Derivatives and Hedging (Details) gal in Millions, MWh in Millions, MMBTU in Millions		3 Months Ended			9 Months Ended			12 Months Ended
		Sep. 30, 2019 USD ($) MWh MMBTU gal		Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) MWh MMBTU gal		Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($) MWh MMBTU gal
Interest Expense		$ 275,100,000		$ 256,800,000	$ 781,600,000		$ 733,100,000
Cash Collateral Netting
Cash Collateral Received Netted Against Risk Management Assets		0			0			$ 18,000,000
Cash Collateral Paid Netted Against Risk Management Liabilities		21,000,000			21,000,000			4,000,000
Fair Value of Derivative Instruments
Current Risk Management Assets		186,700,000			186,700,000			162,800,000
Long-term Risk Management Assets		299,000,000.0			299,000,000.0			254,000,000.0
Total Assets		485,700,000			485,700,000			416,800,000
Current Risk Management Liabilities		75,300,000			75,300,000			55,000,000.0
Long-term Risk Management Liabilities		298,600,000			298,600,000			263,400,000
Total Liabilities		373,900,000			373,900,000			318,400,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		43,100,000		39,800,000	73,700,000		268,800,000
Carrying Amount of Hedged Asset (Liability)	[1]	(521,200,000)			(521,200,000)			(478,300,000)
Cumulative Fair Value Hedging Adjustment in the Carrying Amount of the Hedged Asset (Liability)	[1]	(25,100,000)			(25,100,000)			17,400,000
Gain (Loss) on Hedging Instruments
Gain (Loss) on Fair Value Hedging Instruments	[2]	13,200,000		(6,300,000)	42,500,000		(28,100,000)
Gain (Loss) on Fair Value Portion of Long Term Debt	[2]	(13,200,000)		6,300,000	(42,500,000)		28,100,000
Collateral Triggering Events [Abstract]
Fair Value Of Derivative Liabilities Subject To Cross Default Provisions		261,000,000.0			261,000,000.0			225,500,000
Amount of Cash Collateral Posted		3,400,000			3,400,000			1,800,000
Additional Settlement Liability if Cross Default Provision is Triggered		230,700,000			230,700,000			181,000,000.0
AEP Texas Inc. [Member]
Interest Expense		35,800,000		37,300,000	92,700,000		108,900,000
Fair Value of Derivative Instruments
Current Risk Management Liabilities		300,000			300,000			200,000
Long-term Risk Management Liabilities		100,000			100,000			0
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(200,000)		200,000	100,000		600,000
AEP Transmission Co [Member]
Interest Expense		26,400,000		19,800,000	69,500,000		60,700,000
Appalachian Power Co [Member]
Interest Expense		51,600,000		50,800,000	152,500,000		146,000,000.0
Fair Value of Derivative Instruments
Current Risk Management Assets		56,500,000			56,500,000			57,200,000
Long-term Risk Management Assets		200,000			200,000			900,000
Current Risk Management Liabilities		1,100,000			1,100,000			400,000
Long-term Risk Management Liabilities		300,000			300,000			200,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		10,600,000		24,000,000.0	(3,500,000)		133,800,000
Collateral Triggering Events [Abstract]
Fair Value Of Derivative Liabilities Subject To Cross Default Provisions		3,900,000			3,900,000			900,000
Amount of Cash Collateral Posted		0			0			0
Additional Settlement Liability if Cross Default Provision is Triggered		200,000			200,000			0
Indiana Michigan Power Co [Member]
Interest Expense		28,800,000		34,500,000	85,900,000		95,600,000
Fair Value of Derivative Instruments
Current Risk Management Assets		10,500,000			10,500,000			8,600,000
Long-term Risk Management Assets		100,000			100,000			600,000
Current Risk Management Liabilities		200,000			200,000			300,000
Long-term Risk Management Liabilities		0			0			100,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		3,200,000		(3,400,000)	17,800,000		4,800,000
Collateral Triggering Events [Abstract]
Fair Value Of Derivative Liabilities Subject To Cross Default Provisions		2,300,000			2,300,000			500,000
Amount of Cash Collateral Posted		0			0			0
Additional Settlement Liability if Cross Default Provision is Triggered		100,000			100,000			0
Ohio Power Co [Member]
Interest Expense		27,900,000		26,100,000	78,100,000		76,600,000
Fair Value of Derivative Instruments
Current Risk Management Liabilities		7,200,000			7,200,000			5,800,000
Long-term Risk Management Liabilities		105,700,000			105,700,000			93,800,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(2,700,000)		(9,100,000)	(20,100,000)		33,000,000.0
Public Service Co Of Oklahoma [Member]
Interest Expense		16,100,000		16,400,000	50,300,000		47,400,000
Fair Value of Derivative Instruments
Current Risk Management Assets		21,700,000			21,700,000			10,400,000
Current Risk Management Liabilities		300,000			300,000			1,000,000.0
