Fair Value Assets and Liabilities (Details) - USD ($)		3 Months Ended			6 Months Ended
		Jun. 30, 2020		Jun. 30, 2019	Jun. 30, 2020		Jun. 30, 2019	Dec. 31, 2019
Assets, Fair Value Disclosure
Other Short-term Investments		$ 348,200,000			$ 348,200,000			$ 388,500,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,957,000,000.0			2,957,000,000.0			2,975,700,000
Total Assets		3,702,400,000			3,702,400,000			3,803,600,000
Risk Management Assets
Risk Management Assets		397,200,000			397,200,000			439,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		347,700,000			347,700,000			376,100,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		42,500,000		$ 38,100,000	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]	39,100,000		36,500,000	38,200,000		32,700,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	(17,200,000)		21,600,000	(6,400,000)		29,200,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	[3]	22,000,000.0		(53,500,000)	18,300,000		(69,200,000)
Settlements		(54,700,000)		(50,600,000)	(113,700,000)		(126,600,000)
Transfers into Level 3	[4],[5]			(1,500,000)	(600,000)		(1,400,000)
Transfers out of Level 3	[5]	(200,000)		(1,600,000)	4,300,000		(2,700,000)
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	80,100,000		123,700,000	61,600,000		119,500,000
Ending Balance		111,600,000		112,700,000	111,600,000		112,700,000
Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		18,500,000			18,500,000			17,100,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		9,900,000			9,900,000			8,600,000
Total Assets		(253,700,000)			(253,700,000)			(385,500,000)
Risk Management Assets
Risk Management Assets		(282,100,000)			(282,100,000)			(411,200,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(317,700,000)			(317,700,000)			(445,500,000)
Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		329,700,000			329,700,000			371,400,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,722,600,000			1,722,600,000			1,774,600,000
Total Assets		2,055,000,000.0			2,055,000,000.0			2,150,000,000.0
Risk Management Assets
Risk Management Assets		2,700,000			2,700,000			4,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		3,700,000			3,700,000			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		1,224,500,000			1,224,500,000			1,192,500,000
Total Assets		1,584,400,000			1,584,400,000			1,666,700,000
Risk Management Assets
Risk Management Assets		359,900,000			359,900,000			474,200,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		456,600,000			456,600,000			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		316,700,000			316,700,000			372,400,000
Risk Management Assets
Risk Management Assets		316,700,000			316,700,000			372,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		205,100,000			205,100,000			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		(10,000,000)			(10,000,000)			(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		60,000,000			60,000,000			96,000,000
2021 - 2023 [Member] | Level 1 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(1,000,000)			(1,000,000)
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		(1,000,000)			(1,000,000)			(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		61,000,000			61,000,000			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		20,000,000			20,000,000			25,000,000
2026 - 2032 [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			10,000,000
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		(22,000,000)			(22,000,000)			(12,000,000)
Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7]	384,500,000	[8]		384,500,000	[8]		408,800,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	228,300,000	[8]		228,300,000	[8]		239,000,000.0	[9]
Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7]	(262,900,000)	[8]		(262,900,000)	[8]		(404,500,000)	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	(298,500,000)	[8]		(298,500,000)	[8]		(438,800,000)	[9]
Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[7]	2,700,000	[8]		2,700,000	[8]		4,000,000.0	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	3,700,000	[8]		3,700,000	[8]		3,800,000	[9]
Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[7]	331,200,000	[8]		331,200,000	[8]		440,100,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	328,800,000	[8]		328,800,000	[8]		450,000,000.0	[9]
Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7]	313,500,000	[8]		313,500,000	[8]		369,200,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	194,300,000	[8]		194,300,000	[8]		224,000,000.0	[9]
Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		232,100,000			232,100,000			296,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		196,500,000			196,500,000			249,300,000
Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	4.76			4.76			(0.05)
Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	112.91			112.91			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]	31.49			31.49			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		3,600,000			3,600,000			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]	1.44			1.44			1.89
Natural Gas Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]	2.66			2.66			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]	2.23			2.23			2.19
FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		84,600,000			84,600,000			75,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		5,000,000.0			5,000,000.0			8,300,000
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)
FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	7.47			7.47			9.34
FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.12			0.12			0.42
Commodity Hedges [Member]
Risk Management Assets
Risk Management Assets	[7]	12,600,000			12,600,000			11,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	113,500,000			113,500,000			137,100,000
Commodity Hedges [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7]	(19,200,000)			(19,200,000)			(6,700,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	(19,200,000)			(19,200,000)			(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]	28,600,000			28,600,000			15,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	121,900,000			121,900,000			105,300,000
Commodity Hedges [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7]	3,200,000			3,200,000			3,200,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7]	10,800,000			10,800,000			38,500,000
Interest Rate [Member]
Risk Management Assets
Risk Management Assets		100,000			100,000			4,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		5,900,000			5,900,000
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		100,000			100,000			4,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		5,900,000			5,900,000
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		136,600,000			136,600,000			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		136,600,000			136,600,000			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]	(400,000)			(400,000)
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]	500,000			500,000
