Revenue from Contracts with Customers (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2019		Jun. 30, 2018		Jun. 30, 2019		Jun. 30, 2018		Dec. 31, 2018
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		$ 3,573.6		$ 4,013.2		$ 7,630.4		$ 8,061.5
Total Revenues		3,573.6		4,013.2		7,630.4		8,061.5
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		1,163.6				1,163.6
Revenue Textuals [Abstract]
Revenue from Related Parties		0.0		0.0		0.0		0.0
2019 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		505.5				505.5
2020-2021 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		210.3				210.3
2022-2023 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		163.1				163.1
2023 and Forward [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		284.7				284.7
Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		2,705.1		3,022.1	[1]	5,807.9		6,092.7	[2]
Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		1,190.0		1,387.9		2,758.5		2,957.0
Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		805.1		872.0		1,627.2		1,674.3
Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		655.3		704.9		1,313.1		1,350.0
Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		54.7		57.3		109.1		111.4
Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		913.5		941.0		1,746.5		1,818.6
Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		512.8	[3]	344.8	[4]	767.8	[5]	703.9	[6]
Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		293.8	[7]	264.8	[8]	509.2	[9]	473.6	[10]
Marketing, Competitive Retail and Renewable [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		106.9		331.4		469.5		641.1
Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		59.3	[11]	94.3	[12]	137.4	[13]	185.0	[14]
Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		3,677.9		4,057.4		7,691.8		8,096.3
Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(104.3)		(44.2)		(61.4)		(34.8)
Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		72.7		109.3		137.7		157.4
Total Revenues		(9.4)	[11]	(8.6)	[12]	40.3	[13]	19.9	[14]
Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(94.9)	[11]	(35.6)	[12]	(101.7)	[13]	(54.7)	[14]
AEP Texas Inc. [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		438.0		388.3		828.7		759.9
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		193.5				193.5
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		20.4				20.4				$ 15.0
Revenue Textuals [Abstract]
Revenue from Related Parties		42.2		17.6		82.4		35.8
AEP Texas Inc. [Member] | 2019 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		193.5				193.5
AEP Texas Inc. [Member] | 2020-2021 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
AEP Texas Inc. [Member] | 2022-2023 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
AEP Texas Inc. [Member] | 2023 and Forward [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
AEP Texas Inc. [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		289.5		285.7	[15]	548.6		554.7	[16]
AEP Texas Inc. [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		142.0		143.2		262.9		274.8
AEP Texas Inc. [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		106.0		103.4		203.9		202.9
AEP Texas Inc. [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		33.6		31.8		66.6		62.7
AEP Texas Inc. [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		7.9		7.3		15.2		14.3
AEP Texas Inc. [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		98.5		78.0		184.3		156.0
AEP Texas Inc. [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[17]	0.0	[18]	0.0	[19]	0.0	[20]
AEP Texas Inc. [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		98.5	[21]	78.0	[22]	184.3	[23]	156.0	[24]
AEP Texas Inc. [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		7.8	[25]	7.2	[26]	14.7	[27]	14.3	[28]
AEP Texas Inc. [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		395.8		370.9		747.6		725.0
AEP Texas Inc. [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		42.2		17.4		81.1		34.9
AEP Texas Inc. [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.7		0.6		1.4		1.6
Total Revenues		41.0	[29]	17.2	[30]	80.8	[31]	35.0	[32]
AEP Texas Inc. [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		1.2	[29]	0.2	[30]	0.3	[31]	(0.1)	[32]
AEP Transmission Co [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		266.9		200.1	[33]	510.4		391.8	[34]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		451.6				451.6
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		84.2				84.2				61.0
Revenue Textuals [Abstract]
Revenue from Related Parties		209.1		144.7		402.3		305.4
AEP Transmission Co [Member] | Short-term Contract with Customer [Member]
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		82.8				82.8				58.6
AEP Transmission Co [Member] | 2019 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		451.6				451.6
AEP Transmission Co [Member] | 2020-2021 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
AEP Transmission Co [Member] | 2022-2023 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