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		4,100,000		3,500,000	27,400,000		34,600,000
Southwestern Electric Power Co [Member]
Interest Expense		29,200,000		32,700,000	89,400,000		95,800,000
Fair Value of Derivative Instruments
Current Risk Management Assets		9,400,000			9,400,000			4,800,000
Current Risk Management Liabilities		1,700,000			1,700,000			400,000
Long-term Risk Management Liabilities		3,000,000.0			3,000,000.0			2,200,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		2,900,000		1,100,000	22,400,000		6,400,000
Collateral Triggering Events [Abstract]
Fair Value Of Derivative Liabilities Subject To Cross Default Provisions		4,700,000			4,700,000			2,300,000
Amount of Cash Collateral Posted		0			0			0
Additional Settlement Liability if Cross Default Provision is Triggered		2,800,000			2,800,000			2,300,000
Risk Management Contracts [Member]
Fair Value of Derivative Instruments
Total Assets	[3]	446,200,000	[4]		446,200,000	[4]		382,700,000	[5]
Total Liabilities	[3]	264,100,000	[4]		264,100,000	[4]		242,100,000	[5]
Risk Management Contracts [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Total Liabilities	[3]	400,000			400,000			200,000
Risk Management Contracts [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[3],[6]	56,700,000			56,700,000			58,100,000
Total Liabilities	[3],[6]	1,400,000			1,400,000			600,000
Risk Management Contracts [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[3],[6]	10,600,000			10,600,000			9,200,000
Total Liabilities	[3],[6]	200,000			200,000			400,000
Risk Management Contracts [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Total Liabilities	[3],[6]	112,900,000			112,900,000			99,600,000
Risk Management Contracts [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Total Assets	[3],[6]	21,700,000			21,700,000			10,400,000
Total Liabilities	[3],[6]	300,000			300,000			1,000,000.0
Risk Management Contracts [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Total Assets	[3],[6]	9,400,000			9,400,000			4,800,000
Total Liabilities	[3],[6]	4,700,000			4,700,000			2,600,000
Commodity [Member]
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		(82,200,000)			(82,200,000)			(23,000,000.0)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months					$ (24,200,000)			10,400,000
Derivatives and Hedging (Textuals) [Abstract]
Maximum Term for Exposure to Variability of Future Cash Flows					123 months
Cross Default Provisions Maximum Third Party Obligation Amount		50,000,000			$ 50,000,000			50,000,000
Commodity [Member] | Risk Management Contracts [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[7]	337,000,000.0			337,000,000.0			397,500,000
Long-term Risk Management Assets	[7]	319,000,000.0			319,000,000.0			276,400,000
Total Assets	[7]	656,000,000.0			656,000,000.0			673,900,000
Current Risk Management Liabilities	[7]	213,400,000			213,400,000			293,800,000
Long-term Risk Management Liabilities	[7]	281,700,000			281,700,000			225,700,000
Total Liabilities	[7]	495,100,000			495,100,000			519,500,000
Total MTM Derivative Contract Net Assets (Liabilities)	[7]	160,900,000			160,900,000			154,400,000
Commodity [Member] | Risk Management Contracts [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[7]	0			0			0
Long-term Risk Management Assets	[7]	0			0			0
Total Assets	[7]	0			0			0
Current Risk Management Liabilities	[7]	400,000			400,000			700,000
Long-term Risk Management Liabilities	[7]	0			0			0
Total Liabilities	[7]	400,000			400,000			700,000
Total MTM Derivative Contract Net Assets (Liabilities)	[7]	(400,000)			(400,000)			(700,000)
Commodity [Member] | Risk Management Contracts [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[7]	86,300,000			86,300,000			114,400,000
Long-term Risk Management Assets	[7]	4,100,000			4,100,000			3,100,000
Total Assets	[7]	90,400,000			90,400,000			117,500,000
Current Risk Management Liabilities	[7]	32,300,000			32,300,000			56,700,000
Long-term Risk Management Liabilities	[7]	4,400,000			4,400,000			2,400,000
Total Liabilities	[7]	36,700,000			36,700,000			59,100,000
Total MTM Derivative Contract Net Assets (Liabilities)	[7]	53,700,000			53,700,000			58,400,000
Commodity [Member] | Risk Management Contracts [Member] | Indiana Michigan Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[7]	30,500,000			30,500,000			50,400,000
Long-term Risk Management Assets	[7]	2,700,000			2,700,000			2,000,000.0
Total Assets	[7]	33,200,000			33,200,000			52,400,000
Current Risk Management Liabilities	[7]	21,000,000.0			21,000,000.0			41,100,000
Long-term Risk Management Liabilities	[7]	2,700,000			2,700,000			1,600,000
