Revenue from Contracts with Customers (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2020		Jun. 30, 2019		Jun. 30, 2020		Jun. 30, 2019		Dec. 31, 2019
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		$ 3,494.0		$ 3,573.6		$ 7,241.5		$ 7,630.4
Total Revenues		3,494.0		3,573.6		7,241.5		7,630.4
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		1,096.6				1,096.6
Revenue Textuals [Abstract]
Revenue from Related Parties		0.0		0.0		0.0		0.0
2020 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		527.5				527.5
2021-2022 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		185.4				185.4
2023-2024 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		160.3				160.3
2024 and Forward [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		223.4				223.4
Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		2,677.7		2,705.1		5,547.9		5,807.9
Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		1,315.2		1,190.0		2,751.6		2,758.5
Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		730.8		805.1		1,497.1		1,627.2
Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		584.5		655.3		1,200.3		1,313.1
Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		47.2		54.7		98.9		109.1
Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		798.9		913.5		1,564.1		1,746.5
Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		180.1		512.8	[1]	364.6		767.8	[2]
Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		300.9	[3]	293.8	[4]	541.7	[5]	509.2	[6]
Renewable Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		17.4	[7]	11.1	[8]	34.0	[9]	18.8	[10]
Retail, Trading and Marketing Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		300.5	[11]	95.8	[8]	623.8	[12]	450.7	[10]
Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		82.6	[7]	59.3	[8]	154.1	[9]	137.4	[10]
Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		3,559.2		3,677.9		7,266.1		7,691.8
Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(65.2)		(104.3)		(24.6)		(61.4)
Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(64.1)	[7]	(94.9)	[8]	(43.4)	[9]	(101.7)	[10]
Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		72.1		72.7		143.0		137.7
Total Revenues		(1.1)	[7]	(9.4)	[8]	18.8	[9]	40.3	[10]
AEP Texas Inc. [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		401.5		438.0		825.1		828.7
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		216.3				216.3
Revenue Textuals [Abstract]
Revenue from Related Parties		16.9		42.2		48.0		82.4
Affiliated Companies		50.3				50.3				$ 10.1
AEP Texas Inc. [Member] | 2020 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		216.3				216.3
AEP Texas Inc. [Member] | 2021-2022 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
AEP Texas Inc. [Member] | 2023-2024 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
AEP Texas Inc. [Member] | 2024 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		282.3		289.5		571.6		548.6
AEP Texas Inc. [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		149.6		142.0		282.5		262.9
AEP Texas Inc. [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		94.4		106.0		207.2		203.9
AEP Texas Inc. [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		31.3		33.6		66.5		66.6
AEP Texas Inc. [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		7.0		7.9		15.4		15.2
AEP Texas Inc. [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		91.7		98.5		188.6		184.3
AEP Texas Inc. [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[13]	0.0	[14]	0.0	[15]	0.0	[16]
AEP Texas Inc. [Member] | Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		91.7	[17]	98.5	[18]	188.6	[19]	184.3	[20]
AEP Texas Inc. [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		10.3	[21]	7.8	[22]	18.2	[23]	14.7	[24]
AEP Texas Inc. [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		384.3		395.8		778.4		747.6
AEP Texas Inc. [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		17.2		42.2		46.7		81.1
AEP Texas Inc. [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		1.1	[25]	1.2	[26]	0.4	[27]	0.3	[28]
AEP Texas Inc. [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		1.1		0.7		2.0		1.4
Total Revenues		16.1	[25]	41.0	[26]	46.3	[27]	80.8	[28]
AEP Transmission Co [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		238.1		266.9		533.7		510.4
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		549.6				549.6
Revenue Textuals [Abstract]
Revenue from Related Parties		177.7		209.1		411.4		402.3
Affiliated Companies		124.7				124.7				66.1
AEP Transmission Co [Member] | Short-term Contract with Customer [Member]
Revenue Textuals [Abstract]
Affiliated Companies		80.1				80.1				65.9
AEP Transmission Co [Member] | 2020 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		549.6				549.6
AEP Transmission Co [Member] | 2021-2022 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