AEP Transmission Co [Member] | 2023 and Forward [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
AEP Transmission Co [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0	[15],[33]	0.0		0.0	[16],[34]
AEP Transmission Co [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0	[33]	0.0		0.0	[34]
AEP Transmission Co [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0	[33]	0.0		0.0	[34]
AEP Transmission Co [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0	[33]	0.0		0.0	[34]
AEP Transmission Co [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0	[33]	0.0		0.0	[34]
AEP Transmission Co [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		276.8		221.4	[33]	518.9		406.3	[34]
AEP Transmission Co [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[17]	0.0	[18],[33]	0.0	[19]	0.0	[20],[34]
AEP Transmission Co [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		276.8	[21]	221.4	[22],[33]	518.9	[23]	406.3	[24],[34]
Revenue Textuals [Abstract]
Revenue from Related Parties		198.0		104.0		393.0		241.0
AEP Transmission Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		5.0	[25]	6.4	[26],[33]	8.1	[27]	8.5	[28],[34]
AEP Transmission Co [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		281.8		227.8	[33]	527.0		414.8	[34]
AEP Transmission Co [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(14.9)		(27.7)	[33]	(16.6)		(23.0)	[34]
AEP Transmission Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.1
Total Revenues		0.0	[29]	0.0	[30],[33]	0.0	[31]	0.0	[32],[34]
AEP Transmission Co [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(14.9)	[29]	(27.7)	[30],[33]	(16.6)	[31]	(23.0)	[32],[34]
Appalachian Power Co [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		655.8		667.0		1,448.6		1,487.4
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		142.7				142.7
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		54.9				54.9				73.4
Revenue Textuals [Abstract]
Revenue from Related Parties		46.3		46.4		98.0		95.8
Appalachian Power Co [Member] | Short-term Contract with Customer [Member]
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		40.4				40.4				52.5
Appalachian Power Co [Member] | 2019 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		72.9				72.9
Appalachian Power Co [Member] | 2020-2021 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		32.7				32.7
Appalachian Power Co [Member] | 2022-2023 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		25.5				25.5
Appalachian Power Co [Member] | 2023 and Forward [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		11.6				11.6
Appalachian Power Co [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		551.6		594.2	[15]	1,233.4		1,321.7	[16]
Appalachian Power Co [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		256.5		282.3		629.0		696.3
Appalachian Power Co [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		132.1		140.6		274.3		287.2
Appalachian Power Co [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		144.6		152.5		292.1		299.8
Appalachian Power Co [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		18.4		18.8		38.0		38.4
Appalachian Power Co [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		87.9		71.3		181.1		158.9
Appalachian Power Co [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		62.2	[17]	56.8	[18]	129.7	[19]	119.6	[20]
Revenue Textuals [Abstract]
Revenue from Related Parties		30.0		29.0		64.0		69.0
Appalachian Power Co [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		25.7	[21]	14.5	[22]	51.4	[23]	39.3	[24]
Appalachian Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		16.1	[25]	15.1	[26]	29.5	[27]	26.3	[28]
Appalachian Power Co [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		655.6		680.6		1,444.0		1,506.9
Appalachian Power Co [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		0.2		(13.6)		4.6		(19.5)
Appalachian Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		3.6		1.8		6.0		5.3
Total Revenues		0.0	[29]	0.0	[30]	0.0	[31]	0.0	[32]
Appalachian Power Co [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		0.2	[29]	(13.6)	[30]	4.6	[31]	(19.5)	[32]
Indiana Michigan Power Co [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		543.1		589.7		1,157.4		1,166.5
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		36.5				36.5
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		47.3				47.3				75.0
Revenue Textuals [Abstract]
Revenue from Related Parties		2.3		10.8		4.6		15.5
Indiana Michigan Power Co [Member] | Short-term Contract with Customer [Member]
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		14.5				14.5				35.3
Indiana Michigan Power Co [Member] | 2019 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		14.4				14.4
Indiana Michigan Power Co [Member] | 2020-2021 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		8.9				8.9
Indiana Michigan Power Co [Member] | 2022-2023 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		8.8				8.8