Total Liabilities	[7]	23,700,000			23,700,000			42,700,000
Total MTM Derivative Contract Net Assets (Liabilities)	[7]	9,500,000			9,500,000			9,700,000
Commodity [Member] | Risk Management Contracts [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[7]	0			0			0
Long-term Risk Management Assets	[7]	0			0			0
Total Assets	[7]	0			0			0
Current Risk Management Liabilities	[7]	7,200,000			7,200,000			6,400,000
Long-term Risk Management Liabilities	[7]	105,700,000			105,700,000			93,800,000
Total Liabilities	[7]	112,900,000			112,900,000			100,200,000
Total MTM Derivative Contract Net Assets (Liabilities)	[7]	(112,900,000)			(112,900,000)			(100,200,000)
Commodity [Member] | Risk Management Contracts [Member] | Public Service Co Of Oklahoma [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[7]	21,900,000			21,900,000			10,900,000
Long-term Risk Management Assets	[7]	0			0			0
Total Assets	[7]	21,900,000			21,900,000			10,900,000
Current Risk Management Liabilities	[7]	500,000			500,000			1,700,000
Long-term Risk Management Liabilities	[7]	0			0			0
Total Liabilities	[7]	500,000			500,000			1,700,000
Total MTM Derivative Contract Net Assets (Liabilities)	[7]	21,400,000			21,400,000			9,200,000
Commodity [Member] | Risk Management Contracts [Member] | Southwestern Electric Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[7]	9,800,000			9,800,000			5,600,000
Long-term Risk Management Assets	[7]	0			0			0
Total Assets	[7]	9,800,000			9,800,000			5,600,000
Current Risk Management Liabilities	[7]	2,100,000			2,100,000			1,500,000
Long-term Risk Management Liabilities	[7]	3,000,000.0			3,000,000.0			2,200,000
Total Liabilities	[7]	5,100,000			5,100,000			3,700,000
Total MTM Derivative Contract Net Assets (Liabilities)	[7]	4,700,000			4,700,000			1,900,000
Commodity [Member] | Hedging Contracts [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[7]	16,500,000			16,500,000			28,500,000
Long-term Risk Management Assets	[7]	10,000,000.0			10,000,000.0			16,000,000.0
Total Assets	[7]	26,500,000			26,500,000			44,500,000
Current Risk Management Liabilities	[7]	36,400,000			36,400,000			13,200,000
Long-term Risk Management Liabilities	[7]	87,400,000			87,400,000			56,100,000
Total Liabilities	[7]	123,800,000			123,800,000			69,300,000
Total MTM Derivative Contract Net Assets (Liabilities)	[7]	(97,300,000)			(97,300,000)			(24,800,000)
Interest Rate [Member]
Commodity:
Derivative, Notional Amount		600,000,000.0			600,000,000.0			500,000,000.0
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		(16,700,000)	[8]		(16,700,000)	[8]		(12,600,000)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months					$ (3,700,000)			(1,100,000)
Derivatives and Hedging (Textuals) [Abstract]
Maximum Term for Exposure to Variability of Future Cash Flows					135 months
Interest Rate [Member] | AEP Texas Inc. [Member]
Commodity:
Derivative, Notional Amount		0			$ 0			0
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		(3,600,000)			(3,600,000)			(4,400,000)
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		0			0			0
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		1,100,000			1,100,000			1,800,000
Portion Expected to be Reclassified to Net Income During the Next Twelve Months					900,000			900,000
Interest Rate [Member] | Indiana Michigan Power Co [Member]
Commodity:
Derivative, Notional Amount		0			0			0
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		(10,300,000)			(10,300,000)			(11,500,000)
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			0
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		0			0			1,000,000.0
Portion Expected to be Reclassified to Net Income During the Next Twelve Months					0			1,000,000.0
Interest Rate [Member] | Public Service Co Of Oklahoma [Member]
Commodity:
Derivative, Notional Amount		0			0			0
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		1,400,000			1,400,000			2,100,000
Portion Expected to be Reclassified to Net Income During the Next Twelve Months					1,000,000.0			1,000,000.0
Interest Rate [Member] | Southwestern Electric Power Co [Member]
Commodity:
Derivative, Notional Amount		0			0			0
Impact of Cash Flow Hedges on the Condensed Balance Sheet
AOCI Gain (Loss) Net of Tax		(2,200,000)			(2,200,000)			(3,300,000)
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	[7]	1,900,000			1,900,000			0
Long-term Risk Management Assets	[7]	25,300,000			25,300,000			0
Total Assets	[7]	27,200,000			27,200,000			0
Current Risk Management Liabilities	[7]	200,000			200,000			2,000,000.0
Long-term Risk Management Liabilities	[7]	0			0			15,400,000
Total Liabilities	[7]	200,000			200,000			17,400,000
