Business Segments (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2023		Mar. 31, 2022		Dec. 31, 2022
Reportable Segment Information
Interest Expense		$ 415.7		$ 313.4
Revenue from Contracts with Customers		4,690.9		4,592.6
Revenue from Related Parties		0.0		0.0
Revenues		4,690.9		4,592.6
Net Income (Loss)		400.4		718.1
Income Tax (Expense) Benefit		10.4		52.8
Balance Sheet Information
Total Property, Plant and Equipment		96,708.1				$ 97,021.4
Accumulated Depreciation and Amortization		23,361.1				23,682.3
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		73,347.0				73,339.1
Total Assets		94,517.9	[1]			93,403.3
Long-term Debt Due Within One Year		2,905.1				2,486.4
Long-term Debt		36,239.1				34,314.6
Total Long-term Debt Outstanding		39,144.2				36,801.0
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reportable Segment Information
Interest Expense	[2]	0.7		1.1
Income Tax (Expense) Benefit		9.1		(10.5)
Interest Rate [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Reportable Segment Information
Interest Expense	[2]	0.7		1.1
Income Tax (Expense) Benefit		0.1		0.2
Vertically Integrated Utilities [Member]
Reportable Segment Information
Revenue from Contracts with Customers		2,816.3		2,646.8
Transmission and Distribution Utilities Revenues [Member]
Reportable Segment Information
Revenue from Contracts with Customers		1,455.3		1,242.2
Generation and Marketing Revenues [Member]
Reportable Segment Information
Revenue from Contracts with Customers		326.9		609.5
Generation and Marketing Revenues [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reportable Segment Information
Revenue from Contracts with Customers	[2]			(0.1)
Generation and Marketing Revenues [Member] | Interest Rate [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Reportable Segment Information
Revenue from Contracts with Customers	[2]			0.0
Other Revenues [Member]
Reportable Segment Information
Revenue from Contracts with Customers		92.4		94.1
Revenues		(129.9)	[3]	165.4	[4],[5]
AEP Transmission Co [Member]
Reportable Segment Information
Interest Expense		45.2		37.7
Interest Income		1.5		0.1
Revenues from Related Parties, Net of Provisions for Refund		352.6		324.7
Revenue from Related Parties		357.4		325.0
Revenues		441.6		400.4
Net Income (Loss)		162.7		155.4
Income Tax (Expense) Benefit		47.7		45.5
Balance Sheet Information
Total Property, Plant and Equipment		14,803.2				14,366.9
Accumulated Depreciation and Amortization		1,091.2				1,027.0
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		13,712.0				13,339.9
Total Assets		14,454.7				13,814.2
Long-term Debt Due Within One Year		60.0				60.0
Long-term Debt		5,412.1				4,722.8
Total Long-term Debt Outstanding		5,472.1				4,782.8
AEP Transmission Co [Member] | Other Revenues [Member]
Reportable Segment Information
Revenues		0.0	[6]	0.0	[7]
AEP Transmission Co [Member] | Transmission [Member]
Reportable Segment Information
Revenue from Contract with Customers, Net of Provisions for Refund, Including Assessed Tax		89.0		75.7
Revenue from Contracts with Customers		90.0		87.0
Reconciling Adjustments [Member]
Reportable Segment Information
Revenue from Contracts with Customers		0.0		0.0
Revenue from Related Parties		(443.7)		(392.2)
Revenues		(443.7)		(392.2)
Net Income (Loss)		0.0		0.0
Balance Sheet Information
Total Assets	[8]	(5,583.3)	[1]			(5,783.0)
Reconciling Adjustments [Member] | Other Revenues [Member]
Reportable Segment Information
Revenues		(0.9)	[3]	(2.9)	[4],[5]
Reconciling Adjustments [Member] | AEP Transmission Co [Member]
Reportable Segment Information
Revenue from Contracts with Customers		0.0		0.0
Revenue from Related Parties		0.0		0.0
Revenues		0.0		0.0
Net Income (Loss)		0.0		0.0
Balance Sheet Information
Total Assets	[9]	(5,620.5)				(4,878.8)
Vertically Integrated Utilities [Member]
Reportable Segment Information
Revenue from Related Parties		41.5		40.6
Revenues		2,857.8		2,687.4
Net Income (Loss)		262.2		299.2
Balance Sheet Information
Total Assets		50,164.1	[1]			49,761.8