Indiana Michigan Power Co [Member] | 2023 and Forward [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		4.4				4.4
Indiana Michigan Power Co [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		390.5		432.5	[15]	870.4		865.3	[16]
Indiana Michigan Power Co [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		142.2		163.0		360.6		352.0
Indiana Michigan Power Co [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		111.8		122.1		233.1		231.8
Indiana Michigan Power Co [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		134.8		145.9		273.2		277.8
Indiana Michigan Power Co [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		1.7		1.5		3.5		3.7
Indiana Michigan Power Co [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		119.5		146.0		237.7		266.8
Indiana Michigan Power Co [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		113.4	[17]	142.1	[18]	225.3	[19]	256.1	[20]
Indiana Michigan Power Co [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		6.1	[21]	3.9	[22]	12.4	[23]	10.7	[24]
Indiana Michigan Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		28.6	[25]	25.9	[26]	49.6	[27]	48.6	[28]
Indiana Michigan Power Co [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		538.6		604.4		1,157.7		1,180.7
Indiana Michigan Power Co [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		4.5		(14.7)		(0.3)		(14.2)
Indiana Michigan Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		2.5		2.4		4.5		7.4
Total Revenues		0.0	[29]	(14.2)	[30]	0.0	[31]	(8.7)	[32]
Revenue Textuals [Abstract]
Revenue from Related Parties		23.0		26.0		38.0		41.0
Indiana Michigan Power Co [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		4.5	[29]	(0.5)	[30]	(0.3)	[31]	(5.5)	[32]
Ohio Power Co [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		606.6		748.8		1,443.4		1,539.7
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		43.1				43.1
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		51.9				51.9				70.8
Revenue Textuals [Abstract]
Revenue from Related Parties		1.7		11.5		9.2		14.6
Ohio Power Co [Member] | Short-term Contract with Customer [Member]
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		30.8				30.8				46.1
Ohio Power Co [Member] | 2019 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		35.6				35.6
Ohio Power Co [Member] | 2020-2021 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		7.5				7.5
Ohio Power Co [Member] | 2022-2023 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Ohio Power Co [Member] | 2023 and Forward [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Ohio Power Co [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		551.4		710.4	[15]	1,326.6		1,432.8	[16]
Ohio Power Co [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		288.3		388.1		759.9		824.9
Ohio Power Co [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		182.7		215.7		393.2		410.3
Ohio Power Co [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		77.1		103.3		166.8		191.1
Ohio Power Co [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		3.3		3.3		6.7		6.5
Ohio Power Co [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		14.4		12.0		28.3		28.0
Ohio Power Co [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[17]	0.0	[18]	0.0	[19]	0.0	[20]
Ohio Power Co [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		14.4	[21]	12.0	[22]	28.3	[23]	28.0	[24]
Ohio Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		33.3	[25]	38.9	[26]	72.3	[27]	81.2	[28]
Ohio Power Co [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		599.1		761.3		1,427.2		1,542.0
Ohio Power Co [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		7.5		(12.5)		16.2		(2.3)
Ohio Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		2.6		1.4		5.4		2.9
Total Revenues		1.5	[29]	4.1	[30]	6.6	[31]	8.0	[32]
Ohio Power Co [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		6.0	[29]	(16.6)	[30]	9.6	[31]	(10.3)	[32]
Public Service Co Of Oklahoma [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		348.1		398.3		680.9		735.1
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		8.6				8.6
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		36.5				36.5				26.2
Revenue Textuals [Abstract]
Revenue from Related Parties		2.1		1.5		3.7		2.6
Public Service Co Of Oklahoma [Member] | Short-term Contract with Customer [Member]
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		24.5				24.5				12.4
Public Service Co Of Oklahoma [Member] | 2019 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		8.6				8.6
Public Service Co Of Oklahoma [Member] | 2020-2021 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Public Service Co Of Oklahoma [Member] | 2022-2023 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Public Service Co Of Oklahoma [Member] | 2023 and Forward [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Public Service Co Of Oklahoma [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		352.2		374.2	[15]	662.0		687.0	[16]
Public Service Co Of Oklahoma [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		147.7		169.4		287.7		310.6
