,000			63,000,000			36,000,000
2024 - 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		4,000,000			4,000,000
2024 - 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		21,000,000			21,000,000			25,000,000
2026 - 2032 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities								(12,000,000)
2026-2033 [Memeber] | 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			7,000,000
2026-2033 [Memeber] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(12,000,000)			(12,000,000)
Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7]	345,300,000	[8]		345,300,000	[8]		408,800,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	221,700,000	[8]		221,700,000	[8]		239,000,000.0	[9]
Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7]	(185,300,000)	[8]		(185,300,000)	[8]		(404,500,000)	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	(194,000,000.0)	[8]		(194,000,000.0)	[8]		(438,800,000)	[9]
Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7]	3,200,000	[8]		3,200,000	[8]		4,000,000.0	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	3,400,000	[8]		3,400,000	[8]		3,800,000	[9]
Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7]	247,100,000	[8]		247,100,000	[8]		440,100,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	239,100,000	[8]		239,100,000	[8]		450,000,000.0	[9]
Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7]	280,300,000	[8]		280,300,000	[8]		369,200,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	173,200,000	[8]		173,200,000	[8]		224,000,000.0	[9]
Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		219,200,000			219,200,000			296,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		173,000,000.0			173,000,000.0			249,300,000
Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	3.36			3.36			(0.05)
Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	111.42			111.42			177.30
Energy Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	32.62			32.62			31.31
Natural Gas Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		600,000			600,000			4,900,000
Natural Gas Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]	1.79			1.79			1.89
Natural Gas Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]	3.06			3.06			2.51
Natural Gas Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[11],[12]	2.61			2.61			2.19
FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		65,400,000			65,400,000			75,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		4,900,000			4,900,000			8,300,000
FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(6.15)			(6.15)			(8.52)
FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	10.66			10.66			9.34
FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.23			0.23			0.42
Commodity Hedges [Member]
Risk Management Assets
Risk Management Assets	[7]	12,200,000			12,200,000			11,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	67,800,000			67,800,000			137,100,000
Commodity Hedges [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7]	(28,200,000)			(28,200,000)			(6,700,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	(28,200,000)			(28,200,000)			(6,700,000)
Commodity Hedges [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	0			0			0
Commodity Hedges [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7]	36,100,000			36,100,000			15,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	90,700,000			90,700,000			105,300,000
Commodity Hedges [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7]	4,300,000			4,300,000			3,200,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	5,300,000			5,300,000			38,500,000
Interest Rate [Member]
Risk Management Assets
Risk Management Assets		600,000			600,000			4,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		5,300,000			5,300,000
Interest Rate [Member] | Other [Member]
Risk Management Assets
Risk Management Assets		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Interest Rate [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Interest Rate [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets		600,000			600,000			4,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		5,300,000			5,300,000
Interest Rate [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Fair Value Hedges [Member]
Risk Management Assets
Risk Management Assets								14,500,000
Fair Value Hedges [Member] | Other [Member]
Risk Management Assets
Risk Management Assets								0
Fair Value Hedges [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets								0
Fair Value Hedges [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets								14,500,000
Fair Value Hedges [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets								0
AEP Texas Inc. [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		44,800,000			44,800,000			154,700,000
AEP Texas Inc. [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
AEP Texas Inc. [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		44,800,000			44,800,000			154,700,000
AEP Texas Inc. [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
AEP Texas Inc. [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	100,000			100,000
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	(100,000)			(100,000)
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	0			0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	200,000			200,000
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	0			0
Appalachian Power Co [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		9,300,000			9,300,000			23,500,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		40,100,000			40,100,000			63,000,000.0
Risk Management Assets
Risk Management Assets		30,800,000			30,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		5,800,000			5,800,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		36,500,000		68,500,000	37,700,000		57,800,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	6,400,000		13,800,000	13,100,000		(14,100,000)
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0	0		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	[3]	0		0	0		0
Settlements		(11,100,000)		(28,100,000)	(51,400,000)		(41,900,000)
Transfers into Level 3	[4],[5]	0		0	0		0
Transfers out of Level 3	[5]	0		0	700,000		(700,000)
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	(2,200,000)		1,300,000	29,500,000		54,400,000
Ending Balance		29,600,000		55,500,000	29,600,000		55,500,000
