Derivatives and Hedging (Details) gal in Millions, MWh in Millions, MMBTU in Millions		3 Months Ended			12 Months Ended
		Mar. 31, 2024 USD ($) MMBTU MWh gal		Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) MMBTU MWh gal
Cash Collateral Netting
Cash Collateral Received Netted Against Risk Management Assets		$ 86,000,000			$ 46,000,000
Fair Value of Derivative Instruments
Current Risk Management Assets		152,700,000			217,500,000
Long-term Risk Management Assets		314,400,000			321,200,000
Total Assets		467,100,000			538,700,000
Current Risk Management Liabilities		184,400,000			229,600,000
Long-term Risk Management Liabilities		279,500,000			241,800,000
Total Liabilities		463,900,000			471,400,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(3,100,000)		$ (178,200,000)
Carrying Amount of Hedged Asset (Liability)	[1],[2]	(860,200,000)			(878,200,000)
Cumulative Fair Value Hedging Adjustment in the Carrying Amount of the Hedged Asset (Liability)	[1],[2]	86,700,000			68,400,000
Gain (Loss) on Hedging Instruments
Gain (Loss) on Fair Value Hedging Instruments	[3]	(16,400,000)		6,900,000
Gain (Loss) on Fair Value Portion of Long Term Debt	[3]	16,400,000		(6,900,000)
Collateral Triggering Events [Abstract]
Fair Value Of Derivative Liabilities Subject To Cross Acceleration Provisions		116,000,000			107,000,000
Fair Value Of Derivative Liabilities Subject To Cross Default Provisions		235,000,000			242,000,000
Derivatives and Hedging (Textuals) [Abstract]
Hedged Liability, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)		(28,000,000)			(30,000,000)
AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Total Assets		2,500,000
Total Liabilities		100,000			2,700,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		400,000		(400,000)
Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		8,700,000			22,400,000
Current Risk Management Liabilities		18,400,000			15,900,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		14,000,000.0		(32,700,000)
Collateral Triggering Events [Abstract]
Fair Value Of Derivative Liabilities Subject To Cross Default Provisions		16,000,000			22,000,000
Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		11,200,000			27,800,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(25,200,000)		(4,600,000)
Ohio Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Liabilities		6,000,000.0			6,800,000
Long-term Risk Management Liabilities		35,000,000.0			43,900,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		8,600,000		(12,300,000)
Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		7,900,000			19,000,000.0
Current Risk Management Liabilities		28,500,000			28,900,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		17,100,000		16,800,000
Collateral Triggering Events [Abstract]
Fair Value Of Derivative Liabilities Subject To Cross Default Provisions		31,000,000			29,000,000
Southwestern Electric Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		19,900,000		10,400,000
Collateral Triggering Events [Abstract]
Fair Value Of Derivative Liabilities Subject To Cross Default Provisions		10,000,000			15,000,000
Risk Management Contracts [Member]
Fair Value of Derivative Instruments
Total Assets	[5]	346,900,000	[4]		403,900,000	[6]
Total Liabilities	[5]	346,200,000	[4]		362,300,000	[6]
Risk Management Contracts [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Total Assets	[5]	2,500,000
Total Liabilities	[5]	100,000			0
Risk Management Contracts [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[5]	8,700,000			22,400,000
Total Liabilities	[5]	20,500,000			22,500,000
Risk Management Contracts [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[5]	11,200,000			39,600,000
Total Liabilities	[5]	700,000			2,000,000.0
Risk Management Contracts [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[5]	100,000
Total Liabilities		41,000,000.0	[5]		50,700,000
Risk Management Contracts [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Total Assets	[5]	7,900,000			19,000,000.0
Total Liabilities	[5]	31,300,000			29,900,000
Risk Management Contracts [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[5]	5,300,000			11,600,000
Total Liabilities	[5]	11,100,000			15,600,000
Commodity [Member]
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		87,200,000			104,900,000
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		$ 24,000,000.0			38,300,000
Derivatives and Hedging (Textuals) [Abstract]
Maximum Term for Exposure to Variability of Future Cash Flows		84 months
Cross Acceleration Provisions Maximum Third Party Obligation Amount		$ 50,000,000
Cross Default Provisions Maximum Third Party Obligation Amount		50,000,000
Commodity [Member] | AEP Texas Inc. [Member]
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		0			0
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		0			0