Public Service Co Of Oklahoma [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		101.3		105.2		182.1		189.3
Public Service Co Of Oklahoma [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		83.0		77.3		154.0		146.4
Public Service Co Of Oklahoma [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		20.2		22.3		38.2		40.7
Public Service Co Of Oklahoma [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		21.3		13.6		39.7		30.1
Public Service Co Of Oklahoma [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		5.8	[17]	8.3	[18]	14.4	[19]	14.2	[20]
Public Service Co Of Oklahoma [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		15.5	[21]	5.3	[22]	25.3	[23]	15.9	[24]
Public Service Co Of Oklahoma [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		5.8	[25]	4.9	[26]	11.6	[27]	9.1	[28]
Public Service Co Of Oklahoma [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		379.3		392.7		713.3		726.2
Public Service Co Of Oklahoma [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(31.2)		5.6		(32.4)		8.9
Public Service Co Of Oklahoma [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		1.4		1.5		3.4		2.1
Total Revenues		0.0	[29]	0.0	[30]	0.0	[31]	0.0	[32]
Public Service Co Of Oklahoma [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(31.2)	[29]	5.6	[30]	(32.4)	[31]	8.9	[32]
Southwestern Electric Power Co [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		375.5		457.1		796.6		876.5
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		20.0				20.0
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		56.5				56.5				28.8
Revenue Textuals [Abstract]
Revenue from Related Parties		6.4		5.4		12.8		11.5
Southwestern Electric Power Co [Member] | Short-term Contract with Customer [Member]
Assets, Current [Abstract]
Affiliated Companies - Contracts with Customers		45.9				45.9				$ 16.3
Southwestern Electric Power Co [Member] | 2019 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		20.0				20.0
Southwestern Electric Power Co [Member] | 2020-2021 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Southwestern Electric Power Co [Member] | 2022-2023 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Southwestern Electric Power Co [Member] | 2023 and Forward [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Southwestern Electric Power Co [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		339.7		371.4	[15]	676.9		699.1	[16]
Southwestern Electric Power Co [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		140.7		158.2		280.8		298.3
Southwestern Electric Power Co [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		113.1		123.9		226.8		232.2
Southwestern Electric Power Co [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		83.7		87.2		164.9		164.4
Southwestern Electric Power Co [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		2.2		2.1		4.4		4.2
Southwestern Electric Power Co [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		68.6		77.5		150.0		163.4
Southwestern Electric Power Co [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		44.8	[17]	55.7	[18]	102.0	[19]	115.6	[20]
Southwestern Electric Power Co [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		23.8	[21]	21.8	[22]	48.0	[23]	47.8	[24]
Southwestern Electric Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		5.3	[25]	5.3	[26]	13.1	[27]	11.4	[28]
Southwestern Electric Power Co [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		413.6		454.2		840.0		873.9
Southwestern Electric Power Co [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(38.1)		2.9		(43.4)		2.6
Southwestern Electric Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.3		0.3		0.7		0.6
Total Revenues		0.0	[29]	0.0	[30]	0.0	[31]	0.0	[32]
Southwestern Electric Power Co [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(38.1)	[29]	2.9	[30]	(43.4)	[31]	2.6	[32]
Consolidation Eliminations [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Total Revenues		(311.3)		(169.8)		(643.5)		(426.5)
Revenue Textuals [Abstract]
Revenue from Related Parties		(311.3)		(169.8)		(643.5)		(426.5)
Consolidation Eliminations [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(3.3)		0.0	[1]	(1.5)		0.0	[2]
Consolidation Eliminations [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Consolidation Eliminations [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Consolidation Eliminations [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(3.3)		0.0		(1.5)		0.0
Consolidation Eliminations [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Consolidation Eliminations [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(166.4)		(125.9)		(457.7)		(335.8)
Consolidation Eliminations [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		7.2	[3]	(26.6)	[4]	(71.3)	[5]	(56.7)	[6]
Consolidation Eliminations [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(173.6)	[7]	(99.3)	[8]	(386.4)	[9]	(279.1)	[10]
