Fair Value Assets and Liabilities (Details) - USD ($)		3 Months Ended			9 Months Ended
		Sep. 30, 2024		Sep. 30, 2023	Sep. 30, 2024		Sep. 30, 2023	Dec. 31, 2023
Risk Management Assets		$ 495,000,000.0			$ 495,000,000.0			$ 538,700,000
Risk Management Liabilities		353,600,000			353,600,000			471,400,000
Assets, Fair Value Disclosure
Other Short-term Investments		282,000,000.0			282,000,000.0			263,200,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		4,425,800,000			4,425,800,000			3,860,200,000
Total Assets		(5,202,800,000)			(5,202,800,000)			(4,662,100,000)
Risk Management Assets
Risk Management Assets		495,000,000.0			495,000,000.0			538,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		353,600,000			353,600,000			471,400,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		288,200,000		$ 126,100,000	139,400,000		$ 160,400,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	60,400,000		39,700,000	90,600,000		(41,300,000)
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	(6,900,000)		72,700,000	2,300,000		67,700,000
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	(100,000)		4,900,000	1,500,000		(10,500,000)
Settlements		(133,100,000)		(87,100,000)	(164,700,000)		(85,900,000)
Transfers into Level 3	[4],[5]	(300,000)			6,800,000		(6,100,000)
Transfers out of Level 3	[5]	(600,000)		6,600,000	2,200,000		3,800,000
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	(14,500,000)		19,900,000	115,000,000.0		94,700,000
Ending Balance		193,100,000		182,800,000	193,100,000		182,800,000
Level 1 [Member]
Risk Management Assets		3,900,000			3,900,000			9,700,000
Risk Management Liabilities		7,500,000			7,500,000			24,700,000
Assets, Fair Value Disclosure
Other Short-term Investments		265,000,000.0			265,000,000.0			249,300,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,827,400,000			2,827,400,000			2,444,400,000
Total Assets		(3,096,300,000)			(3,096,300,000)			(2,703,400,000)
Risk Management Assets
Risk Management Assets		3,900,000			3,900,000			9,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		7,500,000			7,500,000			24,700,000
Level 2 [Member]
Risk Management Assets		655,400,000			655,400,000			860,400,000
Risk Management Liabilities		675,900,000			675,900,000			900,800,000
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,587,800,000			1,587,800,000			1,406,800,000
Total Assets		(2,243,200,000)			(2,243,200,000)			(2,267,200,000)
Risk Management Assets
Risk Management Assets		655,400,000			655,400,000			860,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		675,900,000			675,900,000			900,800,000
Level 3 [Member]
Risk Management Assets		327,300,000			327,300,000			294,100,000
Risk Management Liabilities		134,200,000			134,200,000			154,700,000
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		(327,300,000)			(327,300,000)			(294,100,000)
Risk Management Assets
Risk Management Assets		327,300,000			327,300,000			294,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		134,200,000			134,200,000			154,700,000
Other [Member]
Risk Management Assets		(491,600,000)			(491,600,000)			(625,500,000)
Risk Management Liabilities		(464,000,000.0)			(464,000,000.0)			(608,800,000)
Assets, Fair Value Disclosure
Other Short-term Investments		17,000,000.0			17,000,000.0			13,900,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		10,600,000			10,600,000			9,000,000.0
Total Assets		(464,000,000.0)			(464,000,000.0)			(602,600,000)
Risk Management Assets
Risk Management Assets		(491,600,000)			(491,600,000)			(625,500,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(464,000,000.0)			(464,000,000.0)			(608,800,000)
2024 [Member] | Level 1 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(1,000,000)			(1,000,000)			(11,000,000)
2024 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(23,000,000)			(23,000,000)			(99,000,000)
2024 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		45,000,000			45,000,000			74,000,000
2025 - 2027 [Member] | Level 1 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(2,000,000)			(2,000,000)			(4,000,000)
2025 - 2027 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		15,000,000			15,000,000			(44,000,000)
2025 - 2027 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		129,000,000			129,000,000			43,000,000
2028 - 2029 [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		5,000,000			5,000,000			7,000,000
2028 - 2029 [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		17,000,000			17,000,000			18,000,000
Maturity Period Four [Member] | Level 2 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities								2,000,000
Maturity Period Four [Member] | Level 3 [Member]
Fair Value Measurements 1 (Textuals)
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities		(18,000,000)			(18,000,000)			(16,000,000)
Risk Management Commodity Contracts [Member]
Risk Management Assets	[8]	398,500,000	[7]		398,500,000	[7]		403,900,000	[9]
Risk Management Liabilities	[8]	259,400,000	[7]		259,400,000	[7]		362,300,000	[9]
Risk Management Assets
Risk Management Assets	[8]	398,500,000	[7]		398,500,000	[7]		403,900,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	259,400,000	[7]		259,400,000	[7]		362,300,000	[9]
Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[8]	3,900,000	[7]		3,900,000	[7]		9,700,000	[9]
