Derivatives and Hedging (Details) gal in Millions, MWh in Millions, MMBTU in Millions		12 Months Ended
		Dec. 31, 2020 USD ($) MMBTU MWh gal		Dec. 31, 2019 USD ($) MMBTU MWh gal		Dec. 31, 2018 USD ($)
Change in Fair Value Recognized in AOCI		$ (66,400,000)		$ (69,700,000)		$ 6,600,000
Cash Collateral Netting
Cash Collateral Received Netted Against Risk Management Assets		3,000,000		5,000,000
Cash Collateral Paid Netted Against Risk Management Liabilities		7,000,000		39,000,000
Fair Value of Derivative Instruments
Current Risk Management Assets		94,700,000		172,800,000
Long-term Risk Management Assets		242,200,000		266,600,000
Total Assets		336,900,000		439,400,000
Current Risk Management Liabilities		78,800,000		114,300,000
Long-term Risk Management Liabilities		232,800,000		261,800,000
Total Liabilities		311,600,000		376,100,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		116,900,000		125,000,000.0		291,300,000
Impact of Fair Value Hedges on the Balance Sheet
Carrying Amount of Hedged Asset (Liability)	[1],[2]	(995,900,000)		(510,800,000)
Cumulative Fair Value Hedging Adjustment in the Carrying Amount of the Hedged Asset (Liability)	[1],[2]	(51,700,000)		(14,500,000)
Impact of Cash Flow Hedges on the Balance Sheet
Gain (Loss) on Fair Value Hedging Instruments	[3]	41,100,000		31,900,000		(11,300,000)
Gain (Loss) on Fair Value Portion of Long Term Debt	[3]	(41,100,000)		(31,900,000)		11,300,000
Collateral Triggering Events
Liabilities for Contracts with Cross Default Provisions Prior to Contractural Netting Arrangements		188,400,000		267,300,000
Amount of Cash Collateral Posted		0		3,700,000
Additional Settlement Liability if Cross Default Provision is Triggered		169,200,000		246,700,000
Derivatives and Hedging (Textuals)
Hedged Liability, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)		(53,000,000)		0
Notional Amount of a Discontinued Hedge		500,000,000
Deferred (Gain) Loss on Discontinuation of Fair Value Hedge		57,000,000
AEP Texas Inc. [Member]
Change in Fair Value Recognized in AOCI		2,700,000		1,100,000		(1,000,000.0)
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(1,000,000.0)		300,000		(400,000)
Appalachian Power Co [Member]
Change in Fair Value Recognized in AOCI		7,000,000.0		13,400,000		(3,300,000)
Fair Value of Derivative Instruments
Current Risk Management Assets		22,400,000		39,400,000
Total Assets		22,500,000
Current Risk Management Liabilities		4,600,000		1,900,000
Total Liabilities		4,700,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		21,300,000		4,100,000		141,100,000
Collateral Triggering Events
Liabilities for Contracts with Cross Default Provisions Prior to Contractural Netting Arrangements		4,300,000		2,300,000
Amount of Cash Collateral Posted		0		0
Additional Settlement Liability if Cross Default Provision is Triggered		3,500,000		400,000
Indiana Michigan Power Co [Member]
Change in Fair Value Recognized in AOCI		3,100,000		800,000		(600,000)
Fair Value of Derivative Instruments
Current Risk Management Assets		3,600,000		9,800,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		12,000,000.0		25,200,000		11,700,000
Collateral Triggering Events
Liabilities for Contracts with Cross Default Provisions Prior to Contractural Netting Arrangements		500,000		1,300,000
Amount of Cash Collateral Posted		0		0
Additional Settlement Liability if Cross Default Provision is Triggered		100,000		200,000
Ohio Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Liabilities		8,700,000		7,300,000
Long-term Risk Management Liabilities		101,600,000		96,300,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		5,000,000.0		6,000,000.0		25,600,000
Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		10,300,000		15,800,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		38,600,000		35,600,000		36,600,000
Southwestern Electric Power Co [Member]
Change in Fair Value Recognized in AOCI		3,200,000		3,700,000		(800,000)
Fair Value of Derivative Instruments
Current Risk Management Assets		3,200,000		6,400,000
Current Risk Management Liabilities		700,000		1,900,000
Long-term Risk Management Liabilities		1,000,000.0		3,100,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		21,000,000.0		25,000,000.0		11,200,000