Appalachian Power Co [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		(20,300,000)			(20,300,000)			(85,600,000)
Risk Management Assets
Risk Management Assets		(20,300,000)			(20,300,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(21,200,000)			(21,200,000)
Appalachian Power Co [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		9,300,000			9,300,000			23,500,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		9,300,000			9,300,000			23,500,000
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Appalachian Power Co [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		21,000,000.0			21,000,000.0			84,600,000
Risk Management Assets
Risk Management Assets		21,000,000.0			21,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		26,500,000			26,500,000
Appalachian Power Co [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		30,100,000			30,100,000			40,500,000
Risk Management Assets
Risk Management Assets		30,100,000			30,100,000			40,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		500,000			500,000			2,800,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	30,200,000			30,200,000			39,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	500,000			500,000			1,900,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	(20,300,000)			(20,300,000)			(85,600,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	(21,200,000)			(21,200,000)			(84,900,000)
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	0			0			0
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	20,400,000			20,400,000			84,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	21,200,000			21,200,000			84,000,000.0
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	30,100,000			30,100,000			40,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	500,000			500,000			2,800,000
Appalachian Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		800,000			800,000			5,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		500,000			500,000			2,600,000
Appalachian Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	9.56			9.56			12.70
Appalachian Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	41.80			41.80			41.20
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	[10],[11]	27.25			27.25			25.92
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		29,300,000			29,300,000			34,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			200,000
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(0.81)			(0.81)			(0.14)
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	6.57			6.57			7.08
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	1.09			1.09			1.70
Appalachian Power Co [Member] | Interest Rate [Member]
Risk Management Assets
Risk Management Assets		600,000			600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		5,300,000			5,300,000
Appalachian Power Co [Member] | Interest Rate [Member] | Other [Member]
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Appalachian Power Co [Member] | Interest Rate [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Appalachian Power Co [Member] | Interest Rate [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets		600,000			600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		5,300,000			5,300,000
Appalachian Power Co [Member] | Interest Rate [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		3,075,900,000			3,075,900,000			2,975,700,000
Total Assets		3,080,000,000.0			3,080,000,000.0			2,985,600,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		4,500,000		12,300,000	5,800,000		8,900,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	3,300,000		3,100,000	2,400,000		4,600,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0	0		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	[3]	0		0	0		0
Settlements		(5,000,000.0)		(7,200,000)	(8,500,000)		(12,600,000)
Transfers into Level 3	[4],[5]	0		0	0		0
Transfers out of Level 3	[5]	0		0	400,000		(400,000)
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	1,000,000.0		700,000	3,700,000		8,400,000
Ending Balance		3,800,000		8,900,000	3,800,000		8,900,000
Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		9,000,000.0			9,000,000.0			8,600,000
Total Assets		(3,900,000)			(3,900,000)			(49,000,000.0)
Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,818,200,000			1,818,200,000			1,774,600,000
Total Assets		1,818,200,000			1,818,200,000			1,774,600,000
Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,248,700,000			1,248,700,000			1,192,500,000
Total Assets		1,261,600,000			1,261,600,000			1,252,000,000.0
Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Total Assets		4,100,000			4,100,000			8,000,000.0
Risk Management Assets
Risk Management Assets		4,100,000			4,100,000			8,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		300,000			300,000			2,200,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	4,100,000			4,100,000			9,900,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	300,000			300,000			500,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	(12,900,000)			(12,900,000)			(57,600,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	(13,400,000)			(13,400,000)			(55,100,000)
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	0			0			0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	12,900,000			12,900,000			59,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	13,400,000			13,400,000			53,400,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	4,100,000			4,100,000			8,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	300,000			300,000			2,200,000
Indiana Michigan Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		500,000			500,000			3,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		300,000			300,000			1,500,000
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	[10]	9.56			9.56			12.70
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	[10]	41.80			41.80			41.20
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	[10],[11]	27.25			27.25			25.92
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		3,600,000			3,600,000			4,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			700,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(2.68)			(2.68)			(0.75)
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	4.24			4.24			4.07
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.41			0.41			0.74