Vertically Integrated Utilities [Member] | Vertically Integrated Utilities [Member]
Reportable Segment Information
Revenue from Contracts with Customers		2,816.3		2,646.8
Vertically Integrated Utilities [Member] | Other Revenues [Member]
Reportable Segment Information
Revenues		(0.1)	[3]	0.0	[4],[5]
Transmission And Distribution Utilities [Member]
Reportable Segment Information
Revenue from Related Parties		8.9		4.6
Revenues		1,464.2		1,246.8
Net Income (Loss)		125.7		152.8
Balance Sheet Information
Total Assets		23,437.0	[1]			22,920.2
Transmission And Distribution Utilities [Member] | Transmission and Distribution Utilities Revenues [Member]
Reportable Segment Information
Revenue from Contracts with Customers		1,455.3		1,242.2
Transmission And Distribution Utilities [Member] | Other Revenues [Member]
Reportable Segment Information
Revenues		11.1	[3]	6.3	[4],[5]
AEP Transmission Holdco [Member]
Reportable Segment Information
Revenue from Related Parties		365.4		328.0
Revenues		455.5		411.4
Net Income (Loss)		182.4		173.7
Balance Sheet Information
Total Assets		15,883.1	[1]			15,215.8
AEP Transmission Holdco [Member] | Transmission [Member]
Reportable Segment Information
Revenue from Contracts with Customers		90.1		83.4
Generation And Marketing [Member]
Reportable Segment Information
Revenue from Related Parties		0.1		9.8
Revenues		327.0		619.3
Net Income (Loss)		(156.4)		116.0
Balance Sheet Information
Total Assets		4,159.8	[1]			4,520.1
Generation And Marketing [Member] | Generation and Marketing Revenues [Member]
Reportable Segment Information
Revenue from Contracts with Customers		326.9		609.5
Generation And Marketing [Member] | Other Revenues [Member]
Reportable Segment Information
Revenues		(141.0)	[3],[10]	159.2	[4],[5]
All Other [Member]
Reportable Segment Information
Revenue from Related Parties	[11]	27.8		9.2
Revenues	[11]	30.1		19.9
Net Income (Loss)	[11]	(13.5)		(23.6)
Balance Sheet Information
Total Assets	[11],[12]	6,457.2	[1]			6,768.4
All Other [Member] | Other Revenues [Member]
Reportable Segment Information
Revenue from Contracts with Customers	[11]	2.3		10.7
Revenues		1.0	[3]	2.8	[4],[5]
State Transcos [Member] | AEP Transmission Co [Member]
Reportable Segment Information
Revenue from Related Parties		352.6		324.7
Revenues		441.6		400.4
Net Income (Loss)		161.6		155.4
Balance Sheet Information
Total Assets		14,493.6				13,875.6
State Transcos [Member] | AEP Transmission Co [Member] | Transmission [Member]
Reportable Segment Information
Revenue from Contracts with Customers		89.0		75.7
AEPTCo Parent [Member] | AEP Transmission Co [Member]
Reportable Segment Information
Revenue from Contracts with Customers		0.0		0.0
Revenue from Related Parties		0.0		0.0
Revenues		0.0		0.0
Net Income (Loss)	[13]	1.1		$ 0.0
Balance Sheet Information
Total Assets	[14]	$ 5,581.6				$ 4,817.4

[1] Amount includes Assets Held for Sale on the balance sheet. See “Planned Disposition of the Competitive Contracted Renewables Portfolio” section of Note 6 for additional information.

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

[3] Amounts include affiliated and nonaffiliated revenues.

[4] Amounts include affiliated and nonaffiliated revenues

[5] Generation & Marketing includes economic hedge activity.

[6] Amounts include affiliated and nonaffiliated revenues.

[7] Amounts include affiliated and nonaffiliated revenues.

[8] Reconciling Adjustments for Total Assets primarily include elimination of intercompany advances to affiliates and intercompany accounts receivable.

[9] Primarily relates to the elimination of Notes Receivable from the State Transcos.

[10] Generation & Marketing includes economic hedge activity.

[11] 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.

[12] Includes elimination of AEP Parent’s investments in wholly-owned subsidiary companies.

[13] Includes the elimination of AEPTCo Parent’s equity earnings in the State Transcos.

[14] Primarily relates to Notes Receivable from the State Transcos.