Fair Value Assets and Liabilities (Details) - USD ($)		3 Months Ended			9 Months Ended
		Sep. 30, 2019		Sep. 30, 2018	Sep. 30, 2019		Sep. 30, 2018	Dec. 31, 2018
Assets, Fair Value Disclosure
Other Short-term Investments		$ 339,400,000			$ 339,400,000			$ 369,100,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,835,200,000			2,835,200,000			2,474,900,000
Total Assets		3,660,300,000			3,660,300,000			3,260,800,000
Risk Management Assets
Risk Management Assets		485,700,000			485,700,000			416,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		373,900,000			373,900,000			318,400,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		112,700,000		$ 172,300,000	131,200,000		$ 40,300,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	30,200,000		19,900,000	14,600,000		150,900,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[1]	2,900,000		1,500,000	32,900,000		9,500,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)		22,100,000		10,400,000	(42,800,000)		16,400,000
Settlements		(67,400,000)		(56,000,000.0)	(114,600,000)		(212,300,000)
Transfers into Level 3	[3],[4]	3,500,000		2,300,000	400,000		16,500,000
Transfers out of Level 3	[4]	6,600,000		(1,200,000)	1,400,000		(2,500,000)
Changes in Fair Value Allocated to Regulated Jurisdiction	[5]	(300,000)		12,000,000.0	87,200,000		142,400,000
Ending Balance		110,300,000		161,200,000	110,300,000		161,200,000
Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		7,200,000			7,200,000			9,100,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		8,000,000.0			8,000,000.0			10,200,000
Total Assets		(188,300,000)			(188,300,000)			(271,900,000)
Risk Management Assets
Risk Management Assets		(203,500,000)			(203,500,000)			(291,200,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(224,700,000)			(224,700,000)			(277,400,000)
Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		332,200,000			332,200,000			360,000,000.0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,703,700,000			1,703,700,000			1,407,600,000
Total Assets		2,041,500,000			2,041,500,000			1,771,400,000
Risk Management Assets
Risk Management Assets		5,600,000			5,600,000			3,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		5,100,000			5,100,000			4,200,000
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		1,123,500,000			1,123,500,000			1,057,100,000
Total Assets		1,396,500,000			1,396,500,000			1,407,700,000
Risk Management Assets
Risk Management Assets		273,000,000.0			273,000,000.0			350,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		293,200,000			293,200,000			369,200,000
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		410,600,000			410,600,000			353,600,000
Risk Management Assets
Risk Management Assets		410,600,000			410,600,000			353,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		300,300,000			300,300,000			222,400,000
2019 [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)			(4,000,000)
2019 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		40,000,000			40,000,000			108,000,000
2020 - 2022 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(8,000,000)			(8,000,000)			1,000,000
2020 - 2022 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		114,000,000			114,000,000			37,000,000
2023 - 2024 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities								1,000,000
2023 - 2024 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		26,000,000			26,000,000			23,000,000
2025 - 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		(1,000,000)			(1,000,000)			1,000,000
2025 - 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		(4,000,000)			(4,000,000)			(12,000,000)
Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[6]	446,200,000	[7]		446,200,000	[7]		382,700,000	[8]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	264,100,000	[7]		264,100,000	[7]		242,100,000	[8]
Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[6]	(195,300,000)	[7]		(195,300,000)	[7]		(288,500,000)	[8]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	(216,500,000)	[7]		(216,500,000)	[7]		(274,700,000)	[8]
Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[6]	5,600,000	[7]		5,600,000	[7]		3,800,000	[8]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	5,100,000	[7]		5,100,000	[7]		4,200,000	[8]
Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[6]	228,200,000	[7]		228,200,000	[7]		326,500,000	[8]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	243,900,000	[7]		243,900,000	[7]		327,000,000.0	[8]
Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[6]	407,700,000	[7]		407,700,000	[7]		340,900,000	[8]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	231,600,000	[7]		231,600,000	[7]		185,600,000	[8]
Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		298,800,000			298,800,000			257,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		286,800,000			286,800,000			212,500,000
Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	(0.05)			(0.05)			(0.05)
Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	180.10			180.10			176.57
Energy Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	31.34			31.34			33.07
Natural Gas Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		4,500,000			4,500,000			2,500,000
Natural Gas Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	1.96			1.96			2.18
Natural Gas Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	2.62			2.62			3.54
Natural Gas Contracts [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	2.25			2.25			2.47
FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		111,800,000			111,800,000			96,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		9,000,000.0			9,000,000.0			7,400,000
FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	(10.40)			(10.40)			(11.68)
FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	11.65			11.65			17.79
FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	0.54			0.54			1.09
Commodity Hedges [Member]
Risk Management Assets
Risk Management Assets	[6]	12,300,000			12,300,000			34,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	109,600,000			109,600,000			58,900,000
Commodity Hedges [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[6]	(8,200,000)			(8,200,000)			(2,700,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	(8,200,000)			(8,200,000)			(2,700,000)
Commodity Hedges [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[6]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	0			0			0
Commodity Hedges [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[6]	17,600,000			17,600,000			24,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	49,100,000			49,100,000			24,800,000