Consolidation Eliminations [Member] | Marketing, Competitive Retail and Renewable [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Consolidation Eliminations [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(35.3)	[11]	(22.6)	[12]	(71.4)	[13]	(47.7)	[14]
Consolidation Eliminations [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(205.0)		(148.5)		(530.6)		(383.5)
Consolidation Eliminations [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(106.3)		(21.3)		(112.9)		(43.0)
Consolidation Eliminations [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(69.4)	[11]	(21.3)	[12]	(69.4)	[13]	(43.0)	[14]
Consolidation Eliminations [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(36.9)	[11]	0.0	[12]	(43.5)	[13]	0.0	[14]
Consolidation Eliminations [Member] | AEP Transmission Co [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Total Revenues		0.0		0.0		0.0		0.0
Revenue Textuals [Abstract]
Revenue from Related Parties		0.0		0.0		0.0		0.0
Consolidation Eliminations [Member] | AEP Transmission Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Vertically Integrated Utilities [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		2,123.8		2,349.0		4,527.1		4,757.0
Revenue Textuals [Abstract]
Revenue from Related Parties		7.4		8.3		38.4		34.8
Vertically Integrated Utilities [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		1,865.3		2,026.0	[1]	3,934.3		4,105.7	[2]
Vertically Integrated Utilities [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		755.0		857.0		1,737.4		1,858.2
Vertically Integrated Utilities [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		517.5		551.9		1,028.7		1,059.9
Vertically Integrated Utilities [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		549.2		570.7		1,081.3		1,097.3
Vertically Integrated Utilities [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		43.6		46.4		86.9		90.3
Vertically Integrated Utilities [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		270.0		305.9		568.2		597.9
Vertically Integrated Utilities [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		205.9	[3]	245.3	[4]	430.6	[5]	462.3	[6]
Vertically Integrated Utilities [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		64.1	[7]	60.6	[8]	137.6	[9]	135.6	[10]
Vertically Integrated Utilities [Member] | Marketing, Competitive Retail and Renewable [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Vertically Integrated Utilities [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		42.0	[11]	41.6	[12]	81.5	[13]	81.5	[14]
Vertically Integrated Utilities [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		2,177.3		2,373.5		4,584.0		4,785.1
Vertically Integrated Utilities [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(53.5)		(24.5)		(56.9)		(28.1)
Vertically Integrated Utilities [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		0.0	[11]	(14.2)	[12]	0.0	[13]	(8.7)	[14]
Vertically Integrated Utilities [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(53.5)	[11]	(10.3)	[12]	(56.9)	[13]	(19.4)	[14]
Transmission And Distribution Utilities [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		1,045.7		1,137.0		2,267.7		2,299.4
Revenue Textuals [Abstract]
Revenue from Related Parties		44.1		9.1		86.3		30.3
Transmission And Distribution Utilities [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		843.1		996.1	[1]	1,875.1		1,987.0	[2]
Transmission And Distribution Utilities [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		435.0		530.9		1,021.1		1,098.8
Transmission And Distribution Utilities [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		287.6		320.1		598.5		614.4
Transmission And Distribution Utilities [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		109.4		134.2		233.3		252.7
Transmission And Distribution Utilities [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		11.1		10.9		22.2		21.1
Transmission And Distribution Utilities [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		113.5		90.5		213.1		184.6
Transmission And Distribution Utilities [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[3]	0.0	[4]	0.0	[5]	0.0	[6]
Transmission And Distribution Utilities [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		113.5	[7]	90.5	[8]	213.1	[9]	184.6	[10]
Transmission And Distribution Utilities [Member] | Marketing, Competitive Retail and Renewable [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Transmission And Distribution Utilities [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		38.7	[11]	45.5	[12]	84.7	[13]	95.2	[14]
Transmission And Distribution Utilities [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		995.3		1,132.1		2,172.9		2,266.8
Transmission And Distribution Utilities [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		50.4		4.9		94.8		32.6
Transmission And Distribution Utilities [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		39.0	[11]	21.3	[12]	78.4	[13]	43.0	[14]
Transmission And Distribution Utilities [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		11.4	[11]	(16.4)	[12]	16.4	[13]	(10.4)	[14]