Collateral Triggering Events
Liabilities for Contracts with Cross Default Provisions Prior to Contractural Netting Arrangements		1,800,000		5,100,000
Amount of Cash Collateral Posted		0		0
Additional Settlement Liability if Cross Default Provision is Triggered		1,800,000		5,100,000
Risk Management Contracts [Member]
Fair Value of Derivative Instruments
Total Assets	[4]	322,100,000	[5]	408,800,000	[6]
Total Liabilities	[4]	218,900,000	[5]	239,000,000.0	[6]
Risk Management Contracts [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Total Assets	[4]	0
Risk Management Contracts [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	20,100,000		39,500,000
Total Liabilities	[4],[7]	1,300,000		1,900,000
Risk Management Contracts [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	3,700,000		9,900,000
Total Liabilities	[4],[7]	200,000		500,000
Risk Management Contracts [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	0
Total Liabilities	[4],[7]	110,300,000		103,600,000
Risk Management Contracts [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	10,300,000		15,800,000
Total Liabilities	[4],[7]			0
Risk Management Contracts [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	3,200,000		6,400,000
Total Liabilities	[4],[7]	1,700,000		5,000,000.0
Commodity [Member]
Impact of Cash Flow Hedges on the Balance Sheet
AOCI Gain (Loss) Net of Tax		(60,600,000)		(103,500,000)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		$ (27,100,000)		(51,700,000)
Derivatives and Hedging (Textuals)
Maximum Length of Time Hedged in Price Risk Cash Flow Hedge		123 months
Cross Default Provisions Maximum Third Party Obligation Amount		$ 50,000,000
Commodity [Member] | Risk Management Contracts [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[8]	239,100,000		513,900,000
Long-term Risk Management Assets	[8]	275,900,000		290,800,000
Total Assets	[8]	515,000,000.0		804,700,000
Current Risk Management Liabilities	[8]	193,000,000.0		424,500,000
Long-term Risk Management Liabilities	[8]	222,200,000		244,500,000
Total Liabilities	[8]	415,200,000		669,000,000.0
Total MTM Derivative Contract Net Assets (Liabilities)	[8]	99,800,000		135,700,000
Commodity [Member] | Risk Management Contracts [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[8]	400,000		0
Long-term Risk Management Assets	[8]	0		0
Total Assets	[8]	400,000		0
Current Risk Management Liabilities	[8]	0		0
Long-term Risk Management Liabilities	[8]	0		0
Total Liabilities	[8]	0		0
Total MTM Derivative Contract Net Assets (Liabilities)	[8]	400,000		0
Commodity [Member] | Risk Management Contracts [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[8]	38,800,000		124,400,000
Long-term Risk Management Assets	[8]	700,000		900,000
Total Assets	[8]	39,500,000		125,300,000
Current Risk Management Liabilities	[8]	19,700,000		86,200,000
Long-term Risk Management Liabilities	[8]	600,000		700,000
Total Liabilities	[8]	20,300,000		86,900,000
Total MTM Derivative Contract Net Assets (Liabilities)	[8]	19,200,000		38,400,000
Commodity [Member] | Risk Management Contracts [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[8]	17,200,000		66,900,000
Long-term Risk Management Assets	[8]	500,000		500,000
Total Assets	[8]	17,700,000		67,400,000
Current Risk Management Liabilities	[8]	12,100,000		55,200,000
Long-term Risk Management Liabilities	[8]	400,000		400,000
Total Liabilities	[8]	12,500,000		55,600,000
Total MTM Derivative Contract Net Assets (Liabilities)	[8]	5,200,000		11,800,000
Commodity [Member] | Risk Management Contracts [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[8]	300,000		0
Long-term Risk Management Assets	[8]	0		0
Total Assets	[8]	300,000		0
Current Risk Management Liabilities	[8]	8,700,000		7,300,000
Long-term Risk Management Liabilities	[8]	101,600,000		96,300,000
Total Liabilities	[8]	110,300,000		103,600,000
Total MTM Derivative Contract Net Assets (Liabilities)	[8]	(110,000,000.0)		(103,600,000)
Commodity [Member] | Risk Management Contracts [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[8]	10,500,000		16,300,000
Long-term Risk Management Assets	[8]	0		0
Total Assets	[8]	10,500,000		16,300,000