Commodity Hedges [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[6]	2,900,000			2,900,000			12,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	68,700,000			68,700,000			36,800,000
Interest Rate [Member]
Risk Management Assets
Risk Management Assets		1,900,000			1,900,000
Interest Rate [Member] | Other [Member]
Risk Management Assets
Risk Management Assets		0			0
Interest Rate [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets		0			0
Interest Rate [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets		1,900,000			1,900,000
Interest Rate [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		0			0
Fair Value Hedges [Member]
Risk Management Assets
Risk Management Assets		25,300,000			25,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		200,000			200,000			17,400,000
Fair Value Hedges [Member] | Other [Member]
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			0
Fair Value Hedges [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			0
Fair Value Hedges [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets		25,300,000			25,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		200,000			200,000			17,400,000
Fair Value Hedges [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			0
AEP Texas Inc. [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		114,300,000			114,300,000			156,700,000
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		114,300,000			114,300,000			156,700,000
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	[6]	400,000			400,000			200,000
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	0			0			(500,000)
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	0			0			0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	400,000			400,000			700,000
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6]	0			0			0
Appalachian Power Co [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		17,100,000			17,100,000			25,600,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		73,800,000			73,800,000			83,700,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		68,500,000		60,000,000.0	57,800,000		24,700,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	13,800,000		9,000,000.0	(14,100,000)		104,400,000
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)		0		0	0		0
Settlements		(28,100,000)		(19,800,000)	(41,900,000)		(128,300,000)
Transfers into Level 3	[3],[4]	0		0	0		0
Transfers out of Level 3	[4]	0		0	(700,000)		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[5]	1,300,000		17,300,000	54,400,000		65,700,000
Ending Balance		55,500,000		66,500,000	55,500,000		66,500,000
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		(32,000,000.0)			(32,000,000.0)			(59,400,000)
Appalachian Power Co [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		17,100,000			17,100,000			25,600,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		17,100,000			17,100,000			25,700,000
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		31,400,000			31,400,000			59,100,000
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		57,300,000			57,300,000			58,300,000
Risk Management Assets
Risk Management Assets		57,300,000			57,300,000			58,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		1,800,000			1,800,000			500,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	56,700,000			56,700,000			58,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	1,400,000			1,400,000			600,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	(32,000,000.0)			(32,000,000.0)			(59,400,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	(33,600,000)			(33,600,000)			(58,500,000)
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	0			0			100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	0			0			200,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	31,400,000			31,400,000			59,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	33,200,000			33,200,000			58,400,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	57,300,000			57,300,000			58,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	1,800,000			1,800,000			500,000
Appalachian Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		3,600,000			3,600,000			2,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		1,100,000			1,100,000			500,000
Appalachian Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	12.93			12.93			16.82
Appalachian Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	59.25			59.25			62.65
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	[9]	31.28			31.28			37.00
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		53,700,000			53,700,000			55,900,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		700,000			700,000			0
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	(0.91)			(0.91)			0.10
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	10.14			10.14			15.16
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] | Weighted Average [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	1.63			1.63			3.27
Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,835,200,000			2,835,200,000			2,474,900,000
Total Assets		2,845,800,000			2,845,800,000			2,484,100,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		12,300,000		13,200,000	8,900,000		7,600,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	3,100,000		1,900,000	4,600,000		14,700,000
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)		0		0	0		0
Settlements		(7,200,000)		(5,500,000)	(12,600,000)		(21,900,000)
Transfers into Level 3	[3],[4]	0		0	0		0
Transfers out of Level 3	[4]	0		0	(400,000)		(300,000)
Changes in Fair Value Allocated to Regulated Jurisdiction	[5]	700,000		(200,000)	8,400,000		9,300,000
Ending Balance		8,900,000		9,400,000	8,900,000		9,400,000
Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		8,000,000.0			8,000,000.0			10,200,000
Total Assets		(13,500,000)			(13,500,000)			(33,000,000.0)
Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,703,700,000			1,703,700,000			1,407,600,000
Total Assets		1,703,700,000			1,703,700,000			1,407,600,000
Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,123,500,000			1,123,500,000			1,057,100,000
Total Assets		1,145,400,000			1,145,400,000			1,099,200,000
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		10,200,000			10,200,000			10,300,000
Risk Management Assets
Risk Management Assets		10,200,000			10,200,000			10,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		1,300,000			1,300,000			1,400,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	10,600,000			10,600,000			9,200,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	200,000			200,000			400,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	(21,500,000)			(21,500,000)			(43,200,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	(22,400,000)			(22,400,000)			(42,300,000)