Commodity [Member] | Appalachian Power Co [Member]
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		0			0
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		0			0
Commodity [Member] | Indiana Michigan Power Co [Member]
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		0			0
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		0			0
Commodity [Member] | Public Service Co Of Oklahoma [Member]
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		0			0
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		0			0
Commodity [Member] | Southwestern Electric Power Co [Member]
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		0			0
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		0			0
Commodity [Member] | Risk Management Contracts [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		436,200,000			555,100,000
Long-term Risk Management Assets		525,000,000.0			468,800,000
Current Risk Management Liabilities		456,900,000			588,000,000.0
Long-term Risk Management Liabilities		430,000,000.0			377,600,000
Commodity [Member] | Risk Management Contracts [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		200,000			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			200,000
Long-term Risk Management Liabilities		0			0
Commodity [Member] | Risk Management Contracts [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		9,900,000			24,600,000
Long-term Risk Management Assets		1,200,000			300,000
Current Risk Management Liabilities		21,000,000.0			18,500,000
Long-term Risk Management Liabilities		3,300,000			6,900,000
Commodity [Member] | Risk Management Contracts [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		15,500,000			30,100,000
Long-term Risk Management Assets		0			12,000,000.0
Current Risk Management Liabilities		9,000,000.0			5,400,000
Long-term Risk Management Liabilities		0			200,000
Commodity [Member] | Risk Management Contracts [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		100,000			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		6,000,000.0			6,900,000
Long-term Risk Management Liabilities		35,000,000.0			43,900,000
Commodity [Member] | Risk Management Contracts [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		8,500,000			19,700,000
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		29,100,000			29,700,000
Long-term Risk Management Liabilities		2,800,000			1,000,000.0
Commodity [Member] | Risk Management Contracts [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		5,500,000			12,000,000.0
Long-term Risk Management Assets		0			500,000
Current Risk Management Liabilities		9,500,000			14,900,000
Long-term Risk Management Liabilities		1,800,000			1,700,000
Commodity [Member] | Hedging Contracts [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		35,400,000			56,700,000
Long-term Risk Management Assets		81,000,000.0			86,800,000
Current Risk Management Liabilities		5,100,000			8,200,000
Long-term Risk Management Liabilities		600,000			2,200,000
Commodity [Member] | Hedging Contracts [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			0
Long-term Risk Management Liabilities		0			0
Commodity [Member] | Hedging Contracts [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			0
Long-term Risk Management Liabilities		0			0
Commodity [Member] | Hedging Contracts [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			0
Long-term Risk Management Liabilities		0			0
Commodity [Member] | Hedging Contracts [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			0
Long-term Risk Management Liabilities		0			0
Commodity [Member] | Hedging Contracts [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			0
Long-term Risk Management Liabilities		0			0
Commodity [Member] | Hedging Contracts [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			0
Long-term Risk Management Liabilities		0			0
Interest Rate [Member]
Commodity:
Derivative, Notional Amount		1,500,000,000			1,300,000,000
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		3,400,000			(8,100,000)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		3,600,000			3,200,000
Interest Rate [Member] | AEP Texas Inc. [Member]
Commodity:
Derivative, Notional Amount		150,000,000.0			150,000,000.0
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		4,400,000			500,000
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		500,000			200,000
Interest Rate [Member] | Appalachian Power Co [Member]
Commodity:
Derivative, Notional Amount		0			0
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		5,700,000			5,900,000
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		800,000			800,000
Interest Rate [Member] | Indiana Michigan Power Co [Member]
Commodity:
Derivative, Notional Amount		0			0
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		(5,400,000)			(5,500,000)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		(400,000)			(400,000)