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		19,300,000			19,300,000			23,500,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		57,400,000			57,400,000			63,000,000.0
Risk Management Assets
Risk Management Assets		38,100,000			38,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		7,800,000			7,800,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		6,600,000		7,400,000	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]	23,500,000		17,300,000	12,900,000		(13,600,000)
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		(28,900,000)		(22,100,000)	(50,800,000)		(41,100,000)
Transfers into Level 3	[4],[5]			0	0		0
Transfers out of Level 3	[5]	0		0	700,000		(700,000)
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	35,300,000		65,900,000	36,000,000.0		66,100,000
Ending Balance		36,500,000		68,500,000	36,500,000		68,500,000
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		(35,400,000)			(35,400,000)			(85,600,000)
Risk Management Assets
Risk Management Assets		(35,400,000)			(35,400,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(35,900,000)			(35,900,000)
Appalachian Power Co [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		19,300,000			19,300,000			23,500,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		19,300,000			19,300,000			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		36,200,000			36,200,000			84,600,000
Risk Management Assets
Risk Management Assets		36,200,000			36,200,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		42,900,000			42,900,000
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		37,300,000			37,300,000			40,500,000
Risk Management Assets
Risk Management Assets		37,300,000			37,300,000			40,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		800,000			800,000			2,800,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	38,000,000.0			38,000,000.0			39,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	1,900,000			1,900,000			1,900,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	(35,400,000)			(35,400,000)			(85,600,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	(35,900,000)			(35,900,000)			(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]	36,100,000			36,100,000			84,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	37,000,000.0			37,000,000.0			84,000,000.0
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	37,300,000			37,300,000			40,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	800,000			800,000			2,800,000
Appalachian Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		1,900,000			1,900,000			5,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		700,000			700,000			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]	8.53			8.53			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]	40.35			40.35			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]	25.34			25.34			25.92
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		35,400,000			35,400,000			34,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		100,000			100,000			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]	(0.79)			(0.79)			(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]	6.55			6.55			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]	0.95			0.95			1.70
Appalachian Power Co [Member] | Interest Rate [Member]
Risk Management Assets
Risk Management Assets		100,000			100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		5,900,000			5,900,000
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		100,000			100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		5,900,000			5,900,000
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		2,957,000,000.0			2,957,000,000.0			2,975,700,000
Total Assets		2,963,700,000			2,963,700,000			2,985,600,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		2,100,000		4,400,000	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]	2,800,000		3,300,000	2,300,000		4,300,000
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		(4,100,000)		(6,300,000)	(8,100,000)		(11,800,000)
Transfers into Level 3	[4],[5]			0	0		0
Transfers out of Level 3	[5]	0		0	400,000		(400,000)
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	3,700,000		10,900,000	4,100,000		11,300,000
Ending Balance		4,500,000		12,300,000	4,500,000		12,300,000
Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		9,900,000			9,900,000			8,600,000
Total Assets		(13,400,000)			(13,400,000)			(49,000,000.0)
Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,722,600,000			1,722,600,000			1,774,600,000
Total Assets		1,722,600,000			1,722,600,000			1,774,600,000
Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,224,500,000			1,224,500,000			1,192,500,000
Total Assets		1,249,500,000			1,249,500,000			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		5,000,000.0			5,000,000.0			8,000,000.0
Risk Management Assets
Risk Management Assets		5,000,000.0			5,000,000.0			8,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		500,000			500,000			2,200,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	6,700,000			6,700,000			9,900,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	500,000			500,000			500,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	(23,300,000)			(23,300,000)			(57,600,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	(23,400,000)			(23,400,000)			(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]	25,000,000.0			25,000,000.0			59,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	23,400,000			23,400,000			53,400,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	5,000,000.0			5,000,000.0			8,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	500,000			500,000			2,200,000
Indiana Michigan Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		1,200,000			1,200,000			3,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		400,000			400,000			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]	8.53			8.53			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]	40.35			40.35			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]	25.34			25.34			25.92
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		3,800,000			3,800,000			4,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		100,000			100,000			700,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(2.69)			(2.69)			(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]	4.69			4.69			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]	0.31			0.31			0.74
Ohio Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		(120,900,000)		(106,100,000)	(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		(100,000)	(900,000)		(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		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		2,600,000		1,900,000	5,100,000		3,600,000
Transfers into Level 3	[4],[5]			0	0		0
Transfers out of Level 3	[5]	0		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	900,000		(7,200,000)	(18,000,000.0)		(15,000,000.0)
Ending Balance		(117,400,000)		(111,500,000)	(117,400,000)		(111,500,000)