Current Risk Management Liabilities	[8]	0		500,000
Long-term Risk Management Liabilities	[8]	0		0
Total Liabilities	[8]	0		500,000
Total MTM Derivative Contract Net Assets (Liabilities)	[8]	10,500,000		15,800,000
Commodity [Member] | Risk Management Contracts [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[8]	3,400,000		6,500,000
Long-term Risk Management Assets	[8]	0		0
Total Assets	[8]	3,400,000		6,500,000
Current Risk Management Liabilities	[8]	700,000		2,000,000.0
Long-term Risk Management Liabilities	[8]	1,000,000.0		3,100,000
Total Liabilities	[8]	1,700,000		5,100,000
Total MTM Derivative Contract Net Assets (Liabilities)	[8]	1,700,000		1,400,000
Commodity [Member] | Hedging Contracts [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[8]	21,100,000		11,500,000
Long-term Risk Management Assets	[8]	18,000,000.0		11,000,000.0
Total Assets	[8]	39,100,000		22,500,000
Current Risk Management Liabilities	[8]	54,400,000		72,300,000
Long-term Risk Management Liabilities	[8]	60,100,000		75,700,000
Total Liabilities	[8]	114,500,000		148,000,000.0
Total MTM Derivative Contract Net Assets (Liabilities)	[8]	(75,400,000)		(125,500,000)
Interest Rate [Member]
Commodity
Derivative, Notional Amount		1,150,000,000.0		625,000,000.0
Impact of Cash Flow Hedges on the Balance Sheet
AOCI Gain (Loss) Net of Tax		(47,500,000)		(11,500,000)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		$ (5,700,000)		(2,100,000)
Derivatives and Hedging (Textuals)
Maximum Length of Time Hedged in Price Risk Cash Flow Hedge		120 months
Interest Rate [Member] | AEP Texas Inc. [Member]
Commodity
Derivative, Notional Amount		$ 0		0
Impact of Cash Flow Hedges on the Balance Sheet
AOCI Gain (Loss) Net of Tax		(2,300,000)		(3,400,000)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		(1,100,000)		(1,100,000)
Interest Rate [Member] | Appalachian Power Co [Member]
Commodity
Derivative, Notional Amount		200,000,000.0		0
Impact of Cash Flow Hedges on the Balance Sheet
AOCI Gain (Loss) Net of Tax		(800,000)		900,000
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		400,000		900,000
Interest Rate [Member] | Indiana Michigan Power Co [Member]
Commodity
Derivative, Notional Amount		0		0
Impact of Cash Flow Hedges on the Balance Sheet
AOCI Gain (Loss) Net of Tax		(8,300,000)		(9,900,000)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		(1,600,000)		(1,600,000)
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 Balance Sheet
AOCI Gain (Loss) Net of Tax		100,000		1,100,000
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		100,000		1,000,000.0
Interest Rate [Member] | Southwestern Electric Power Co [Member]
Commodity
Derivative, Notional Amount		0		0
Impact of Cash Flow Hedges on the Balance Sheet
AOCI Gain (Loss) Net of Tax		(300,000)		(1,800,000)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months		(1,500,000)		(1,500,000)
Interest Rate [Member] | Hedging Contracts [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[8]	5,000,000.0		6,500,000
Long-term Risk Management Assets	[8]	0		12,600,000
Total Assets	[8]	5,000,000.0		19,100,000
Current Risk Management Liabilities	[8]	3,400,000		0
Long-term Risk Management Liabilities	[8]	4,100,000		0
Total Liabilities	[8]	7,500,000		0
Total MTM Derivative Contract Net Assets (Liabilities)	[8]	(2,500,000)		19,100,000
Interest Rate [Member] | Hedging Contracts [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[8]	2,400,000
Long-term Risk Management Assets	[8]	0
Total Assets	[8]	2,400,000
Current Risk Management Liabilities	[8]	3,400,000
Long-term Risk Management Liabilities	[8]	0
Total Liabilities	[8]	3,400,000
Total MTM Derivative Contract Net Assets (Liabilities)	[8]	(1,000,000.0)
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		265,200,000		531,900,000
Long-term Risk Management Assets		293,900,000		314,400,000
Total Assets		559,100,000		846,300,000
Current Risk Management Liabilities		250,800,000		496,800,000
Long-term Risk Management Liabilities		286,400,000		320,200,000
Total Liabilities		537,200,000		817,000,000.0
Total MTM Derivative Contract Net Assets (Liabilities)		21,900,000		29,300,000
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		41,200,000
Long-term Risk Management Assets		700,000