Interest Rate [Member] | Ohio Power Co [Member]
Commodity:
Derivative, Notional Amount		0			0
Interest Rate [Member] | Public Service Co Of Oklahoma [Member]
Commodity:
Derivative, Notional Amount		0			0
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		(200,000)			(200,000)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		0			0
Interest Rate [Member] | Southwestern Electric Power Co [Member]
Commodity:
Derivative, Notional Amount		0			0
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		1,200,000			1,300,000
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		300,000			300,000
Interest Rate [Member] | Hedging Contracts [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		8,300,000			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		46,100,000			50,500,000
Long-term Risk Management Liabilities		70,400,000			56,900,000
Interest Rate [Member] | Hedging Contracts [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		2,300,000			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		100,000			2,700,000
Long-term Risk Management Liabilities		0			0
Interest Rate [Member] | Hedging Contracts [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			0
Long-term Risk Management Liabilities		0			0
Interest Rate [Member] | Hedging Contracts [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			0
Long-term Risk Management Liabilities		0			0
Interest Rate [Member] | Hedging Contracts [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			0
Long-term Risk Management Liabilities		0			0
Interest Rate [Member] | Hedging Contracts [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			0
Long-term Risk Management Liabilities		0			0
Interest Rate [Member] | Hedging Contracts [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			0
Long-term Risk Management Liabilities		0			0
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		479,900,000			611,800,000
Long-term Risk Management Assets		606,000,000.0			555,600,000
Total Assets		1,085,900,000			1,167,400,000
Current Risk Management Liabilities		508,100,000			646,700,000
Long-term Risk Management Liabilities		501,000,000.0			436,700,000
Total Liabilities		1,009,100,000			1,083,400,000
Total MTM Derivative Contract Net Assets (Liabilities)		76,800,000			84,000,000.0
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		2,500,000			0
Long-term Risk Management Assets		0			0
Total Assets		2,500,000			0
Current Risk Management Liabilities		100,000			2,900,000
Long-term Risk Management Liabilities		0			0
Total Liabilities		100,000			2,900,000
Total MTM Derivative Contract Net Assets (Liabilities)		2,400,000			(2,900,000)
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		9,900,000			24,600,000
Long-term Risk Management Assets		1,200,000			300,000
Total Assets		11,100,000			24,900,000
Current Risk Management Liabilities		21,000,000.0			18,500,000
Long-term Risk Management Liabilities		3,300,000			6,900,000
Total Liabilities		24,300,000			25,400,000
Total MTM Derivative Contract Net Assets (Liabilities)		(13,200,000)			(500,000)
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		15,500,000			30,100,000
Long-term Risk Management Assets		0			12,000,000.0
Total Assets		15,500,000			42,100,000
Current Risk Management Liabilities		9,000,000.0			5,400,000
Long-term Risk Management Liabilities		0			200,000
Total Liabilities		9,000,000.0			5,600,000
Total MTM Derivative Contract Net Assets (Liabilities)		6,500,000			36,500,000
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		100,000			0
Long-term Risk Management Assets		0			0
Total Assets		100,000			0
Current Risk Management Liabilities		6,000,000.0			6,900,000
Long-term Risk Management Liabilities		35,000,000.0			43,900,000
Total Liabilities		41,000,000.0			50,800,000
Total MTM Derivative Contract Net Assets (Liabilities)		(40,900,000)			(50,800,000)
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		8,500,000			19,700,000
Long-term Risk Management Assets		0			0
Total Assets		8,500,000			19,700,000
Current Risk Management Liabilities		29,100,000			29,700,000
Long-term Risk Management Liabilities		2,800,000			1,000,000.0
Total Liabilities		31,900,000			30,700,000
Total MTM Derivative Contract Net Assets (Liabilities)		(23,400,000)			(11,000,000.0)
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		5,500,000			12,000,000.0
Long-term Risk Management Assets		0			500,000
Total Assets		5,500,000			12,500,000
Current Risk Management Liabilities		9,500,000			14,900,000
Long-term Risk Management Liabilities		1,800,000			1,700,000
Total Liabilities		11,300,000			16,600,000
Total MTM Derivative Contract Net Assets (Liabilities)		(5,800,000)			(4,100,000)
Gross Amounts Offset in the Statement of Financial Position [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		(327,200,000)			(394,300,000)