AEP Transmission Co [Member] | 2023-2024 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
AEP Transmission Co [Member] | 2024 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		0.0		0.0
AEP Transmission Co [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
AEP Transmission Co [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
AEP Transmission Co [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
AEP Transmission Co [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
AEP Transmission Co [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		298.7		276.8		596.9		518.9
AEP Transmission Co [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[13]	0.0	[14]	0.0	[15]	0.0	[16]
AEP Transmission Co [Member] | Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		298.7	[17]	276.8	[18]	596.9	[19]	518.9	[20]
Revenue Textuals [Abstract]
Revenue from Related Parties		237.0		198.0		472.0		393.0
AEP Transmission Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		11.1	[21]	5.0	[22]	14.5	[23]	8.1	[24]
AEP Transmission Co [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		309.8		281.8		611.4		527.0
AEP Transmission Co [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(71.7)		(14.9)		(77.7)		(16.6)
AEP Transmission Co [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(71.7)	[25]	(14.9)	[26]	(77.7)	[27]	(16.6)	[28]
AEP Transmission Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.6		0.0
Total Revenues		0.0	[25]	0.0	[26]	0.0	[27]	0.0	[28]
Appalachian Power Co [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		637.5		655.8		1,386.9		1,448.6
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		150.4				150.4
Revenue Textuals [Abstract]
Revenue from Related Parties		30.8		46.3		80.5		98.0
Affiliated Companies		117.6				117.6				64.3
Appalachian Power Co [Member] | Short-term Contract with Customer [Member]
Revenue Textuals [Abstract]
Affiliated Companies		48.5				48.5				47.3
Appalachian Power Co [Member] | 2020 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		80.2				80.2
Appalachian Power Co [Member] | 2021-2022 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		33.1				33.1
Appalachian Power Co [Member] | 2023-2024 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		25.5				25.5
Appalachian Power Co [Member] | 2024 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		542.5		551.6		1,191.3		1,233.4
Appalachian Power Co [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		272.7		256.5		630.2		629.0
Appalachian Power Co [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		119.9		132.1		252.2		274.3
Appalachian Power Co [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		134.5		144.6		275.6		292.1
Appalachian Power Co [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		15.4		18.4		33.3		38.0
Appalachian Power Co [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		91.2		87.9		175.7		181.1
Appalachian Power Co [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		60.9	[13]	62.2	[14]	115.0	[15]	129.7	[16]
Appalachian Power Co [Member] | Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		30.3	[17]	25.7	[18]	60.7	[19]	51.4	[20]
Appalachian Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		13.5	[21]	16.1	[22]	30.7	[23]	29.5	[24]
Appalachian Power Co [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		647.2		655.6		1,397.7		1,444.0
Appalachian Power Co [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(9.7)		0.2		(10.8)		4.6
Appalachian Power Co [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(9.7)	[25]	0.2	[26]	(10.8)	[27]	4.6	[28]
Appalachian Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		2.7		3.6		5.4		6.0
Total Revenues		0.0	[25]	0.0	[26]	0.0	[27]	0.0	[28]
Appalachian Power Co [Member] | Fuel and Other Consumables Used for Electric Generation [Member]
Revenue Textuals [Abstract]
Revenue from Related Parties		24.0		30.0		57.0		64.0
Indiana Michigan Power Co [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		546.6		543.1		1,116.9		1,157.4
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		41.4				41.4
Revenue Textuals [Abstract]
Revenue from Related Parties		4.9		2.3		7.8		4.6
Affiliated Companies		79.5				79.5				53.7
Indiana Michigan Power Co [Member] | Short-term Contract with Customer [Member]
Revenue Textuals [Abstract]
Affiliated Companies		29.9				29.9				37.1
Indiana Michigan Power Co [Member] | 2020 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		17.3				17.3
Indiana Michigan Power Co [Member] | 2021-2022 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		10.9				10.9
Indiana Michigan Power Co [Member] | 2023-2024 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		8.8				8.8
Indiana Michigan Power Co [Member] | 2024 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		437.2		390.5		900.3		870.4