Total Assets		41,900,000
Current Risk Management Liabilities		23,100,000
Long-term Risk Management Liabilities		600,000
Total Liabilities		23,700,000
Total MTM Derivative Contract Net Assets (Liabilities)		18,200,000
Gross Amounts Offset in the Statement of Financial Position [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[9]	(170,500,000)		(359,100,000)
Long-term Risk Management Assets	[9]	(51,700,000)		(47,800,000)
Total Assets	[9]	(222,200,000)		(406,900,000)
Current Risk Management Liabilities	[9]	(172,000,000.0)		(382,500,000)
Long-term Risk Management Liabilities	[9]	(53,600,000)		(58,400,000)
Total Liabilities	[9]	(225,600,000)		(440,900,000)
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	3,400,000		34,000,000.0
Gross Amounts Offset in the Statement of Financial Position [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[9]	(400,000)		0
Long-term Risk Management Assets	[9]	0		0
Total Assets	[9]	(400,000)		0
Current Risk Management Liabilities	[9]	0		0
Long-term Risk Management Liabilities	[9]	0		0
Total Liabilities	[9]	0		0
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	(400,000)		0
Gross Amounts Offset in the Statement of Financial Position [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[9]	(18,800,000)		(85,000,000.0)
Long-term Risk Management Assets	[9]	(600,000)		(800,000)
Total Assets	[9]	(19,400,000)		(85,800,000)
Current Risk Management Liabilities	[9]	(18,500,000)		(84,300,000)
Long-term Risk Management Liabilities	[9]	(500,000)		(700,000)
Total Liabilities	[9]	(19,000,000.0)		(85,000,000.0)
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	(400,000)		(800,000)
Gross Amounts Offset in the Statement of Financial Position [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[9]	(13,600,000)		(57,100,000)
Long-term Risk Management Assets	[9]	(400,000)		(400,000)
Total Assets	[9]	(14,000,000.0)		(57,500,000)
Current Risk Management Liabilities	[9]	(12,000,000.0)		(54,700,000)
Long-term Risk Management Liabilities	[9]	(300,000)		(400,000)
Total Liabilities	[9]	(12,300,000)		(55,100,000)
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	(1,700,000)		(2,400,000)
Gross Amounts Offset in the Statement of Financial Position [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[9]	(300,000)		0
Long-term Risk Management Assets	[9]	0		0
Total Assets	[9]	(300,000)		0
Current Risk Management Liabilities	[9]	0		0
Long-term Risk Management Liabilities	[9]	0		0
Total Liabilities	[9]	0		0
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	(300,000)		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	[9]	(200,000)		(500,000)
Long-term Risk Management Assets	[9]	0		0
Total Assets	[9]	(200,000)		(500,000)
Current Risk Management Liabilities	[9]	0		(500,000)
Long-term Risk Management Liabilities	[9]	0		0
Total Liabilities	[9]	0		(500,000)
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	(200,000)		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	[9]	(200,000)		(100,000)
Long-term Risk Management Assets	[9]	0		0
Total Assets	[9]	(200,000)		(100,000)
Current Risk Management Liabilities	[9]	0		(100,000)
Long-term Risk Management Liabilities	[9]	0		0
Total Liabilities	[9]	0		(100,000)
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	(200,000)		0
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[10]	94,700,000		172,800,000
Long-term Risk Management Assets	[10]	242,200,000		266,600,000
Total Assets	[10]	336,900,000		439,400,000
Current Risk Management Liabilities	[10]	78,800,000		114,300,000
Long-term Risk Management Liabilities	[10]	232,800,000		261,800,000
Total Liabilities	[10]	311,600,000		376,100,000
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	25,300,000		63,300,000
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	[10]	0		0
Long-term Risk Management Assets	[10]	0		0
Total Assets	[10]	0		0
Current Risk Management Liabilities	[10]	0		0
Long-term Risk Management Liabilities	[10]	0		0
Total Liabilities	[10]	0		0
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	0		0
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	[10]	22,400,000		39,400,000
Long-term Risk Management Assets	[10]	100,000		100,000
Total Assets	[10]	22,500,000		39,500,000