Long-term Risk Management Assets		(291,600,000)			(234,400,000)
Current Risk Management Liabilities		(323,700,000)			(417,100,000)
Long-term Risk Management Liabilities		(221,500,000)			(194,900,000)
Gross Amounts Offset in the Statement of Financial Position [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			(200,000)
Long-term Risk Management Liabilities		0			0
Gross Amounts Offset in the Statement of Financial Position [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		(1,200,000)			(2,200,000)
Long-term Risk Management Assets		(1,200,000)			(300,000)
Current Risk Management Liabilities		(2,600,000)			(2,600,000)
Long-term Risk Management Liabilities		(1,200,000)			(300,000)
Gross Amounts Offset in the Statement of Financial Position [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		(4,300,000)			(2,300,000)
Long-term Risk Management Assets		0			(200,000)
Current Risk Management Liabilities		(8,300,000)			(3,400,000)
Long-term Risk Management Liabilities		0			(200,000)
Gross Amounts Offset in the Statement of Financial Position [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		0			0
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		0			(100,000)
Long-term Risk Management Liabilities		0			0
Gross Amounts Offset in the Statement of Financial Position [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		(600,000)			(700,000)
Long-term Risk Management Assets		0			0
Current Risk Management Liabilities		(600,000)			(800,000)
Long-term Risk Management Liabilities		0			0
Gross Amounts Offset in the Statement of Financial Position [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		(200,000)			(400,000)
Long-term Risk Management Assets		0			(500,000)
Current Risk Management Liabilities		(200,000)			(500,000)
Long-term Risk Management Liabilities		0			(500,000)
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		152,700,000			217,500,000
Long-term Risk Management Assets		314,400,000			321,200,000
Total Assets		467,100,000			538,700,000
Current Risk Management Liabilities		184,400,000			229,600,000
Long-term Risk Management Liabilities		279,500,000			241,800,000
Total Liabilities		463,900,000			471,400,000
Total MTM Derivative Contract Net Assets (Liabilities)		3,200,000			67,300,000
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		2,500,000			0
Long-term Risk Management Assets		0			0
Total Assets		2,500,000			0
Current Risk Management Liabilities		100,000			2,700,000
Long-term Risk Management Liabilities		0			0
Total Liabilities		100,000			2,700,000
Total MTM Derivative Contract Net Assets (Liabilities)		2,400,000			(2,700,000)
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		8,700,000			22,400,000
Long-term Risk Management Assets		0			0
Total Assets		8,700,000			22,400,000
Current Risk Management Liabilities		18,400,000			15,900,000
Long-term Risk Management Liabilities		2,100,000			6,600,000
Total Liabilities		20,500,000			22,500,000
Total MTM Derivative Contract Net Assets (Liabilities)		(11,800,000)			(100,000)
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		11,200,000			27,800,000
Long-term Risk Management Assets		0			11,800,000
Total Assets		11,200,000			39,600,000
Current Risk Management Liabilities		700,000			2,000,000.0
Long-term Risk Management Liabilities		0			0
Total Liabilities		700,000			2,000,000.0
Total MTM Derivative Contract Net Assets (Liabilities)		10,500,000			37,600,000
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		100,000			0
Long-term Risk Management Assets		0			0
Total Assets		100,000			0
Current Risk Management Liabilities		6,000,000.0			6,800,000
Long-term Risk Management Liabilities		35,000,000.0			43,900,000
Total Liabilities		41,000,000.0			50,700,000
Total MTM Derivative Contract Net Assets (Liabilities)		(40,900,000)			(50,700,000)
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		7,900,000			19,000,000.0
Long-term Risk Management Assets		0			0
Total Assets		7,900,000			19,000,000.0
Current Risk Management Liabilities		28,500,000			28,900,000
Long-term Risk Management Liabilities		2,800,000			1,000,000.0
Total Liabilities		31,300,000			29,900,000
Total MTM Derivative Contract Net Assets (Liabilities)		(23,400,000)			(10,900,000)
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		5,300,000			11,600,000
Long-term Risk Management Assets		0			0
Total Assets		5,300,000			11,600,000
Current Risk Management Liabilities		9,300,000			14,400,000
Long-term Risk Management Liabilities		1,800,000			1,200,000
Total Liabilities		11,100,000			15,600,000
Total MTM Derivative Contract Net Assets (Liabilities)		$ (5,800,000)			$ (4,000,000.0)
Power [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		233.5			246.8
Power [Member] | AEP Texas Inc. [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		0.0			0.0