Total MTM Derivative Contract Net Assets (Liabilities)	[7]	27,000,000.0			27,000,000.0			(17,400,000)
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets		355,400,000			355,400,000			426,000,000.0
Long-term Risk Management Assets		354,300,000			354,300,000			292,400,000
Total Assets		709,700,000			709,700,000			718,400,000
Current Risk Management Liabilities		250,000,000.0			250,000,000.0			309,000,000.0
Long-term Risk Management Liabilities		369,100,000			369,100,000			297,200,000
Total Liabilities		619,100,000			619,100,000			606,200,000
Total MTM Derivative Contract Net Assets (Liabilities)		90,600,000			90,600,000			112,200,000
Gross Amounts Offset in the Statement of Financial Position [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[9]	(168,700,000)			(168,700,000)			(263,200,000)
Long-term Risk Management Assets	[9]	(55,300,000)			(55,300,000)			(38,400,000)
Total Assets	[9]	(224,000,000.0)			(224,000,000.0)			(301,600,000)
Current Risk Management Liabilities	[9]	(174,700,000)			(174,700,000)			(254,000,000.0)
Long-term Risk Management Liabilities	[9]	(70,500,000)			(70,500,000)			(33,800,000)
Total Liabilities	[9]	(245,200,000)			(245,200,000)			(287,800,000)
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	21,200,000			21,200,000			(13,800,000)
Gross Amounts Offset in the Statement of Financial Position [Member] | AEP Texas Inc. [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[9]	0			0			0
Long-term Risk Management Assets	[9]	0			0			0
Total Assets	[9]	0			0			0
Current Risk Management Liabilities	[9]	(100,000)			(100,000)			(500,000)
Long-term Risk Management Liabilities	[9]	100,000			100,000			0
Total Liabilities	[9]	0			0			(500,000)
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	0			0			500,000
Gross Amounts Offset in the Statement of Financial Position [Member] | Appalachian Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[9]	(29,800,000)			(29,800,000)			(57,200,000)
Long-term Risk Management Assets	[9]	(3,900,000)			(3,900,000)			(2,200,000)
Total Assets	[9]	(33,700,000)			(33,700,000)			(59,400,000)
Current Risk Management Liabilities	[9]	(31,200,000)			(31,200,000)			(56,300,000)
Long-term Risk Management Liabilities	[9]	(4,100,000)			(4,100,000)			(2,200,000)
Total Liabilities	[9]	(35,300,000)			(35,300,000)			(58,500,000)
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	1,600,000			1,600,000			(900,000)
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]	(20,000,000.0)			(20,000,000.0)			(41,800,000)
Long-term Risk Management Assets	[9]	(2,600,000)			(2,600,000)			(1,400,000)
Total Assets	[9]	(22,600,000)			(22,600,000)			(43,200,000)
Current Risk Management Liabilities	[9]	(20,800,000)			(20,800,000)			(40,800,000)
Long-term Risk Management Liabilities	[9]	(2,700,000)			(2,700,000)			(1,500,000)
Total Liabilities	[9]	(23,500,000)			(23,500,000)			(42,300,000)
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	900,000			900,000			(900,000)
Gross Amounts Offset in the Statement of Financial Position [Member] | Ohio Power Co [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[9]	0			0			0
Long-term Risk Management Assets	[9]	0			0			0
Total Assets	[9]	0			0			0
Current Risk Management Liabilities	[9]	0			0			(600,000)
Long-term Risk Management Liabilities	[9]	0			0			0
Total Liabilities	[9]	0			0			(600,000)
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	0			0			600,000
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)			(200,000)			(500,000)
Long-term Risk Management Assets	[9]	0			0			0
Total Assets	[9]	(200,000)			(200,000)			(500,000)
Current Risk Management Liabilities	[9]	(200,000)			(200,000)			(700,000)
Long-term Risk Management Liabilities	[9]	0			0			0
Total Liabilities	[9]	(200,000)			(200,000)			(700,000)
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	0			0			200,000
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]	(400,000)			(400,000)			(800,000)
Long-term Risk Management Assets	[9]	0			0			0
Total Assets	[9]	(400,000)			(400,000)			(800,000)
Current Risk Management Liabilities	[9]	(400,000)			(400,000)			(1,100,000)
Long-term Risk Management Liabilities	[9]	0			0			0
Total Liabilities	[9]	(400,000)			(400,000)			(1,100,000)
Total MTM Derivative Contract Net Assets (Liabilities)	[9]	0			0			300,000
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	[10]	186,700,000			186,700,000			162,800,000
Long-term Risk Management Assets	[10]	299,000,000.0			299,000,000.0			254,000,000.0
Total Assets	[10]	485,700,000			485,700,000			416,800,000
Current Risk Management Liabilities	[10]	75,300,000			75,300,000			55,000,000.0