Risk Management Liabilities	[8]	7,500,000	[7]		7,500,000	[7]		24,700,000	[9]
Risk Management Assets
Risk Management Assets	[8]	3,900,000	[7]		3,900,000	[7]		9,700,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	7,500,000	[7]		7,500,000	[7]		24,700,000	[9]
Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[8]	571,500,000	[7]		571,500,000	[7]		736,900,000	[9]
Risk Management Liabilities	[8]	574,800,000	[7]		574,800,000	[7]		783,800,000	[9]
Risk Management Assets
Risk Management Assets	[8]	571,500,000	[7]		571,500,000	[7]		736,900,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	574,800,000	[7]		574,800,000	[7]		783,800,000	[9]
Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[8]	307,200,000	[7]		307,200,000	[7]		274,300,000	[9]
Risk Management Liabilities	[8]	133,600,000	[7]		133,600,000	[7]		154,100,000	[9]
Risk Management Assets
Risk Management Assets	[8]	307,200,000	[7]		307,200,000	[7]		274,300,000	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	133,600,000	[7]		133,600,000	[7]		154,100,000	[9]
Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[8]	(484,100,000)	[7]		(484,100,000)	[7]		(617,000,000.0)	[9]
Risk Management Liabilities	[8]	(456,500,000)	[7]		(456,500,000)	[7]		(600,300,000)	[9]
Risk Management Assets
Risk Management Assets	[8]	(484,100,000)	[7]		(484,100,000)	[7]		(617,000,000.0)	[9]
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(456,500,000)	[7]		(456,500,000)	[7]		(600,300,000)	[9]
Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets		199,900,000			199,900,000			225,500,000
Risk Management Liabilities		130,400,000			130,400,000			144,900,000
Risk Management Assets
Risk Management Assets		199,900,000			199,900,000			225,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		130,400,000			130,400,000			144,900,000
Energy Contracts [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	45.50			45.50			45.05
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	45.50			45.50			45.05
Energy Contracts [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	0.46			0.46			5.21
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	0.46			0.46			5.21
Energy Contracts [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	121.80			121.80			153.77
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	121.80			121.80			153.77
Natural Gas Contracts [Member] | Level 3 [Member]
Risk Management Assets								0
Risk Management Liabilities								500,000
Risk Management Assets
Risk Management Assets								0
Liabilities, Fair Value Disclosure
Risk Management Liabilities								500,000
Natural Gas Contracts [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[11],[12]							3.11
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[11],[12]							3.11
Natural Gas Contracts [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[12]							3.11
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]							3.11
Natural Gas Contracts [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[12]							3.11
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]							3.11
FTRs [Member] | Level 3 [Member]
Risk Management Assets		127,400,000			127,400,000			68,600,000
Risk Management Liabilities		3,800,000			3,800,000			9,300,000
Risk Management Assets
Risk Management Assets		127,400,000			127,400,000			68,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		3,800,000			3,800,000			9,300,000
FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.20			0.20			0
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	0.20			0.20			0
FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(41.91)			(41.91)			(25.45)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(41.91)			(41.91)			(25.45)
FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	24.96			24.96			17.07
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	24.96			24.96			17.07
Commodity Hedges [Member]
Risk Management Assets	[8]	96,500,000			96,500,000			134,800,000
Risk Management Liabilities	[8]	1,600,000			1,600,000			1,700,000
Risk Management Assets
Risk Management Assets	[8]	96,500,000			96,500,000			134,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	1,600,000			1,600,000			1,700,000
Commodity Hedges [Member] | Level 1 [Member]
Risk Management Assets	[8]	0			0			0
Risk Management Liabilities	[8]	0			0			0
Risk Management Assets
Risk Management Assets	[8]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0			0
Commodity Hedges [Member] | Level 2 [Member]
Risk Management Assets	[8]	83,900,000			83,900,000			123,500,000
Risk Management Liabilities	[8]	8,500,000			8,500,000			9,600,000
Risk Management Assets
Risk Management Assets	[8]	83,900,000			83,900,000			123,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	8,500,000			8,500,000			9,600,000
Commodity Hedges [Member] | Level 3 [Member]
Risk Management Assets	[8]	20,100,000			20,100,000			19,800,000
Risk Management Liabilities	[8]	600,000			600,000			600,000
Risk Management Assets
Risk Management Assets	[8]	20,100,000			20,100,000			19,800,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	600,000			600,000			600,000
Commodity Hedges [Member] | Other [Member]
Risk Management Assets	[8]	(7,500,000)			(7,500,000)			(8,500,000)
Risk Management Liabilities	[8]	(7,500,000)			(7,500,000)			(8,500,000)
Risk Management Assets