Power [Member] | Appalachian Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		7.0			16.8
Power [Member] | Indiana Michigan Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		3.4			5.9
Power [Member] | Ohio Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		2.2			2.2
Power [Member] | Public Service Co Of Oklahoma [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		2.2			4.1
Power [Member] | Southwestern Electric Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		1.6			2.9
Natural Gas [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		176.8			151.6
Natural Gas [Member] | AEP Texas Inc. [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		0.0			0.0
Natural Gas [Member] | Appalachian Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		43.0			37.3
Natural Gas [Member] | Indiana Michigan Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		0.0			0.0
Natural Gas [Member] | Ohio Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		0.0			0.0
Natural Gas [Member] | Public Service Co Of Oklahoma [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		49.0			34.9
Natural Gas [Member] | Southwestern Electric Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		19.7			17.9
Heating Oil and Gasoline [Member]
Commodity:
Derivative, Volume Notional Amount | gal		7.7			6.5
Heating Oil and Gasoline [Member] | AEP Texas Inc. [Member]
Commodity:
Derivative, Volume Notional Amount | gal		2.0			1.8
Heating Oil and Gasoline [Member] | Appalachian Power Co [Member]
Commodity:
Derivative, Volume Notional Amount | gal		1.1			1.0
Heating Oil and Gasoline [Member] | Indiana Michigan Power Co [Member]
Commodity:
Derivative, Volume Notional Amount | gal		1.2			0.6
Heating Oil and Gasoline [Member] | Ohio Power Co [Member]
Commodity:
Derivative, Volume Notional Amount | gal		1.3			1.2
Heating Oil and Gasoline [Member] | Public Service Co Of Oklahoma [Member]
Commodity:
Derivative, Volume Notional Amount | gal		0.8			0.7
Heating Oil and Gasoline [Member] | Southwestern Electric Power Co [Member]
Commodity:
Derivative, Volume Notional Amount | gal		1.0			0.9
Interest Rate Contract [Member]
Commodity:
Derivative, Notional Amount		$ 69,600,000			$ 80,100,000
Interest Rate Contract [Member] | AEP Texas Inc. [Member]
Commodity:
Derivative, Notional Amount		0			0
Interest Rate Contract [Member] | Appalachian Power Co [Member]
Commodity:
Derivative, Notional Amount		0			0
Interest Rate Contract [Member] | Indiana Michigan Power Co [Member]
Commodity:
Derivative, Notional Amount		0			0
Interest Rate Contract [Member] | Ohio Power Co [Member]
Commodity:
Derivative, Notional Amount		0			0
Interest Rate Contract [Member] | Public Service Co Of Oklahoma [Member]
Commodity:
Derivative, Notional Amount		0			0
Interest Rate Contract [Member] | Southwestern Electric Power Co [Member]
Commodity:
Derivative, Notional Amount		0			$ 0
Vertically Integrated Utilities Revenues [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(25,700,000)		(5,300,000)
Vertically Integrated Utilities Revenues [Member] | AEP Texas Inc. [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Vertically Integrated Utilities Revenues [Member] | Appalachian Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Vertically Integrated Utilities Revenues [Member] | Indiana Michigan Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Vertically Integrated Utilities Revenues [Member] | Ohio Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Vertically Integrated Utilities Revenues [Member] | Public Service Co Of Oklahoma [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Vertically Integrated Utilities Revenues [Member] | Southwestern Electric Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Generation and Marketing Revenues [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(44,700,000)		(147,400,000)
Generation and Marketing Revenues [Member] | AEP Texas Inc. [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Generation and Marketing Revenues [Member] | Appalachian Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Generation and Marketing Revenues [Member] | Indiana Michigan Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Generation and Marketing Revenues [Member] | Ohio Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Generation and Marketing Revenues [Member] | Public Service Co Of Oklahoma [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Generation and Marketing Revenues [Member] | Southwestern Electric Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Electric Generation, Transmission and Distribution Revenues [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Electric Generation, Transmission and Distribution Revenues [Member] | AEP Texas Inc. [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Electric Generation, Transmission and Distribution Revenues [Member] | Appalachian Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		100,000		0