AEP Transmission Holdco [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		278.9		212.5		535.3		418.0
AEP Transmission Holdco [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0	[1]	0.0		0.0	[2]
AEP Transmission Holdco [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
AEP Transmission Holdco [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
AEP Transmission Holdco [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
AEP Transmission Holdco [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
AEP Transmission Holdco [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		289.8		213.0		544.9		432.5
AEP Transmission Holdco [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[3]	0.0	[4]	0.0	[5]	0.0	[6]
AEP Transmission Holdco [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		289.8	[7]	213.0	[8]	544.9	[9]	432.5	[10]
Revenue Textuals [Abstract]
Revenue from Related Parties		201.0		134.0		399.0		297.0
AEP Transmission Holdco [Member] | Marketing, Competitive Retail and Renewable [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
AEP Transmission Holdco [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		5.0	[11]	8.4	[12]	8.1	[13]	10.4	[14]
AEP Transmission Holdco [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		294.8		221.4		553.0		442.9
AEP Transmission Holdco [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(15.9)		(8.9)		(17.7)		(24.9)
AEP Transmission Holdco [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		0.0	[11]	0.0	[12]	0.0	[13]	0.0	[14]
AEP Transmission Holdco [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(15.9)	[11]	(8.9)	[12]	(17.7)	[13]	(24.9)	[14]
Generation And Marketing [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		412.7		460.7		894.5		965.8
Revenue Textuals [Abstract]
Revenue from Related Parties		29.8		25.4		71.9		53.0
Generation And Marketing [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0	[1]	0.0		0.0	[2]
Generation And Marketing [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Generation And Marketing [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Generation And Marketing [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Generation And Marketing [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Generation And Marketing [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		406.6		457.5		878.0		939.4
Generation And Marketing [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		299.7	[3]	126.1	[4]	408.5	[5]	298.3	[6]
Revenue Textuals [Abstract]
Revenue from Related Parties		34.0		25.0		71.0		52.0
Generation And Marketing [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[7]	0.0	[8]	0.0	[9]	0.0	[10]
Generation And Marketing [Member] | Marketing, Competitive Retail and Renewable [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		106.9		331.4		469.5		641.1
Generation And Marketing [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(12.6)	[11]	0.1	[12]	(10.3)	[13]	2.3	[14]
Generation And Marketing [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		394.0		457.6		867.7		941.7
Generation And Marketing [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		18.7		3.1		26.8		24.1
Generation And Marketing [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		18.7	[11]	3.1	[12]	26.8	[13]	24.1	[14]
Generation And Marketing [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		0.0	[11]	0.0	[12]	0.0	[13]	0.0	[14]
Other Segments [Member]
Disaggregation of Revenue [Abstract]
Total Revenues	[35]	23.8		23.8		49.3		47.8
Revenue Textuals [Abstract]
Revenue from Related Parties		20.9		18.0	[35]	42.6		35.0	[35]
Other Segments [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0	[1]	0.0		0.0	[2]
Other Segments [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Other Segments [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Other Segments [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Other Segments [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Other Segments [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Other Segments [Member] | Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[3]	0.0	[4]	0.0	[5]	0.0	[6]
Other Segments [Member] | Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[7]	0.0	[8]	0.0	[9]	0.0	[10]
Other Segments [Member] | Marketing, Competitive Retail and Renewable [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Other Segments [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		21.5	[11]	21.3	[12]	44.8	[13]	43.3	[14]
Other Segments [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		21.5		21.3		44.8		43.3
Other Segments [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		2.3		2.5		4.5		4.5
Other Segments [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		2.9		5.8	[35]	6.7		12.8	[35]
Total Revenues		2.3	[11]	2.5	[12]	4.5	[13]	4.5	[14]
Other Segments [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		$ 0.0	[11]	$ 0.0	[12]	$ 0.0	[13]	$ 0.0	[14]