Risk Management Assets	[8]	(7,500,000)			(7,500,000)			(8,500,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(7,500,000)			(7,500,000)			(8,500,000)
Interest Rate [Member]
Risk Management Assets		0			0
Risk Management Liabilities		10,900,000			10,900,000			9,000,000.0
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		10,900,000			10,900,000			9,000,000.0
Interest Rate [Member] | Level 1 [Member]
Risk Management Assets		0			0
Risk Management Liabilities		0			0			0
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			0
Interest Rate [Member] | Level 2 [Member]
Risk Management Assets		0			0
Risk Management Liabilities		10,900,000			10,900,000			9,000,000.0
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		10,900,000			10,900,000			9,000,000.0
Interest Rate [Member] | Level 3 [Member]
Risk Management Assets		0			0
Risk Management Liabilities		0			0			0
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			0
Interest Rate [Member] | Other [Member]
Risk Management Assets		0			0
Risk Management Liabilities		0			0			0
Risk Management Assets
Risk Management Assets		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			0
Fair Value Hedges [Member]
Risk Management Liabilities		81,700,000			81,700,000			98,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		81,700,000			81,700,000			98,400,000
Fair Value Hedges [Member] | Level 1 [Member]
Risk Management Liabilities		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			0
Fair Value Hedges [Member] | Level 2 [Member]
Risk Management Liabilities		81,700,000			81,700,000			98,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		81,700,000			81,700,000			98,400,000
Fair Value Hedges [Member] | Level 3 [Member]
Risk Management Liabilities		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			0
Fair Value Hedges [Member] | Other [Member]
Risk Management Liabilities		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0			0
AEP Texas Inc. [Member]
Risk Management Liabilities								2,700,000
Assets, Fair Value Disclosure
Cash and Cash Equivalents		45,100,000			45,100,000			34,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities								2,700,000
AEP Texas Inc. [Member] | Level 1 [Member]
Risk Management Liabilities								0
Assets, Fair Value Disclosure
Cash and Cash Equivalents		45,100,000			45,100,000			34,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities								0
AEP Texas Inc. [Member] | Level 2 [Member]
Risk Management Liabilities								2,900,000
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities								2,900,000
AEP Texas Inc. [Member] | Level 3 [Member]
Risk Management Liabilities								0
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities								0
AEP Texas Inc. [Member] | Other [Member]
Risk Management Liabilities								(200,000)
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities								(200,000)
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member]
Risk Management Liabilities	[8]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0			0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Liabilities	[8]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0			0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Liabilities	[8]	(600,000)			(600,000)			200,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(600,000)			(600,000)			200,000
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Liabilities	[8]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0			0
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Liabilities	[8]	600,000			600,000			(200,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	600,000			600,000			(200,000)
AEP Texas Inc. [Member] | Interest Rate [Member]
Risk Management Liabilities								2,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities								2,700,000
AEP Texas Inc. [Member] | Interest Rate [Member] | Level 1 [Member]
Risk Management Liabilities								0
Liabilities, Fair Value Disclosure
Risk Management Liabilities								0
AEP Texas Inc. [Member] | Interest Rate [Member] | Level 2 [Member]
Risk Management Liabilities								2,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities								2,700,000
AEP Texas Inc. [Member] | Interest Rate [Member] | Level 3 [Member]
Risk Management Liabilities								0
Liabilities, Fair Value Disclosure
Risk Management Liabilities								0
AEP Texas Inc. [Member] | Interest Rate [Member] | Other [Member]
Risk Management Liabilities								0
Liabilities, Fair Value Disclosure
Risk Management Liabilities								0
Appalachian Power Co [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		8,300,000			8,300,000			14,900,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		(55,400,000)			(55,400,000)			(37,300,000)
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		67,800,000		39,400,000	22,400,000		69,100,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	13,400,000		10,000,000.0	24,100,000		(47,000,000.0)
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0	0		0
Settlements		(26,900,000)		(16,500,000)	(46,500,000)		(22,100,000)
Transfers into Level 3	[4],[5]	0			0		0
Transfers out of Level 3	[5]	0		100,000	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	(7,100,000)		12,100,000	47,200,000		45,100,000
Ending Balance		47,200,000		45,100,000	47,200,000		45,100,000