Indiana Michigan Power Co [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		186.9		142.2		388.2		360.6
Indiana Michigan Power Co [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		118.0		111.8		240.2		233.1
Indiana Michigan Power Co [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		130.7		134.8		268.5		273.2
Indiana Michigan Power Co [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		1.6		1.7		3.4		3.5
Indiana Michigan Power Co [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		82.9		119.5		168.7		237.7
Indiana Michigan Power Co [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		75.6	[13]	113.4	[14]	154.0	[15]	225.3	[16]
Indiana Michigan Power Co [Member] | Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		7.3	[17]	6.1	[18]	14.7	[19]	12.4	[20]
Indiana Michigan Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		21.9	[21]	28.6	[22]	42.9	[23]	49.6	[24]
Indiana Michigan Power Co [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		542.0		538.6		1,111.9		1,157.7
Indiana Michigan Power Co [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		4.6		4.5		5.0		(0.3)
Indiana Michigan Power Co [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		4.6	[25]	4.5	[26]	5.0	[27]	(0.3)	[28]
Indiana Michigan Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		1.0		2.5		2.5		4.5
Total Revenues		0.0	[25]	0.0	[26]	0.0	[27]	0.0	[28]
Revenue Textuals [Abstract]
Revenue from Related Parties		18.0		23.0		34.0		38.0
Ohio Power Co [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		640.4		606.6		1,330.7		1,443.4
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		38.4				38.4
Revenue Textuals [Abstract]
Revenue from Related Parties		16.3		1.7		24.7		9.2
Affiliated Companies		82.0				82.0				59.3
Ohio Power Co [Member] | Short-term Contract with Customer [Member]
Revenue Textuals [Abstract]
Affiliated Companies		37.8				37.8				33.9
Ohio Power Co [Member] | 2020 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		33.1				33.1
Ohio Power Co [Member] | 2021-2022 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		5.3				5.3
Ohio Power Co [Member] | 2023-2024 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Ohio Power Co [Member] | 2024 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		577.5		551.4		1,196.0		1,326.6
Ohio Power Co [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		344.8		288.3		733.2		759.9
Ohio Power Co [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		162.1		182.7		326.1		393.2
Ohio Power Co [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		67.3		77.1		130.0		166.8
Ohio Power Co [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		3.3		3.3		6.7		6.7
Ohio Power Co [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		16.8		14.4		33.9		28.3
Ohio Power Co [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[13]	0.0	[14]	0.0	[15]	0.0	[16]
Ohio Power Co [Member] | Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		16.8	[17]	14.4	[18]	33.9	[19]	28.3	[20]
Ohio Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		22.7	[21]	33.3	[22]	51.3	[23]	72.3	[24]
Ohio Power Co [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		617.0		599.1		1,281.2		1,427.2
Ohio Power Co [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		23.4		7.5		49.5		16.2
Ohio Power Co [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		19.6	[25]	6.0	[26]	39.6	[27]	9.6	[28]
Ohio Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		2.3		2.6		5.0		5.4
Total Revenues		3.8	[25]	1.5	[26]	9.9	[27]	6.6	[28]
Public Service Co Of Oklahoma [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		308.6		348.1		605.9		680.9
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		7.5				7.5
Revenue Textuals [Abstract]
Revenue from Related Parties		1.3		2.1		2.4		3.7
Affiliated Companies		41.0				41.0				20.6
Public Service Co Of Oklahoma [Member] | Short-term Contract with Customer [Member]
Revenue Textuals [Abstract]
Affiliated Companies		6.8				6.8				9.7
Public Service Co Of Oklahoma [Member] | 2020 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		7.5				7.5
Public Service Co Of Oklahoma [Member] | 2021-2022 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Public Service Co Of Oklahoma [Member] | 2023-2024 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Public Service Co Of Oklahoma [Member] | 2024 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		287.2		352.2		569.7		662.0
Public Service Co Of Oklahoma [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		139.2		147.7		267.7		287.7
Public Service Co Of Oklahoma [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		77.3		101.3		153.4		182.1
Public Service Co Of Oklahoma [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		54.5		83.0		115.8		154.0