Long-term Risk Management Liabilities	[10]	298,600,000			298,600,000			263,400,000
Total Liabilities	[10]	373,900,000			373,900,000			318,400,000
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	111,800,000			111,800,000			98,400,000
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			0
Long-term Risk Management Assets	[10]	0			0			0
Total Assets	[10]	0			0			0
Current Risk Management Liabilities	[10]	300,000			300,000			200,000
Long-term Risk Management Liabilities	[10]	100,000			100,000			0
Total Liabilities	[10]	400,000			400,000			200,000
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	(400,000)			(400,000)			(200,000)
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	[10]	56,500,000			56,500,000			57,200,000
Long-term Risk Management Assets	[10]	200,000			200,000			900,000
Total Assets	[10]	56,700,000			56,700,000			58,100,000
Current Risk Management Liabilities	[10]	1,100,000			1,100,000			400,000
Long-term Risk Management Liabilities	[10]	300,000			300,000			200,000
Total Liabilities	[10]	1,400,000			1,400,000			600,000
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	55,300,000			55,300,000			57,500,000
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]	10,500,000			10,500,000			8,600,000
Long-term Risk Management Assets	[10]	100,000			100,000			600,000
Total Assets	[10]	10,600,000			10,600,000			9,200,000
Current Risk Management Liabilities	[10]	200,000			200,000			300,000
Long-term Risk Management Liabilities	[10]	0			0			100,000
Total Liabilities	[10]	200,000			200,000			400,000
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	10,400,000			10,400,000			8,800,000
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			0
Long-term Risk Management Assets	[10]	0			0			0
Total Assets	[10]	0			0			0
Current Risk Management Liabilities	[10]	7,200,000			7,200,000			5,800,000
Long-term Risk Management Liabilities	[10]	105,700,000			105,700,000			93,800,000
Total Liabilities	[10]	112,900,000			112,900,000			99,600,000
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	(112,900,000)			(112,900,000)			(99,600,000)
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]	21,700,000			21,700,000			10,400,000
Long-term Risk Management Assets	[10]	0			0			0
Total Assets	[10]	21,700,000			21,700,000			10,400,000
Current Risk Management Liabilities	[10]	300,000			300,000			1,000,000.0
Long-term Risk Management Liabilities	[10]	0			0			0
Total Liabilities	[10]	300,000			300,000			1,000,000.0
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	21,400,000			21,400,000			9,400,000
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]	9,400,000			9,400,000			4,800,000
Long-term Risk Management Assets	[10]	0			0			0
Total Assets	[10]	9,400,000			9,400,000			4,800,000
Current Risk Management Liabilities	[10]	1,700,000			1,700,000			400,000
Long-term Risk Management Liabilities	[10]	3,000,000.0			3,000,000.0			2,200,000
Total Liabilities	[10]	4,700,000			4,700,000			2,600,000
Total MTM Derivative Contract Net Assets (Liabilities)	[10]	$ 4,700,000			$ 4,700,000			$ 2,200,000
Power [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		424.3			424.3			371.1
Power [Member] | AEP Texas Inc. [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		0.0			0.0			0.0
Power [Member] | Appalachian Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		94.7			94.7			66.4
Power [Member] | Indiana Michigan Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		37.1			37.1			40.9
Power [Member] | Ohio Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		7.3			7.3			7.8
Power [Member] | Public Service Co Of Oklahoma [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		21.6			21.6			15.2
Power [Member] | Southwestern Electric Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MWh		6.9			6.9			4.5
Natural Gas [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		53.2			53.2			87.9
Natural Gas [Member] | AEP Texas Inc. [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		0.0			0.0			0.0
Natural Gas [Member] | Appalachian Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		0.0			0.0			4.0
Natural Gas [Member] | Indiana Michigan Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		0.0			0.0			2.3
Natural Gas [Member] | Ohio Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		0.0			0.0			0.0
Natural Gas [Member] | Public Service Co Of Oklahoma [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		0.0			0.0			0.0
Natural Gas [Member] | Southwestern Electric Power Co [Member]
Commodity:
Derivative, Energy Notional Amount | MMBTU		12.5			12.5			15.2
Heating Oil and Gasoline [Member]
Commodity:
Derivative, Volume Notional Amount | gal		8.4			8.4			7.4
Heating Oil and Gasoline [Member] | AEP Texas Inc. [Member]
Commodity:
Derivative, Volume Notional Amount | gal		1.8			1.8			1.5
Heating Oil and Gasoline [Member] | Appalachian Power Co [Member]
Commodity:
Derivative, Volume Notional Amount | gal		1.6			1.6			1.4
Heating Oil and Gasoline [Member] | Indiana Michigan Power Co [Member]
Commodity:
Derivative, Volume Notional Amount | gal		0.8			0.8			0.7
Heating Oil and Gasoline [Member] | Ohio Power Co [Member]
Commodity:
Derivative, Volume Notional Amount | gal		2.0			2.0			1.8
Heating Oil and Gasoline [Member] | Public Service Co Of Oklahoma [Member]
Commodity:
Derivative, Volume Notional Amount | gal		0.8			0.8			0.7
Heating Oil and Gasoline [Member] | Southwestern Electric Power Co [Member]
Commodity:
Derivative, Volume Notional Amount | gal		0.9			0.9			0.8
Interest Rate Contract [Member]
Commodity:
Derivative, Notional Amount		$ 140,100,000			$ 140,100,000			$ 37,700,000
Interest Rate Contract [Member] | AEP Texas Inc. [Member]
Commodity:
Derivative, Notional Amount		0			0			0
Interest Rate Contract [Member] | Appalachian Power Co [Member]
Commodity:
Derivative, Notional Amount		0			0			0
Interest Rate Contract [Member] | Indiana Michigan Power Co [Member]
Commodity:
Derivative, Notional Amount		0			0			0
Interest Rate Contract [Member] | Ohio Power Co [Member]
Commodity:
Derivative, Notional Amount		0			0			0
Interest Rate Contract [Member] | Public Service Co Of Oklahoma [Member]
Commodity:
Derivative, Notional Amount		0			0			0
Interest Rate Contract [Member] | Southwestern Electric Power Co [Member]
Commodity:
Derivative, Notional Amount		0			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		500,000		(700,000)	1,000,000.0		(9,400,000)
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		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		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		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		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		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		0
Generation and Marketing Revenues [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		21,000,000.0		19,300,000	27,200,000		31,700,000
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		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		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		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		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		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		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		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		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		200,000		(500,000)	200,000		(1,300,000)
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		200,000		(100,000)	500,000		(7,800,000)
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		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		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	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		400,000		300,000	1,600,000		8,300,000
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		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		300,000		300,000	1,400,000		7,300,000
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		0		0	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		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		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		0
Other Operation Expense [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts		(100,000)		500,000	(600,000)		1,300,000
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		0		100,000	(100,000)		300,000
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		(100,000)		100,000	(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		(100,000)		100,000	(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		(100,000)		100,000	(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		(100,000)		100,000	(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		0		100,000	(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		(200,000)		600,000	(600,000)		1,500,000
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		100,000	(100,000)		300,000
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		0		100,000	(100,000)		300,000
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		(100,000)		100,000	(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		0		100,000	(100,000)		300,000