Appalachian Power Co [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		8,300,000			8,300,000			14,900,000
Spent Nuclear Fuel and Decommissioning Trusts
Total Assets		(8,300,000)			(8,300,000)			(14,900,000)
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		(7,300,000)			(7,300,000)			(1,100,000)
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		(47,500,000)			(47,500,000)			(23,500,000)
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		(7,700,000)			(7,700,000)			(2,200,000)
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[8]	47,100,000			47,100,000			22,400,000
Risk Management Liabilities	[8]	13,500,000			13,500,000			22,500,000
Risk Management Assets
Risk Management Assets	[8]	47,100,000			47,100,000			22,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	13,500,000			13,500,000			22,500,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[8]	0			0			0
Risk Management Liabilities	[8]	0			0			0
Risk Management Assets
Risk Management Assets	[8]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0			0
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[8]	7,300,000			7,300,000			1,100,000
Risk Management Liabilities	[8]	21,900,000			21,900,000			24,000,000.0
Risk Management Assets
Risk Management Assets	[8]	7,300,000			7,300,000			1,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	21,900,000			21,900,000			24,000,000.0
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[8]	47,500,000			47,500,000			23,500,000
Risk Management Liabilities	[8]	300,000			300,000			1,100,000
Risk Management Assets
Risk Management Assets	[8]	47,500,000			47,500,000			23,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	300,000			300,000			1,100,000
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[8]	(7,700,000)			(7,700,000)			(2,200,000)
Risk Management Liabilities	[8]	(8,700,000)			(8,700,000)			(2,600,000)
Risk Management Assets
Risk Management Assets	[8]	(7,700,000)			(7,700,000)			(2,200,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(8,700,000)			(8,700,000)			(2,600,000)
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets		47,500,000			47,500,000			23,500,000
Risk Management Liabilities		300,000			300,000			1,100,000
Risk Management Assets
Risk Management Assets		47,500,000			47,500,000			23,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		300,000			300,000			1,100,000
Appalachian Power Co [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	1.30			1.30			1.36
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	1.30			1.30			1.36
Appalachian Power Co [Member] | FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(0.06)			(0.06)			(1.04)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(0.06)			(0.06)			(1.04)
Appalachian Power Co [Member] | FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	9.63			9.63			6.45
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	9.63			9.63			6.45
Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		4,425,800,000			4,425,800,000			3,860,200,000
Total Assets		(4,447,500,000)			(4,447,500,000)			(3,899,800,000)
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		14,500,000		6,800,000	2,800,000		4,600,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	2,900,000		2,300,000	7,300,000		(1,700,000)
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0	0		0
Settlements		(7,900,000)		(3,700,000)	(10,000,000.0)		(2,900,000)
Transfers into Level 3	[4],[5]	0			0		0
Transfers out of Level 3	[5]	0		(100,000)	0		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	(200,000)		1,300,000	9,200,000		6,600,000
Ending Balance		9,300,000		6,600,000	9,300,000		6,600,000
Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		2,827,400,000			2,827,400,000			2,444,400,000
Total Assets		(2,827,400,000)			(2,827,400,000)			(2,444,400,000)
Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,587,800,000			1,587,800,000			1,406,800,000
Total Assets		(1,600,500,000)			(1,600,500,000)			(1,444,200,000)
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		(10,000,000.0)			(10,000,000.0)			(4,500,000)
Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		10,600,000			10,600,000			9,000,000.0
Total Assets		(9,600,000)			(9,600,000)			(6,700,000)
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[8]	21,700,000			21,700,000			39,600,000
Risk Management Liabilities	[8]	400,000			400,000			2,000,000.0
Risk Management Assets
Risk Management Assets	[8]	21,700,000			21,700,000			39,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	400,000			400,000			2,000,000.0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[8]	0			0			0
Risk Management Liabilities	[8]	0			0			0
Risk Management Assets
Risk Management Assets	[8]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0			0
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[8]	12,700,000			12,700,000			37,400,000
Risk Management Liabilities	[8]	900,000			900,000			3,700,000
Risk Management Assets
Risk Management Assets	[8]	12,700,000			12,700,000			37,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	900,000			900,000			3,700,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[8]	10,000,000.0			10,000,000.0			4,500,000
Risk Management Liabilities	[8]	700,000			700,000			1,700,000
Risk Management Assets