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	0			0			100,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	21,900,000			21,900,000			42,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	21,300,000			21,300,000			41,200,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	10,200,000			10,200,000			10,300,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	1,300,000			1,300,000			1,400,000
Indiana Michigan Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		2,200,000			2,200,000			1,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		700,000			700,000			900,000
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	[9]	12.93			12.93			16.82
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	[9]	59.25			59.25			62.65
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	[9]	31.28			31.28			37.00
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		8,000,000.0			8,000,000.0			8,900,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		600,000			600,000			500,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	(1.76)			(1.76)			(2.11)
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	7.26			7.26			6.21
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	[9]	0.87			0.87			1.06
Ohio Power Co [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents								27,600,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		(111,500,000)		(86,900,000)	(99,400,000)		(132,400,000)
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	0		0	(900,000)		1,300,000
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)		0		0	0		0
Settlements		1,100,000		600,000	4,600,000		3,000,000.0
Transfers into Level 3	[3],[4]	0		0	0		0
Transfers out of Level 3	[4]	0		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[5]	(2,100,000)		(8,900,000)	(16,800,000)		32,900,000
Ending Balance		(112,500,000)		(95,200,000)	(112,500,000)		(95,200,000)
Ohio Power Co [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents								0
Ohio Power Co [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents								27,600,000
Ohio Power Co [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents								0
Ohio Power Co [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents								0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	112,900,000			112,900,000			99,600,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	0			0			(600,000)
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	0			0			0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	400,000			400,000			800,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	112,500,000			112,500,000			99,400,000
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		112,500,000			112,500,000			99,400,000
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	27.47			27.47			26.29
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	65.81			65.81			62.74
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	[9]	40.30			40.30			42.50
Public Service Co Of Oklahoma [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		27,800,000		24,300,000	9,500,000		6,200,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	4,100,000		3,700,000	13,500,000		18,100,000
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)		0		0	0		0
Settlements		(11,200,000)		(10,800,000)	(23,000,000.0)		(24,300,000)
Transfers into Level 3	[3],[4]	0		0	0		0
Transfers out of Level 3	[4]	0		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[5]	900,000		400,000	21,600,000		17,600,000
Ending Balance		21,600,000		17,600,000	21,600,000		17,600,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	21,700,000			21,700,000			10,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	300,000			300,000			1,000,000.0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	(300,000)			(300,000)			(400,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	(300,000)			(300,000)			(600,000)
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	0			0			0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	200,000			200,000			300,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	22,000,000.0			22,000,000.0			10,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	400,000			400,000			1,300,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		22,000,000.0			22,000,000.0			10,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		400,000			400,000			1,300,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	(6.87)			(6.87)			(11.68)
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	[9]	0.93			0.93			10.30
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	[9]	(2.19)			(2.19)			(1.40)
Southwestern Electric Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		8,500,000		4,900,000	2,300,000		5,900,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	[1],[2]	3,600,000		1,700,000	6,000,000.0		(4,800,000)
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)		0		0	0		0
Settlements		(6,700,000)		(2,700,000)	(10,100,000)		(1,300,000)
Transfers into Level 3	[3],[4]	0		0	0		0
Transfers out of Level 3	[4]	0		0	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[5]	(500,000)		(400,000)	6,700,000		3,700,000
Ending Balance		4,900,000		$ 3,500,000	4,900,000		$ 3,500,000
Southwestern Electric Power Co [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		9,800,000			9,800,000			5,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		4,900,000			4,900,000			3,300,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	9,400,000			9,400,000			4,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	4,700,000			4,700,000			2,600,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	(400,000)			(400,000)			(800,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	(400,000)			(400,000)			(1,100,000)
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	0			0			0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	200,000			200,000			400,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	[6],[11]	9,800,000			9,800,000			5,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[6],[11]	4,900,000			4,900,000			3,300,000
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		4,500,000			4,500,000			2,500,000
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	[10]	1.96			1.96			2.18
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	2.62			2.62			3.54
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	[10]	2.25			2.25			2.47
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets		9,800,000			9,800,000			5,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		400,000			400,000			800,000