Public Service Co Of Oklahoma [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		16.2		20.2		32.8		38.2
Public Service Co Of Oklahoma [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		6.1		21.3		15.8		39.7
Public Service Co Of Oklahoma [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		2.2	[13]	5.8	[14]	4.1	[15]	14.4	[16]
Public Service Co Of Oklahoma [Member] | Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		3.9	[17]	15.5	[18]	11.7	[19]	25.3	[20]
Public Service Co Of Oklahoma [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		13.7	[21]	5.8	[22]	18.4	[23]	11.6	[24]
Public Service Co Of Oklahoma [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		307.0		379.3		603.9		713.3
Public Service Co Of Oklahoma [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		1.6		(31.2)		2.0		(32.4)
Public Service Co Of Oklahoma [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		1.6	[25]	(31.2)	[26]	2.0	[27]	(32.4)	[28]
Public Service Co Of Oklahoma [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		6.2		1.4		7.0		3.4
Total Revenues		0.0	[25]	0.0	[26]	0.0	[27]	0.0	[28]
Southwestern Electric Power Co [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		415.0		375.5		800.9		796.6
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		21.0				21.0
Revenue Textuals [Abstract]
Revenue from Related Parties		17.5		6.4		25.0		12.8
Affiliated Companies		41.7				41.7				34.5
Southwestern Electric Power Co [Member] | Short-term Contract with Customer [Member]
Revenue Textuals [Abstract]
Affiliated Companies		22.6				22.6				$ 17.6
Southwestern Electric Power Co [Member] | 2020 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		21.0				21.0
Southwestern Electric Power Co [Member] | 2021-2022 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Southwestern Electric Power Co [Member] | 2023-2024 [Member]
Revenue, Performance Obligation [Abstract]
Fixed Performance Obligations		0.0				0.0
Southwestern Electric Power Co [Member] | 2024 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		342.9		339.7		661.9		676.9
Southwestern Electric Power Co [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		147.7		140.7		279.3		280.8
Southwestern Electric Power Co [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		110.6		113.1		216.2		226.8
Southwestern Electric Power Co [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		82.3		83.7		162.1		164.9
Southwestern Electric Power Co [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		2.3		2.2		4.3		4.4
Southwestern Electric Power Co [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		63.7		68.6		123.2		150.0
Southwestern Electric Power Co [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		30.3	[13]	44.8	[14]	64.4	[15]	102.0	[16]
Southwestern Electric Power Co [Member] | Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		33.4	[17]	23.8	[18]	58.8	[19]	48.0	[20]
Southwestern Electric Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		9.7	[21]	5.3	[22]	15.5	[23]	13.1	[24]
Southwestern Electric Power Co [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		416.3		413.6		800.6		840.0
Southwestern Electric Power Co [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(1.3)		(38.1)		0.3		(43.4)
Southwestern Electric Power Co [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(1.3)	[25]	(38.1)	[26]	0.3	[27]	(43.4)	[28]
Southwestern Electric Power Co [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.9		0.3		1.7		0.7
Total Revenues		0.0	[25]	0.0	[26]	0.0	[27]	0.0	[28]
Consolidation Eliminations [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
Total Revenues		(278.6)		(311.3)		(633.4)		(643.5)
Revenue Textuals [Abstract]
Revenue from Related Parties		(278.6)		(311.3)		(633.4)		(643.5)
Consolidation Eliminations [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(0.2)		(3.3)		(0.4)		(1.5)
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		(0.2)		(3.3)		(0.4)		(1.5)
Consolidation Eliminations [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0				0.0		0.0
Consolidation Eliminations [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(228.6)		(166.4)		(521.6)		(457.7)
Consolidation Eliminations [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		7.2	[1]	0.0		(71.3)	[2]
Consolidation Eliminations [Member] | Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(201.8)	[3]	(173.6)	[4]	(464.8)	[5]	(386.4)	[6]
Consolidation Eliminations [Member] | Renewable Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(0.3)	[7]	0.0	[8]	(0.9)	[9]	0.0	[10]
Consolidation Eliminations [Member] | Retail, Trading and Marketing Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(26.5)	[11]	0.0	[8]	(55.9)	[12]	0.0	[10]
Consolidation Eliminations [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(31.4)	[7]	(35.3)	[8]	(72.0)	[9]	(71.4)	[10]