Risk Management Assets	[8]	10,000,000.0			10,000,000.0			4,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	700,000			700,000			1,700,000
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[8]	(1,000,000.0)			(1,000,000.0)			(2,300,000)
Risk Management Liabilities	[8]	(1,200,000)			(1,200,000)			(3,400,000)
Risk Management Assets
Risk Management Assets	[8]	(1,000,000.0)			(1,000,000.0)			(2,300,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(1,200,000)			(1,200,000)			(3,400,000)
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets		10,000,000.0			10,000,000.0			4,500,000
Risk Management Liabilities		700,000			700,000			1,700,000
Risk Management Assets
Risk Management Assets		10,000,000.0			10,000,000.0			4,500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		700,000			700,000			1,700,000
Indiana Michigan Power Co [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	1.21			1.21			0.85
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	1.21			1.21			0.85
Indiana Michigan Power Co [Member] | FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(5.00)			(5.00)			(1.48)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(5.00)			(5.00)			(1.48)
Indiana Michigan Power Co [Member] | FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	9.63			9.63			8.40
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	9.63			9.63			8.40
Ohio Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		(43,200,000)		(54,000,000.0)	(50,600,000)		(40,000,000.0)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	(100,000)		0	(900,000)		(2,400,000)
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0	0		0
Settlements		1,000,000.0		1,100,000	6,000,000.0		3,500,000
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]	(9,300,000)		1,300,000	(6,100,000)		(12,700,000)
Ending Balance		(51,600,000)		(51,600,000)	(51,600,000)		(51,600,000)
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Liabilities		51,600,000	[8]		51,600,000	[8]		50,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		51,600,000	[8]		51,600,000	[8]		50,700,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Liabilities		0	[8]		0	[8]		0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0	[8]		0	[8]		0
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Liabilities		400,000	[8]		400,000	[8]		200,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		400,000	[8]		400,000	[8]		200,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Liabilities		51,600,000	[8]		51,600,000	[8]		50,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		51,600,000	[8]		51,600,000	[8]		50,600,000
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Liabilities	[8]	(400,000)			(400,000)			(100,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(400,000)			(400,000)			(100,000)
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
Risk Management Assets		0			0			0
Risk Management Liabilities		51,600,000			51,600,000			50,600,000
Risk Management Assets
Risk Management Assets		0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		51,600,000			51,600,000			50,600,000
Ohio Power Co [Member] | Energy Contracts [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	41.34			41.34			42.85
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	41.34			41.34			42.85
Ohio Power Co [Member] | Energy Contracts [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	19.94			19.94			22.92
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	19.94			19.94			22.92
Ohio Power Co [Member] | Energy Contracts [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	68.22			68.22			67.53
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	68.22			68.22			67.53
Public Service Co Of Oklahoma [Member]
Risk Management Liabilities		22,400,000			22,400,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		22,400,000			22,400,000
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		49,400,000		43,100,000	18,600,000		23,700,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	23,200,000		14,200,000	26,200,000		3,500,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0	0		0
Settlements		(46,300,000)		(30,500,000)	(44,800,000)		(27,200,000)
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]	2,100,000		400,000	28,400,000		27,200,000
Ending Balance		28,400,000		27,200,000	28,400,000		27,200,000
Public Service Co Of Oklahoma [Member] | Level 1 [Member]
Risk Management Liabilities		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Public Service Co Of Oklahoma [Member] | Level 2 [Member]
Risk Management Liabilities		23,100,000			23,100,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		23,100,000			23,100,000
Public Service Co Of Oklahoma [Member] | Level 3 [Member]
Risk Management Liabilities		200,000			200,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		200,000			200,000
Public Service Co Of Oklahoma [Member] | Other [Member]
Risk Management Liabilities		(900,000)			(900,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(900,000)			(900,000)
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[8]	28,500,000			28,500,000			19,000,000.0
Risk Management Liabilities	[8]	22,400,000			22,400,000			29,900,000
Risk Management Assets
Risk Management Assets	[8]	28,500,000			28,500,000			19,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	22,400,000			22,400,000			29,900,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[8]	0			0			0