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | Low [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	(6.87)			(6.87)			(11.68)
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] | High [Member]
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[9]	0.93			0.93			10.30
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	[9]	(2.19)			(2.19)			(1.40)
Cash [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[12],[13]	160,100,000			160,100,000			230,600,000
Cash [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[13]	7,200,000			7,200,000			9,100,000
Cash [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[13]	152,900,000			152,900,000			221,500,000
Cash [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[13]	0			0			0
Cash [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[13]	0			0			0
Fixed Income Funds [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,123,500,000			1,123,500,000			1,057,100,000
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		1,123,500,000			1,123,500,000			1,057,100,000
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		1,123,500,000			1,123,500,000			1,057,100,000
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		1,123,500,000			1,123,500,000			1,057,100,000
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	[14]	133,200,000			133,200,000			104,300,000
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		133,200,000			133,200,000			104,300,000
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	[15]	46,100,000			46,100,000			34,200,000
Mutual Funds Equity [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[15]	0			0			0
Mutual Funds Equity [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[15]	46,100,000			46,100,000			34,200,000
Mutual Funds Equity [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[15]	0			0			0
Mutual Funds Equity [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[15]	0			0			0
Cash and Cash Equivalents [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	17,400,000			17,400,000			22,500,000
Cash and Cash Equivalents [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	8,000,000.0			8,000,000.0			10,200,000
Cash and Cash Equivalents [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	9,400,000			9,400,000			12,300,000
Cash and Cash Equivalents [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	0			0			0
Cash and Cash Equivalents [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	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	[16]	17,400,000			17,400,000			22,500,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	8,000,000.0			8,000,000.0			10,200,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	9,400,000			9,400,000			12,300,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	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	[16]	0			0			0
US Government Agencies Debt Securities [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,047,400,000			1,047,400,000			996,100,000
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		1,047,400,000			1,047,400,000			996,100,000
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		1,047,400,000			1,047,400,000			996,100,000
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		1,047,400,000			1,047,400,000			996,100,000
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		68,600,000			68,600,000			52,400,000
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		68,600,000			68,600,000			52,400,000
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		68,600,000			68,600,000			52,400,000
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		68,600,000			68,600,000			52,400,000
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		7,500,000			7,500,000			8,600,000
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		7,500,000			7,500,000			8,600,000
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		7,500,000			7,500,000			8,600,000
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		7,500,000			7,500,000			8,600,000
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	[15]	1,694,300,000			1,694,300,000			1,395,300,000
Domestic [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[15]	0			0			0
Domestic [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[15]	1,694,300,000			1,694,300,000			1,395,300,000
Domestic [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[15]	0			0			0
Domestic [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[15]	0			0			0
Domestic [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[15]	1,694,300,000			1,694,300,000			1,395,300,000
Domestic [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[15]	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	[15]	1,694,300,000			1,694,300,000			1,395,300,000
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[15]	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	[15]	$ 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] Represents existing assets or liabilities that were previously categorized as Level 2.

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

[5] 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.

[6] 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.’’

[7] The September 30, 2019 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 2019, $(8) million in periods 2020-2022 and $(1) million in periods 2025-2032; Level 3 matures $40 million in 2019, $114 million in periods 2020-2022, $26 million in periods 2023-2024 and $(4) million in periods 2025-2032.  Risk management commodity contracts are substantially comprised of power contracts.

[8] The December 31, 2018 maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), is as follows: Level 2 matures $(4) million in 2019, $1 million in periods 2020-2022, $1 million in periods 2023-2024 and $1 million in periods 2025-2032; Level 3 matures $108 million in 2019, $37 million in periods 2020-2022, $23 million in periods 2023-2024 and $(12) million in periods 2025-2032.  Risk management commodity contracts are substantially comprised of power contracts.

[9] Represents market prices in dollars per MWh.

[10] Represents market prices in dollars per MMBtu.

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

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

[13] Amounts in “Other’’ column primarily represent cash deposits in bank accounts with financial institutions or third-parties.  Level 1 and Level 2 amounts primarily represent investments in money market funds.

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

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

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