Ohio Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		(117,400,000)		(111,500,000)	(103,600,000)		(99,400,000)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	0		0	(1,200,000)		(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		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	[3]	0		0	0		0
Settlements		1,300,000		1,100,000	6,400,000		4,600,000
Transfers into Level 3	[4],[5]	0		0	0		0
Transfers out of Level 3	[5]	0		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	2,900,000		(2,100,000)	(14,800,000)		(16,800,000)
Ending Balance		(113,200,000)		(112,500,000)	(113,200,000)		(112,500,000)
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	113,300,000			113,300,000			103,600,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	(100,000)			(100,000)			0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	0			0			0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	200,000			200,000			0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	113,200,000			113,200,000			103,600,000
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		113,200,000			113,200,000			103,600,000
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	11.68			11.68			29.23
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	47.28			47.28			61.43
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	28.31			28.31			42.46
Public Service Co Of Oklahoma [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		23,800,000		27,800,000	15,800,000		9,500,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	3,000,000.0		4,100,000	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		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	[3]	0		0	0		0
Settlements		(10,300,000)		(11,200,000)	(27,600,000)		(23,000,000.0)
Transfers into Level 3	[4],[5]	0		0	0		0
Transfers out of Level 3	[5]	0		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	(400,000)		900,000	16,000,000.0		21,600,000
Ending Balance		16,100,000		21,600,000	16,100,000		21,600,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	16,600,000			16,600,000			15,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	500,000			500,000			0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	0			0			(500,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	(100,000)			(100,000)			(500,000)
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	0			0			0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	100,000			100,000			0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	16,600,000			16,600,000			16,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	500,000			500,000			500,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		16,600,000			16,600,000			16,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		500,000			500,000			500,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(5.98)			(5.98)			(8.52)
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	0.70			0.70			0.85
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(1.85)			(1.85)			(2.31)
Southwestern Electric Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		3,300,000		8,500,000	1,400,000		2,300,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	1,500,000		3,600,000	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		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	[3]	0		0	0		0
Settlements		(3,500,000)		(6,700,000)	(6,900,000)		(10,100,000)
Transfers into Level 3	[4],[5]	0		0	0		0
Transfers out of Level 3	[5]	0		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	2,400,000		(500,000)	6,400,000		6,700,000
Ending Balance		3,700,000		$ 4,900,000	3,700,000		$ 4,900,000
Southwestern Electric Power Co [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		4,400,000			4,400,000			6,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		700,000			700,000			5,100,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	4,500,000			4,500,000			6,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	800,000			800,000			5,000,000.0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	100,000			100,000			(100,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	0			0			(100,000)
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	0			0			0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	100,000			100,000			0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	4,400,000			4,400,000			6,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	700,000			700,000			5,100,000
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		600,000			600,000			4,900,000
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	[12]	1.79			1.79			1.89
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	[12]	3.02			3.02			2.51
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	[11],[12]	2.54			2.54			2.18
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		4,400,000			4,400,000			6,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		100,000			100,000			200,000
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(5.98)			(5.98)			(8.52)
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	0.70			0.70			0.85
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(1.85)			(1.85)			(2.31)
Cash [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[14],[15]	79,600,000			79,600,000			214,700,000
Cash [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[14]	13,300,000			13,300,000			17,100,000
Cash [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[14]	66,300,000			66,300,000			197,600,000
Cash [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[14]	0			0			0
Cash [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[14]	0			0			0
Fixed Income Funds [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,248,700,000			1,248,700,000			1,192,500,000
Fixed Income Funds [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Fixed Income Funds [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Fixed Income Funds [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,248,700,000			1,248,700,000			1,192,500,000
Fixed Income Funds [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,248,700,000			1,248,700,000			1,192,500,000
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			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			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		1,248,700,000			1,248,700,000			1,192,500,000
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Mutual Funds Fixed Income [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	130,800,000			130,800,000			123,300,000