Risk Management Liabilities	[8]	0			0			0
Risk Management Assets
Risk Management Assets	[8]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0			0
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[8]	600,000			600,000			0
Risk Management Liabilities	[8]	12,200,000			12,200,000			29,600,000
Risk Management Assets
Risk Management Assets	[8]	600,000			600,000			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	12,200,000			12,200,000			29,600,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[8]	28,600,000			28,600,000			19,700,000
Risk Management Liabilities	[8]	200,000			200,000			1,100,000
Risk Management Assets
Risk Management Assets	[8]	28,600,000			28,600,000			19,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	200,000			200,000			1,100,000
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[8]	(700,000)			(700,000)			(700,000)
Risk Management Liabilities	[8]	10,000,000.0			10,000,000.0			(800,000)
Risk Management Assets
Risk Management Assets	[8]	(700,000)			(700,000)			(700,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	10,000,000.0			10,000,000.0			(800,000)
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets		28,600,000			28,600,000			19,700,000
Risk Management Liabilities		200,000			200,000			1,100,000
Risk Management Assets
Risk Management Assets		28,600,000			28,600,000			19,700,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		200,000			200,000			1,100,000
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(3.82)			(3.82)			(4.33)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(3.82)			(3.82)			(4.33)
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(41.91)			(41.91)			(25.45)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(41.91)			(41.91)			(25.45)
Public Service Co Of Oklahoma [Member] | FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	5.93			5.93			4.80
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	5.93			5.93			4.80
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member]
Risk Management Liabilities		(10,900,000)			(10,900,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(10,900,000)			(10,900,000)
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] | Level 1 [Member]
Risk Management Liabilities		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] | Level 2 [Member]
Risk Management Liabilities		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] | Level 3 [Member]
Risk Management Liabilities		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] | Other [Member]
Risk Management Liabilities		(10,900,000)			(10,900,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities		(10,900,000)			(10,900,000)
Public Service Co Of Oklahoma [Member] | Interest Rate [Member]
Risk Management Liabilities		10,900,000			10,900,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		10,900,000			10,900,000
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Level 1 [Member]
Risk Management Liabilities		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Level 2 [Member]
Risk Management Liabilities		10,900,000			10,900,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities		10,900,000			10,900,000
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Level 3 [Member]
Risk Management Liabilities		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Other [Member]
Risk Management Liabilities		0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		0			0
Southwestern Electric Power Co [Member]
Changes in the Fair Value of Net Trading Derivatives and other investments
Beginning Balance		38,100,000		26,000,000.0	11,100,000		14,200,000
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1],[2]	21,200,000		14,000,000.0	23,600,000		5,900,000
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	[2]	0		0	0		0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	[3]	0		0	0		0
Settlements		(37,700,000)		(24,800,000)	(36,000,000.0)		(20,000,000.0)
Transfers into Level 3	[4],[5]	0			0		0
Transfers out of Level 3	[5]	0		0	500,000		0
Changes in Fair Value Allocated to Regulated Jurisdiction	[6]	2,100,000		1,300,000	24,500,000		16,400,000
Ending Balance		23,700,000		$ 16,500,000	23,700,000		$ 16,500,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member]
Risk Management Assets	[8]	24,100,000			24,100,000			11,600,000
Risk Management Liabilities	[8]	4,800,000			4,800,000			15,600,000
Risk Management Assets
Risk Management Assets	[8]	24,100,000			24,100,000			11,600,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	4,800,000			4,800,000			15,600,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets	[8]	0			0			0
Risk Management Liabilities	[8]	0			0			0
Risk Management Assets
Risk Management Assets	[8]	0			0			0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	0			0			0
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets	[8]	300,000			300,000			500,000
Risk Management Liabilities	[8]	5,000,000.0			5,000,000.0			15,700,000
Risk Management Assets
Risk Management Assets	[8]	300,000			300,000			500,000
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	5,000,000.0			5,000,000.0			15,700,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets	[8]	24,300,000			24,300,000			12,000,000.0
Risk Management Liabilities	[8]	600,000			600,000			900,000