[1] 2018 amounts have been revised to reflect the reclassification of certain customer accounts between Retail classes. This reclassification did not impact previously reported Total Retail Revenues. Management concluded that these prior period disclosure only errors were immaterial individually and in the aggregate.

[2] 2018 amounts have been revised to reflect the reclassification of certain customer accounts between Retail classes. This reclassification did not impact previously reported Total Retail Revenues. Management concluded that these prior period disclosure only errors were immaterial individually and in the aggregate.

[3] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for Generation & Marketing is $34 million. The remaining affiliated amounts are immaterial.

[4] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for Generation & Marketing is $25 million. The remaining affiliated amounts are immaterial.

[5] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for Generation & Marketing is $71 million. The remaining affiliated amounts are immaterial.

[6] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for Generation & Marketing is $52 million. The remaining affiliated amounts are immaterial

[7] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEP Transmission Holdco is $201 million. The remaining affiliated amounts are immaterial.

[8] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEP Transmission Holdco is $134 million. The remaining affiliated amounts are immaterial.

[9] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEP Transmission Holdco is $399 million. The remaining affiliated amounts are immaterial.

[10] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEP Transmission Holdco is $297 million. The remaining affiliated amounts are immaterial.

[11] Amounts include affiliated and nonaffiliated revenues.

[12] Amounts include affiliated and nonaffiliated revenues.

[13] Amounts include affiliated and nonaffiliated revenues.

[14] Amounts include affiliated and nonaffiliated revenues.

[15] 2018 amounts have been revised to reflect the reclassification of certain customer accounts between Retail classes. This reclassification did not impact previously reported Total Retail Revenues. Management concluded that these prior period disclosure only errors were immaterial individually and in the aggregate.

[16] 2018 amounts have been revised to reflect the reclassification of certain customer accounts between Retail classes. This reclassification did not impact previously reported Total Retail Revenues. Management concluded that these prior period disclosure only errors were immaterial individually and in the aggregate.

[17] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for APCo is $30 million primarily relating to the PPA with Kingsport. The remaining affiliated amounts are immaterial.

[18] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for APCo is $29 million primarily relating to the PPA with Kingsport. The remaining affiliated amounts are immaterial.

[19] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for APCo is $64 million primarily relating to the PPA with Kingsport. The remaining affiliated amounts are immaterial.

[20] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for APCo is $69 million primarily relating to the PPA with Kingsport. The remaining affiliated amounts are immaterial.

[21] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEPTCo is $198 million. The remaining affiliated amounts are immaterial.

[22] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEPTCo is $104 million. The remaining affiliated amounts are immaterial.

[23] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEPTCo is $393 million. The remaining affiliated amounts are immaterial.

[24] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEPTCo is $241 million. The remaining affiliated amounts are immaterial.

[25] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for I&M is $23 million primarily relating to the barging, urea transloading and other transportation services. The remaining affiliated amounts are immaterial.

[26] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for I&M is $26 million primarily relating to the barging, urea transloading and other transportation services. The remaining affiliated amounts are immaterial.

[27] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for I&M is $38 million primarily relating to barging, urea transloading and other transportation services. The remaining affiliated amounts are immaterial.

[28] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for I&M is $41 million primarily relating to barging, urea transloading and other transportation services. The remaining affiliated amounts are immaterial.

[29] Amounts include affiliated and nonaffiliated revenues.

[30] Amounts include affiliated and nonaffiliated revenues.

[31] Amounts include affiliated and nonaffiliated revenues.

[32] Amounts include affiliated and nonaffiliated revenues.

[33] These amounts presented reflect the revisions made to AEPTCo’s previously issued financial statement. See the “revisions to Previously Issued Financial Statements” section of Note 1 for additional information.

[34] The amounts presented reflect the revisions made to AEPTCo’s previously issued financial statements. For additional details on revisions made to AEPTCo’s financial statements, see Note 1- Significant Accounting Matters.

[35] Corporate and Other primarily includes the purchasing of receivables from certain AEP utility subsidiaries. This segment also includes Parent’s guarantee revenue received from affiliates, investment income, interest income and interest expense and other nonallocated costs.