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		0		100,000	0		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		0		100,000	(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)		(14,000,000.0)	(19,400,000)		29,200,000
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]	(200,000)		0	300,000		0
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]	200,000		0	400,000		0
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]	0		(3,500,000)	200,000		(300,000)
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]	(2,600,000)		(9,300,000)	(19,800,000)		31,800,000
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]	(100,000)		(600,000)	900,000		(600,000)
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]	(1,600,000)		(600,000)	(400,000)		(1,700,000)
Regulatory Liabilities [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	[11]	26,300,000		33,800,000	64,500,000		206,200,000
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]	0		0	0		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	[11]	10,000,000.0		24,000,000.0	(5,300,000)		127,300,000
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]	3,200,000		0	17,200,000		11,700,000
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]	0		0	0		600,000
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]	4,300,000		3,900,000	26,600,000		34,800,000
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]	4,500,000		1,500,000	22,900,000		7,600,000
Reclassification out of Accumulated Other Comprehensive Income [Member]
Interest Expense	[12]			400,000	500,000		900,000
Reclassification out of Accumulated Other Comprehensive Income [Member] | AEP Texas Inc. [Member]
Interest Expense	[12]			400,000	600,000		1,000,000.0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Appalachian Power Co [Member]
Interest Expense	[12]			(400,000)	(500,000)		(900,000)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Indiana Michigan Power Co [Member]
Interest Expense	[12]			400,000	1,000,000.0		1,500,000
Reclassification out of Accumulated Other Comprehensive Income [Member] | Southwestern Electric Power Co [Member]
Interest Expense	[12]			500,000	1,000,000.0		1,600,000
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Commodity [Member]
Interest Expense	[12]			0	0		0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Commodity [Member] | Appalachian Power Co [Member]
Interest Expense	[12]						0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate [Member]
Interest Expense	[12]			400,000	500,000		900,000
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate [Member] | AEP Texas Inc. [Member]
Interest Expense	[12]			400,000	600,000		1,000,000.0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate [Member] | Appalachian Power Co [Member]
Interest Expense	[12]			(400,000)	(500,000)		(900,000)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate [Member] | Indiana Michigan Power Co [Member]
Interest Expense	[12]			400,000	1,000,000.0		1,500,000
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate [Member] | Ohio Power Co [Member]
Interest Expense	[12]	(100,000)		(500,000)	(1,000,000.0)		(1,300,000)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate [Member] | Public Service Co Of Oklahoma [Member]
Interest Expense	[12]	$ 200,000		(200,000)	(500,000)		(900,000)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate [Member] | Southwestern Electric Power Co [Member]
Interest Expense	[12]			$ 500,000	1,000,000.0		$ 1,600,000
Apple Blossom and Black Oak [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate [Member]
Interest Expense					$ 6,000,000

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

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

[3] 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.’’

[4] The September 30, 2019 maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), is as follows: Level 2 matures $(6) million in 2019, $(8) million in periods 2020-2022 and $(1) million in periods 2025-2032; Level 3 matures $40 million in 2019, $114 million in periods 2020-2022, $26 million in periods 2023-2024 and $(4) million in periods 2025-2032.  Risk management commodity contracts are substantially comprised of power contracts.

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

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

[7] 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.”

[8] Includes $6 million related to AEP's investment in joint venture wind farms acquired as part of the purchase of Sempra Renewables LLC. See “Sempra Renewables LLC” section of Note 14 for additional information.

[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] Amounts reclassified to the referenced line item on the statements of income.