Risk Management Assets
Risk Management Assets	[8]	24,300,000			24,300,000			12,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	600,000			600,000			900,000
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member]
Risk Management Assets	[8]	(500,000)			(500,000)			(900,000)
Risk Management Liabilities	[8]	(800,000)			(800,000)			(1,000,000.0)
Risk Management Assets
Risk Management Assets	[8]	(500,000)			(500,000)			(900,000)
Liabilities, Fair Value Disclosure
Risk Management Liabilities	[8]	(800,000)			(800,000)			(1,000,000.0)
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Level 3 [Member]
Risk Management Assets								0
Risk Management Liabilities								500,000
Risk Management Assets
Risk Management Assets								0
Liabilities, Fair Value Disclosure
Risk Management Liabilities								500,000
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[11],[12]							3.11
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[11],[12]							3.11
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[12]							3.11
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]							3.11
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[12]							3.11
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[12]							3.11
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member]
Risk Management Assets		24,300,000			24,300,000			12,000,000.0
Risk Management Liabilities		600,000			600,000			400,000
Risk Management Assets
Risk Management Assets		24,300,000			24,300,000			12,000,000.0
Liabilities, Fair Value Disclosure
Risk Management Liabilities		600,000			600,000			400,000
Southwestern Electric Power Co [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(3.82)			(3.82)			(4.33)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10],[11]	(3.82)			(3.82)			(4.33)
Southwestern Electric Power Co [Member] | FTRs [Member] | Low [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	(41.91)			(41.91)			(25.45)
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	(41.91)			(41.91)			(25.45)
Southwestern Electric Power Co [Member] | FTRs [Member] | High [Member] | Level 3 [Member]
Fair Value Significant Unobservable Input Price Per Unit	[10]	5.93			5.93			4.80
Level 3 Quantitative Information
Fair Value Significant Unobservable Input Price Per Unit	[10]	5.93			5.93			4.80
Cash [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		53,400,000			53,400,000			48,900,000
Other Short-term Investments	[13]	53,400,000			53,400,000			48,900,000
Cash [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		53,400,000			53,400,000			48,900,000
Cash [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Cash [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Cash [Member] | Other [Member]
Assets, Fair Value Disclosure
Cash and Cash Equivalents		0			0			0
Other Cash Deposits [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		17,000,000.0			17,000,000.0			13,900,000
Other Cash Deposits [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Other Cash Deposits [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Other Cash Deposits [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Other Cash Deposits [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[14]	17,000,000.0			17,000,000.0			13,900,000
Mutual Funds Fixed Income [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[15]	164,600,000			164,600,000			159,700,000
Mutual Funds Fixed Income [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		164,600,000			164,600,000			159,700,000
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 Fixed Income [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments		0			0			0
Mutual Funds Equity [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	47,000,000.0			47,000,000.0			40,700,000
Mutual Funds Equity [Member] | Level 1 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	47,000,000.0			47,000,000.0			40,700,000
Mutual Funds Equity [Member] | Level 2 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	0			0			0
Mutual Funds Equity [Member] | Level 3 [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	0			0			0
Mutual Funds Equity [Member] | Other [Member]
Assets, Fair Value Disclosure
Other Short-term Investments	[16]	0			0			0
Cash and Cash Equivalents [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	26,200,000			26,200,000			16,800,000
Cash and Cash Equivalents [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	15,600,000			15,600,000			7,800,000
Cash and Cash Equivalents [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0			0
Cash and Cash Equivalents [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	0			0			0
Cash and Cash Equivalents [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	10,600,000			10,600,000			9,000,000.0
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	26,200,000			26,200,000			16,800,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	15,600,000			15,600,000			7,800,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	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	[17]	0			0			0
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[17]	10,600,000			10,600,000			9,000,000.0
US Government Agencies Debt Securities [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,370,500,000			1,370,500,000			1,273,000,000