Consolidation Eliminations [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(260.2)		(205.0)		(594.0)		(530.6)
Consolidation Eliminations [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(18.4)		(106.3)		(39.4)		(112.9)
Consolidation Eliminations [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(7.6)	[7]	(36.9)	[8]	(3.1)	[9]	(43.5)	[10]
Consolidation Eliminations [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(10.8)	[7]	(69.4)	[8]	(36.3)	[9]	(69.4)	[10]
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
Vertically Integrated Utilities [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		2,092.0		2,123.8		4,318.7		4,527.1
Revenue Textuals [Abstract]
Revenue from Related Parties		29.7		7.4		63.4		38.4
Vertically Integrated Utilities [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		1,818.1		1,865.3		3,780.7		3,934.3
Vertically Integrated Utilities [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		820.7		755.0		1,735.8		1,737.4
Vertically Integrated Utilities [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		474.5		517.5		963.9		1,028.7
Vertically Integrated Utilities [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		486.0		549.2		1,004.2		1,081.3
Vertically Integrated Utilities [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		36.9		43.6		76.8		86.9
Vertically Integrated Utilities [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		232.7		270.0		453.0		568.2
Vertically Integrated Utilities [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		148.6		205.9	[1]	289.0		430.6	[2]
Vertically Integrated Utilities [Member] | Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		84.1	[3]	64.1	[4]	164.0	[5]	137.6	[6]
Vertically Integrated Utilities [Member] | Renewable Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[7]	0.0	[8]	0.0	[9]	0.0	[10]
Vertically Integrated Utilities [Member] | Retail, Trading and Marketing Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[11]	0.0	[8]	0.0	[12]	0.0	[10]
Vertically Integrated Utilities [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		46.4	[7]	42.0	[8]	90.0	[9]	81.5	[10]
Vertically Integrated Utilities [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		2,097.2		2,177.3		4,323.7		4,584.0
Vertically Integrated Utilities [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(5.2)		(53.5)		(5.0)		(56.9)
Vertically Integrated Utilities [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(5.2)	[7]	(53.5)	[8]	(5.0)	[9]	(56.9)	[10]
Vertically Integrated Utilities [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		0.0	[7]	0.0	[8]	0.0	[9]	0.0	[10]
Transmission And Distribution Utilities [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		1,034.5		1,045.7		2,141.4		2,267.7
Revenue Textuals [Abstract]
Revenue from Related Parties		25.1		44.1		56.8		86.3
Transmission And Distribution Utilities [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		859.8		843.1		1,767.6		1,875.1
Transmission And Distribution Utilities [Member] | Residential [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		494.5		435.0		1,015.8		1,021.1
Transmission And Distribution Utilities [Member] | Commercial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		256.3		287.6		533.2		598.5
Transmission And Distribution Utilities [Member] | Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		98.7		109.4		196.5		233.3
Transmission And Distribution Utilities [Member] | Other Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		10.3		11.1		22.1		22.2
Transmission And Distribution Utilities [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		108.4		113.5		222.5		213.1
Transmission And Distribution Utilities [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0	[1]	0.0		0.0	[2]
Transmission And Distribution Utilities [Member] | Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		108.4	[3]	113.5	[4]	222.5	[5]	213.1	[6]
Transmission And Distribution Utilities [Member] | Renewable Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[7]	0.0	[8]	0.0	[9]	0.0	[10]
Transmission And Distribution Utilities [Member] | Retail, Trading and Marketing Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[11]	0.0	[8]	0.0	[12]	0.0	[10]
Transmission And Distribution Utilities [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		33.1	[7]	38.7	[8]	69.5	[9]	84.7	[10]
Transmission And Distribution Utilities [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		1,001.3		995.3		2,059.6		2,172.9
Transmission And Distribution Utilities [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		33.2		50.4		81.8		94.8
Transmission And Distribution Utilities [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		20.6	[7]	11.4	[8]	39.9	[9]	16.4	[10]