Current Risk Management Liabilities	[10]	4,600,000		1,900,000
Long-term Risk Management Liabilities	[10]	100,000		0
Total Liabilities	[10]	4,700,000		1,900,000
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	17,800,000		37,600,000
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	[10]	3,600,000		9,800,000
Long-term Risk Management Assets	[10]	100,000		100,000
Total Assets	[10]	3,700,000		9,900,000
Current Risk Management Liabilities	[10]	100,000		500,000
Long-term Risk Management Liabilities	[10]	100,000		0
Total Liabilities	[10]	200,000		500,000
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	3,500,000		9,400,000
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	[10]	0		0
Long-term Risk Management Assets	[10]	0		0
Total Assets	[10]	0		0
Current Risk Management Liabilities	[10]	8,700,000		7,300,000
Long-term Risk Management Liabilities	[10]	101,600,000		96,300,000
Total Liabilities	[10]	110,300,000		103,600,000
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	(110,300,000)		(103,600,000)
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	[10]	10,300,000		15,800,000
Long-term Risk Management Assets	[10]	0		0
Total Assets	[10]	10,300,000		15,800,000
Current Risk Management Liabilities	[10]	0		0
Long-term Risk Management Liabilities	[10]	0		0
Total Liabilities	[10]	0		0
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	10,300,000		15,800,000
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	[10]	3,200,000		6,400,000
Long-term Risk Management Assets	[10]	0		0
Total Assets	[10]	3,200,000		6,400,000
Current Risk Management Liabilities	[10]	700,000		1,900,000
Long-term Risk Management Liabilities	[10]	1,000,000.0		3,100,000
Total Liabilities	[10]	1,700,000		5,000,000.0
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	$ 1,500,000		$ 1,400,000
Power [Member]
Commodity
Derivative, Energy Notional Amount | MWh		331.3		365.9
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		46.9		61.0
Power [Member] | Indiana Michigan Power Co [Member]
Commodity
Derivative, Energy Notional Amount | MWh		19.7		26.8
Power [Member] | Ohio Power Co [Member]
Commodity
Derivative, Energy Notional Amount | MWh		3.0		7.1
Power [Member] | Public Service Co Of Oklahoma [Member]
Commodity
Derivative, Energy Notional Amount | MWh		11.9		14.9
Power [Member] | Southwestern Electric Power Co [Member]
Commodity
Derivative, Energy Notional Amount | MWh		4.0		4.4
Natural Gas [Member]
Commodity
Derivative, Energy Notional Amount | MMBTU		26.9		40.7
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		0.0		0.0
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		0.0		0.0
Natural Gas [Member] | Southwestern Electric Power Co [Member]
Commodity
Derivative, Energy Notional Amount | MMBTU		7.9		11.6
Heating Oil and Gasoline [Member]
Commodity
Derivative, Volume Notional Amount | gal		6.9		6.9
Heating Oil and Gasoline [Member] | AEP Texas Inc. [Member]
Commodity
Derivative, Volume Notional Amount | gal		1.8		1.8
Heating Oil and Gasoline [Member] | Appalachian Power Co [Member]
Commodity
Derivative, Volume Notional Amount | gal		1.1		1.1
Heating Oil and Gasoline [Member] | Indiana Michigan Power Co [Member]
Commodity
Derivative, Volume Notional Amount | gal		0.6		0.6
Heating Oil and Gasoline [Member] | Ohio Power Co [Member]
Commodity
Derivative, Volume Notional Amount | gal		1.4		1.4
Heating Oil and Gasoline [Member] | Public Service Co Of Oklahoma [Member]
Commodity
Derivative, Volume Notional Amount | gal		0.7		0.7
Heating Oil and Gasoline [Member] | Southwestern Electric Power Co [Member]
Commodity
Derivative, Volume Notional Amount | gal		0.9		0.9
Interest Rate Contract [Member]
Commodity
Derivative, Notional Amount		$ 129,800,000		$ 140,100,000
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
Warrants Held in Investee [Member]
Fair Value of Derivative Instruments
Total Assets		32,000,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		32,000,000
Derivatives and Hedging (Textuals)
Cost of Investment in Privately Held Investee		8,000,000
Vertically Integrated Utilities Revenues [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		800,000		700,000		(10,400,000)