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		1,370,500,000			1,370,500,000			1,273,000,000
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] | 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]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,370,500,000			1,370,500,000			1,273,000,000
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		1,370,500,000			1,370,500,000			1,273,000,000
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
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
Corporate Debt [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		215,600,000			215,600,000			132,100,000
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		215,600,000			215,600,000			132,100,000
Corporate Debt [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		0			0			0
Corporate Debt [Member] | 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]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		215,600,000			215,600,000			132,100,000
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		215,600,000			215,600,000			132,100,000
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
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
State and Local Jurisdiction [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,700,000			1,700,000			1,700,000
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		1,700,000			1,700,000			1,700,000
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] | 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]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,700,000			1,700,000			1,700,000
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		1,700,000			1,700,000			1,700,000
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
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
Fixed Income Funds [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,587,800,000			1,587,800,000			1,406,800,000
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		1,587,800,000			1,587,800,000			1,406,800,000
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] | 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]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts		1,587,800,000			1,587,800,000			1,406,800,000
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		1,587,800,000			1,587,800,000			1,406,800,000
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
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
Domestic [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,811,800,000			2,811,800,000			2,436,600,000
Domestic [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,811,800,000			2,811,800,000			2,436,600,000
Domestic [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	0			0			0
Domestic [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	0			0			0
Domestic [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	0			0			0
Domestic [Member] | Indiana Michigan Power Co [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,811,800,000			2,811,800,000			2,436,600,000
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	2,811,800,000			2,811,800,000			2,436,600,000
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	0			0			0
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	0			0			0
Domestic [Member] | Indiana Michigan Power Co [Member] | Other [Member]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	[16]	$ 0			$ 0			$ 0

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

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

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

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

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

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

[7] The September 30, 2024 maturities of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), were as follows: Level 1 matures $(1) million in 2024 and $(2) million in periods 2025-2027; Level 2 matures $(23) million in 2024, $15 million in periods 2025-2027 and $5 million in periods 2028-2029; Level 3 matures $45 million in 2024, $129 million in periods 2025-2027, $17 million in periods 2028-2029 and $(18) million in periods 2030-2032.  Risk management commodity contracts are substantially comprised of power contracts.

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

[9] The December 31, 2023 maturities of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), were as follows: Level 1 matures $(11) million in 2024 and $(4) million in 2025-2027; Level 2 matures $(99) million in 2024, $(44) million in periods 2025-2027, $7 million in periods 2028-2029 and $2 million in periods 2030-2033; Level 3 matures $74 million in 2024, $43 million in periods 2025-2027, $18 million in periods 2028-2029 and $(16) million in periods 2030-2033.  Risk management commodity contracts are substantially comprised of power contracts

[10] Represents market prices in dollars per MWh.

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

[12] Represents market prices in dollars per MMBtu.

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

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

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

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

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