Transmission And Distribution Utilities [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		12.6	[7]	39.0	[8]	41.9	[9]	78.4	[10]
AEP Transmission Holdco [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		249.7		278.9		559.9		535.3
AEP Transmission Holdco [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
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		310.2		289.8		620.0		544.9
AEP Transmission Holdco [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0	[1]	0.0		0.0	[2]
AEP Transmission Holdco [Member] | Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		310.2	[3]	289.8	[4]	620.0	[5]	544.9	[6]
Revenue Textuals [Abstract]
Revenue from Related Parties		240.0		201.0		479.0		399.0
AEP Transmission Holdco [Member] | Renewable Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[7]	0.0	[8]	0.0	[9]	0.0	[10]
AEP Transmission Holdco [Member] | Retail, Trading and Marketing Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[11]	0.0	[8]	0.0	[12]	0.0	[10]
AEP Transmission Holdco [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		11.4	[7]	5.0	[8]	15.1	[9]	8.1	[10]
AEP Transmission Holdco [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		321.6		294.8		635.1		553.0
AEP Transmission Holdco [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(71.9)		(15.9)		(75.2)		(17.7)
AEP Transmission Holdco [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(71.9)	[7]	(15.9)	[8]	(75.2)	[9]	(17.7)	[10]
AEP Transmission Holdco [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		0.0	[7]	0.0	[8]	0.0	[9]	0.0	[10]
Generation And Marketing [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		376.9		412.7		815.5		894.5
Revenue Textuals [Abstract]
Revenue from Related Parties		26.7		29.8		56.9		71.9
Generation And Marketing [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
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
Generation And Marketing [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		376.8		406.6		796.8		878.0
Generation And Marketing [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		31.5		299.7	[1]	75.6		408.5	[2]
Revenue Textuals [Abstract]
Revenue from Related Parties		27.0		34.0		62.0		71.0
Generation And Marketing [Member] | Wholesale Transmission [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0	[3]	0.0	[4]	0.0	[5]	0.0	[6]
Generation And Marketing [Member] | Renewable Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		17.7	[7]	11.1	[8]	34.9	[9]	18.8	[10]
Generation And Marketing [Member] | Retail, Trading and Marketing Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		327.6	[11]	95.8	[8]	686.3	[12]	450.7	[10]
Generation And Marketing [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.7	[7]	(12.6)	[8]	1.0	[9]	(10.3)	[10]
Generation And Marketing [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		377.5		394.0		797.8		867.7
Generation And Marketing [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(0.6)		18.7		17.7		26.8
Generation And Marketing [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		0.0	[7]	0.0	[8]	0.0	[9]	0.0	[10]
Generation And Marketing [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(0.6)	[7]	18.7	[8]	17.7	[9]	26.8	[10]
Other Segments [Member]
Disaggregation of Revenue [Abstract]
Total Revenues	[29]	19.5		23.8		39.4		49.3
Revenue Textuals [Abstract]
Revenue from Related Parties	[29]	16.6		20.9		38.7		42.6
Other Segments [Member] | Retail [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0		0.0		0.0
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
Other Segments [Member] | Wholesale and Competitive [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(0.6)		0.0		(6.6)		0.0
Other Segments [Member] | Wholesale Generation [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		0.0		0.0	[1]	0.0		0.0	[2]
Other Segments [Member] | Wholesale Transmission [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] | Renewable Generation [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] | Retail, Trading and Marketing Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		(0.6)	[11]	0.0	[8]	(6.6)	[12]	0.0	[10]
Other Segments [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		22.4	[7]	21.5	[8]	50.5	[9]	44.8	[10]
Other Segments [Member] | Affiliated and Nonaffiliated [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers		21.8		21.5		43.9		44.8
Other Segments [Member] | Alternative and Other [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		(2.3)		2.3		(4.5)		4.5
Other Segments [Member] | Alternative [Member]
Disaggregation of Revenue [Abstract]
Total Revenues		0.0	[7]	0.0	[8]	0.0	[9]	0.0	[10]
Other Segments [Member] | Other Revenues [Member]
Disaggregation of Revenue [Abstract]
Revenue from Contracts with Customers	[29]	2.9		2.9		0.7		6.7
Total Revenues		$ (2.3)	[7]	$ 2.3	[8]	$ (4.5)	[9]	$ 4.5	[10]