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	117,500,000			117,500,000			103,600,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	(300,000)			(300,000)			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]	400,000			400,000			0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	117,400,000			117,400,000			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		117,400,000			117,400,000			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]	12.38			12.38			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]	44.46			44.46			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]	27.32			27.32			42.46
Public Service Co Of Oklahoma [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		6,300,000		4,400,000	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]	3,900,000		7,200,000	11,900,000		22,800,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	0		0	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		(10,200,000)		(10,000,000.0)	(27,600,000)		(32,300,000)
Transfers into Level 3	[4],[5]			0	0		0
Transfers out of Level 3	[5]	0		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	23,800,000		26,200,000	23,700,000		27,800,000
Ending Balance		23,800,000		27,800,000	23,800,000		27,800,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	23,800,000			23,800,000			15,800,000
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] | Other [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	(100,000)			(100,000)			(500,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	(300,000)			(300,000)			(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]	300,000			300,000			0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	23,900,000			23,900,000			16,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	100,000			100,000			500,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		23,900,000			23,900,000			16,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		100,000			100,000			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]	0.57			0.57			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]	(1.63)			(1.63)			(2.31)
Southwestern Electric Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		(2,500,000)		0	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]	800,000		2,200,000	2,800,000		16,200,000
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		(2,400,000)		(3,300,000)	(7,600,000)		(20,800,000)
Transfers into Level 3	[4],[5]			0	0		0
Transfers out of Level 3	[5]	0		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	7,400,000		9,600,000	6,700,000		10,800,000
Ending Balance		3,300,000		$ 8,500,000	3,300,000		$ 8,500,000
Southwestern Electric Power Co [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		7,000,000.0			7,000,000.0			6,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		3,700,000			3,700,000			5,100,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	6,900,000			6,900,000			6,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	3,700,000			3,700,000			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]	(300,000)			(300,000)			(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]	300,000			300,000			0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[7],[13]	7,000,000.0			7,000,000.0			6,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[7],[13]	3,700,000			3,700,000			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		3,600,000			3,600,000			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]	1.44			1.44			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]	2.66			2.66			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]	2.23			2.23			2.18
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		7,000,000.0			7,000,000.0			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]	0.57			0.57			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]	(1.63)			(1.63)			(2.31)
Cash [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[14],[15]	186,500,000			186,500,000			214,700,000
Cash [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[14]	18,500,000			18,500,000			17,100,000
Cash [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[14]	168,000,000.0			168,000,000.0			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		1,224,500,000			1,224,500,000			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		1,224,500,000			1,224,500,000			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		1,224,500,000			1,224,500,000			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		1,224,500,000			1,224,500,000			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]	115,600,000			115,600,000			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		115,600,000			115,600,000			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]	46,100,000			46,100,000			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]	46,100,000			46,100,000			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]	70,500,000			70,500,000			15,300,000
Cash and Cash Equivalents [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	9,900,000			9,900,000			8,600,000
Cash and Cash Equivalents [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[18]	60,600,000			60,600,000			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]	70,500,000			70,500,000			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]	9,900,000			9,900,000			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]	60,600,000			60,600,000			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		988,100,000			988,100,000			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		988,100,000			988,100,000			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		988,100,000			988,100,000			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		988,100,000			988,100,000			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		74,900,000			74,900,000			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		74,900,000			74,900,000			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		74,900,000			74,900,000			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		74,900,000			74,900,000			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		161,500,000			161,500,000			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		161,500,000			161,500,000			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		161,500,000			161,500,000			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		161,500,000			161,500,000			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]	1,662,000,000.0			1,662,000,000.0			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]	1,662,000,000.0			1,662,000,000.0			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]	1,662,000,000.0			1,662,000,000.0			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]	1,662,000,000.0			1,662,000,000.0			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 June 30, 2020 maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), is as follows: Level 1 matures $(1) million in periods 2021-2023; Level 2 matures $(10) million in 2020, $(1) million in periods 2021-2023, $4 million in periods 2024-2025 and $10 million in periods 2026-2032; Level 3 matures $60 million in 2020, $61 million in periods 2021-2023, $20 million in periods 2024-2025 and $(22) million in periods 2026-2032.  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.