Electric Generation, Transmission and Distribution Revenues [Member] | Indiana Michigan Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(25,800,000)		(5,300,000)
Electric Generation, Transmission and Distribution Revenues [Member] | Ohio Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Electric Generation, Transmission and Distribution Revenues [Member] | Public Service Co Of Oklahoma [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Electric Generation, Transmission and Distribution Revenues [Member] | Southwestern Electric Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		1,000,000.0		700,000
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] | AEP Texas Inc. [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] | Appalachian Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		900,000		600,000
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] | Indiana Michigan Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] | Ohio Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] | Public Service Co Of Oklahoma [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] | Southwestern Electric Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Maintenance Expense [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		100,000		100,000
Maintenance Expense [Member] | AEP Texas Inc. [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Maintenance Expense [Member] | Appalachian Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Maintenance Expense [Member] | Indiana Michigan Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Maintenance Expense [Member] | Ohio Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Maintenance Expense [Member] | Public Service Co Of Oklahoma [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Maintenance Expense [Member] | Southwestern Electric Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		0		0
Regulatory Assets [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	13,500,000		(24,800,000)
Regulatory Assets [Member] | AEP Texas Inc. [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	200,000		(400,000)
Regulatory Assets [Member] | Appalachian Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	(100,000)		(7,100,000)
Regulatory Assets [Member] | Indiana Michigan Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	(1,600,000)		(500,000)
Regulatory Assets [Member] | Ohio Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	8,600,000		(12,300,000)
Regulatory Assets [Member] | Public Service Co Of Oklahoma [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	(1,200,000)		(1,200,000)
Regulatory Assets [Member] | Southwestern Electric Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	4,900,000		(1,500,000)
Regulatory Liabilities [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	52,700,000		(1,500,000)
Regulatory Liabilities [Member] | AEP Texas Inc. [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	200,000		0
Regulatory Liabilities [Member] | Appalachian Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	13,100,000		(26,200,000)
Regulatory Liabilities [Member] | Indiana Michigan Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	2,200,000		1,200,000
Regulatory Liabilities [Member] | Ohio Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	0		0
Regulatory Liabilities [Member] | Public Service Co Of Oklahoma [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	18,300,000		18,000,000.0
Regulatory Liabilities [Member] | Southwestern Electric Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[7]	$ 15,000,000.0		$ 11,900,000

[1] Amounts include $(28) million and $(30) million as of March 31, 2024 and December 31, 2023, respectively, for the fair value hedge adjustment of hedged debt obligations for which hedge accounting has been discontinued.

[2] Amounts included within Noncurrent Liabilities line item Long-term Debt on the Balance Sheet.

[3] Gain (Loss) is included in Interest Expense on the statements of income.

[4] The March 31, 2024 maturities of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), were as follows: Level 1 matures $(14) million in 2024 and $(3) million in periods 2025-2027; Level 2 matures $(65) million in 2024, $51 million in periods 2025-2027 and $5 million in periods 2028-2029; Level 3 matures $34 million in 2024, $55 million in periods 2025-2027, $23 million in periods 2028-2029 and $(12) million in periods 2030-2032.  Risk management commodity contracts are substantially comprised of power contracts.

[5] 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.’’

[6] 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

[7] Represents realized and unrealized gains and losses subject to regulatory accounting treatment recorded as either current or noncurrent on the balance sheets.