[1] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for Generation & Marketing was $34 million. The remaining affiliated amounts were immaterial.

[2] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for Generation & Marketing was $71 million. The remaining affiliated amounts were immaterial.

[3] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEP Transmission Holdco was $240 million. The remaining affiliated amounts were immaterial.

[4] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEP Transmission Holdco was $201 million. The remaining affiliated amounts were immaterial.

[5] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEP Transmission Holdco was $479 million. The remaining affiliated amounts were immaterial.

[6] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEP Transmission Holdco was $399 million. The remaining affiliated amounts were immaterial.

[7] Amounts include affiliated and nonaffiliated revenues.

[8] Amounts include affiliated and nonaffiliated revenues.

[9] Amounts include affiliated and nonaffiliated revenues.

[10] Amounts include affiliated and nonaffiliated revenues.

[11] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for Generation & Marketing was $27 million. The remaining affiliated amounts were immaterial.

[12] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for Generation & Marketing was $62 million. The remaining affiliated amounts were immaterial.

[13] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for APCo was $24 million primarily relating to the PPA with KGPCo. The remaining affiliated amounts were immaterial

[14] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for APCo was $30 million primarily relating to the PPA with KGPCo. The remaining affiliated amounts were immaterial.

[15] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for APCo was $57 million primarily relating to the PPA with KGPCo. The remaining affiliated amounts were immaterial.

[16] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for APCo was $64 million primarily relating to the PPA with KGPCo. The remaining affiliated amounts were immaterial.

[17] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEPTCo was $237 million. The remaining affiliated amounts were immaterial.

[18] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEPTCo was $198 million. The remaining affiliated amounts were immaterial.

[19] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEPTCo was $472 million. The remaining affiliated amounts were immaterial.

[20] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for AEPTCo was $393 million. The remaining affiliated amounts were immaterial.

[21] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for I&M was $18 million primarily relating to barging, urea transloading and other transportation services. The remaining affiliated amounts were immaterial.

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

[23] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for I&M was $34 million primarily relating to barging, urea transloading and other transportation services. The remaining affiliated amounts were immaterial.

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

[25] Amounts include affiliated and nonaffiliated revenues.

[26] Amounts include affiliated and nonaffiliated revenues.

[27] Amounts include affiliated and nonaffiliated revenues.

[28] Amounts include affiliated and nonaffiliated revenues.

[29] 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, interest expense and other nonallocated costs.