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		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		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		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		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		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		0
Generation and Marketing Revenues [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		9,500,000		25,100,000		38,900,000
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		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		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		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		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		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		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		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		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		400,000		100,000		(1,900,000)
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		100,000		500,000		(8,200,000)
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		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		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		100,000		100,000		100,000
Purchased Electricity for Resale [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		1,400,000		1,900,000		8,600,000
Purchased Electricity for Resale [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		0
Purchased Electricity for Resale [Member] | Appalachian Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		1,200,000		1,600,000		7,600,000
Purchased Electricity for Resale [Member] | Indiana Michigan Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		100,000		100,000		800,000
Purchased Electricity for Resale [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		0
Purchased Electricity for Resale [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		0
Purchased Electricity for Resale [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		0
Other Operation Expense [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(2,000,000.0)		(800,000)		1,700,000
Other Operation Expense [Member] | AEP Texas Inc. [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(600,000)		(200,000)		400,000
Other Operation Expense [Member] | Appalachian Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(200,000)		(100,000)		200,000
Other Operation 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		(200,000)		(100,000)		200,000
Other Operation Expense [Member] | Ohio Power Co [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(300,000)		(200,000)		300,000
Other Operation 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		(200,000)		(100,000)		200,000
Other Operation 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		(300,000)		(100,000)		200,000
Maintenance Expense [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(2,900,000)		(800,000)		1,900,000
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		(800,000)		(200,000)		400,000
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		(400,000)		(200,000)		400,000
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		(300,000)		(100,000)		200,000
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		(500,000)		(200,000)		400,000
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		(300,000)		(100,000)		200,000
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		(400,000)		(100,000)		200,000
Regulatory Assets [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[11]	(4,800,000)		(3,700,000)		27,900,000
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	[11]	0		700,000		(700,000)
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	[11]	0		300,000		(700,000)
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	[11]	(100,000)		300,000		7,100,000
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	[11]	(6,600,000)		(3,700,000)		24,900,000
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	[11]	0		1,200,000		(1,100,000)
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	[11]	1,400,000		(1,500,000)		(1,200,000)
Regulatory Liabilities [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[11]	114,900,000		102,600,000		222,700,000