Mutual Funds Fixed Income [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Mutual Funds Fixed Income [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		130,800,000			130,800,000			123,300,000
Mutual Funds Fixed Income [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Mutual Funds Fixed Income [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Mutual Funds Equity [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[17]	52,700,000			52,700,000			50,500,000
Mutual Funds Equity [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[17]	0			0			0
Mutual Funds Equity [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[17]	52,700,000			52,700,000			50,500,000
Mutual Funds Equity [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[17]	0			0			0
Mutual Funds Equity [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[17]	0			0			0
Cash and Cash Equivalents [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	33,700,000			33,700,000			15,300,000
Cash and Cash Equivalents [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	9,000,000.0			9,000,000.0			8,600,000
Cash and Cash Equivalents [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	24,700,000			24,700,000			6,700,000
Cash and Cash Equivalents [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	0			0			0
Cash and Cash Equivalents [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	0			0			0
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	33,700,000			33,700,000			15,300,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	9,000,000.0			9,000,000.0			8,600,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	24,700,000			24,700,000			6,700,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	0			0			0
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	0			0			0
US Government Agencies Debt Securities [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,039,200,000			1,039,200,000			1,112,500,000
US Government Agencies Debt Securities [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
US Government Agencies Debt Securities [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
US Government Agencies Debt Securities [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,039,200,000			1,039,200,000			1,112,500,000
US Government Agencies Debt Securities [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,039,200,000			1,039,200,000			1,112,500,000
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			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			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		1,039,200,000			1,039,200,000			1,112,500,000
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		85,600,000			85,600,000			72,400,000
Corporate Debt [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		85,600,000			85,600,000			72,400,000
Corporate Debt [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		85,600,000			85,600,000			72,400,000
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		85,600,000			85,600,000			72,400,000
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
State and Local Jurisdiction [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		123,900,000			123,900,000			7,600,000
State and Local Jurisdiction [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
State and Local Jurisdiction [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
State and Local Jurisdiction [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		123,900,000			123,900,000			7,600,000
State and Local Jurisdiction [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		123,900,000			123,900,000			7,600,000
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		123,900,000			123,900,000			7,600,000
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Domestic [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	1,793,500,000			1,793,500,000			1,767,900,000
Domestic [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0			0
Domestic [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	1,793,500,000			1,793,500,000			1,767,900,000
Domestic [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0			0
Domestic [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0			0
Domestic [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	1,793,500,000			1,793,500,000			1,767,900,000
Domestic [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0			0
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	1,793,500,000			1,793,500,000			1,767,900,000
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0			0
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	$ 0			$ 0			$ 0

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

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

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

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

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

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

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

[8] The September 30, 2020 maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), is as follows: Level 2 matures $(6) million in 2020, $3 million in periods 2021-2023, $4 million in periods 2024-2025 and $7 million in periods 2026-2033; Level 3 matures $35 million in 2020, $63 million in periods 2021-2023, $21 million in periods 2024-2025 and $(12) million in periods 2026-2033.  Risk management commodity contracts are substantially comprised of power contracts.

[9] The December 31, 2019 maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), is as follows: Level 2 matures $(7) million in 2020 and $(3) million in periods 2021-2023; Level 3 matures $96 million in 2020, $36 million in periods 2021-2023, $25 million in periods 2024-2025 and $(12) million in periods 2026-2032.  Risk management commodity contracts are substantially comprised of power contracts.

[10] Represents market prices in dollars per MWh.

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

[12] Represents market prices in dollars per MMBtu.

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

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

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

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

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