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	[11]	400,000		0		(500,000)
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	[11]	20,300,000		2,400,000		135,500,000
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	[11]	12,400,000		24,500,000		11,600,000
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	[11]	12,400,000		10,100,000		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	[11]	39,100,000		34,600,000		37,300,000
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	[11]	20,200,000		26,600,000		11,900,000
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Commodity [Member]
Change in Fair Value Recognized in AOCI		(89,200,000)		(127,200,000)		37,300,000
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Commodity [Member] | Appalachian Power Co [Member]
Change in Fair Value Recognized in AOCI						(700,000)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate [Member]
Change in Fair Value Recognized in AOCI		(39,900,000)	[12]	(200,000)	[12]	2,300,000
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate [Member] | AEP Texas Inc. [Member]
Change in Fair Value Recognized in AOCI		100,000		0		0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate [Member] | Appalachian Power Co [Member]
Change in Fair Value Recognized in AOCI		(700,000)		0		0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate [Member] | Indiana Michigan Power Co [Member]
Change in Fair Value Recognized in AOCI		0		0		0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate [Member] | Ohio Power Co [Member]
Change in Fair Value Recognized in AOCI		0		0		0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate [Member] | Public Service Co Of Oklahoma [Member]
Change in Fair Value Recognized in AOCI		0		0		0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate [Member] | Southwestern Electric Power Co [Member]
Change in Fair Value Recognized in AOCI		0		0		$ 2,300,000
Fair Value, Inputs, Level 3 [Member]
Fair Value of Derivative Instruments
Total Assets		256,300,000		372,400,000
Total Liabilities		174,800,000		262,500,000
Fair Value, Inputs, Level 3 [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Total Assets		19,900,000		40,500,000
Total Liabilities		600,000		2,800,000
Fair Value, Inputs, Level 3 [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Total Assets		2,500,000		8,000,000.0
Total Liabilities		400,000		2,200,000
Fair Value, Inputs, Level 3 [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Total Assets		3,300,000		6,500,000
Total Liabilities		1,700,000		5,100,000
Fair Value, Inputs, Level 3 [Member] | Risk Management Contracts [Member]
Fair Value of Derivative Instruments
Total Assets	[4]	252,400,000	[5]	369,200,000	[6]
Total Liabilities	[4]	167,200,000	[5]	224,000,000.0	[6]
Fair Value, Inputs, Level 3 [Member] | Risk Management Contracts [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Total Assets	[4]	0
Fair Value, Inputs, Level 3 [Member] | Risk Management Contracts [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	19,900,000		40,500,000
Total Liabilities	[4],[7]	600,000		2,800,000
Fair Value, Inputs, Level 3 [Member] | Risk Management Contracts [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	2,500,000		8,000,000.0
Total Liabilities	[4],[7]	400,000		2,200,000
Fair Value, Inputs, Level 3 [Member] | Risk Management Contracts [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	0
Total Liabilities	[4],[7]	110,300,000		103,600,000
Fair Value, Inputs, Level 3 [Member] | Risk Management Contracts [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	10,300,000		16,300,000
Total Liabilities	[4],[7]			500,000
Fair Value, Inputs, Level 3 [Member] | Risk Management Contracts [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	3,300,000		6,500,000
Total Liabilities	[4],[7]	1,700,000		5,100,000
Fair Value, Inputs, Level 3 [Member] | Maturity Period 5 [Member]
Maturity Of Net Fair Value Of Risk Management Contracts Prior To Cash Collateral Assets Or Liabilities				25,000,000
Fair Value, Inputs, Level 3 [Member] | Maturity Period Eight [Member]
Maturity Of Net Fair Value Of Risk Management Contracts Prior To Cash Collateral Assets Or Liabilities		(13,000,000)
Fair Value, Inputs, Level 3 [Member] | 2025-2026 [Member]
Maturity Of Net Fair Value Of Risk Management Contracts Prior To Cash Collateral Assets Or Liabilities		14,000,000
Fair Value, Inputs, Level 3 [Member] | Maturity Period Seven [Member]
Maturity Of Net Fair Value Of Risk Management Contracts Prior To Cash Collateral Assets Or Liabilities				(12,000,000)
Fair Value, Inputs, Level 2 [Member]
Fair Value of Derivative Instruments
Total Assets		298,200,000		474,200,000
Total Liabilities		357,800,000		555,300,000
Fair Value, Inputs, Level 2 [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Total Assets		21,800,000
Total Liabilities		22,900,000
Fair Value, Inputs, Level 2 [Member] | Risk Management Contracts [Member]
Fair Value of Derivative Instruments
Total Assets	[4]	258,800,000	[5]	440,100,000	[6]
Total Liabilities	[4]	244,200,000	[5]	450,000,000.0	[6]
Fair Value, Inputs, Level 2 [Member] | Risk Management Contracts [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Total Assets	[4]	400,000
Fair Value, Inputs, Level 2 [Member] | Risk Management Contracts [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	19,400,000		84,600,000
Total Liabilities	[4],[7]	19,500,000		84,000,000.0
Fair Value, Inputs, Level 2 [Member] | Risk Management Contracts [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	15,100,000		59,500,000
Total Liabilities	[4],[7]	12,000,000.0		53,400,000
Fair Value, Inputs, Level 2 [Member] | Risk Management Contracts [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	300,000
Total Liabilities	[4],[7]	0		0
Fair Value, Inputs, Level 2 [Member] | Risk Management Contracts [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	200,000		0
Total Liabilities	[4],[7]			0
Fair Value, Inputs, Level 2 [Member] | Risk Management Contracts [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[4],[7]	100,000		0
Total Liabilities	[4],[7]	0		$ 0
Fair Value, Inputs, Level 2 [Member] | Maturity Period Eight [Member]
Maturity Of Net Fair Value Of Risk Management Contracts Prior To Cash Collateral Assets Or Liabilities		1,000,000
Fair Value, Inputs, Level 2 [Member] | 2025-2026 [Member]
Maturity Of Net Fair Value Of Risk Management Contracts Prior To Cash Collateral Assets Or Liabilities		$ 11,000,000

[1] Amounts include $(53) million and $0 as of December 31, 2020 and 2019, respectively, for the fair value hedge adjustment of hedged debt obligations for which hedge accounting has been discontinued

[2] Amounts included on the balance sheets within Long-term Debt Due within One Year and Long-term Debt, respectively.

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

[4] 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.”

[5] The December 31, 2020 maturities of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), were as follows: Level 2 matures $3 million in periods 2022-2024, $11 million in periods 2025-2026 and $1 million in periods 2027-2033; Level 3 matures $47 million in 2021, $37 million in periods 2022-2024, $14 million in periods 2025-2026 and $(13) million in periods 2027-2033. Risk management commodity contracts are substantially comprised of power contracts.

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

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

[8] Derivative instruments within these categories are reported gross.  These instruments are subject to master netting agreements and are presented on the balance sheets on a net basis in accordance with the accounting guidance for “Derivatives and Hedging.”

[9] Amounts include counterparty netting of risk management and hedging contracts and associated cash collateral in accordance with the accounting guidance for “Derivatives and Hedging.”

[10] All derivative contracts subject to a master netting arrangement or similar agreement are offset in the statement of financial position.

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

[12] The change in fair value includes $6 million and $4 million related to AEP's investment in joint venture wind farms acquired as part of the purchase of Sempra Renewables LLC for the years ended December 31, 2020 and December 31, 2019. See “Sempra Renewables LLC” section of Note 17 for additional information.