Variable Interest Entities (Details) - USD ($) $ in Millions	Jun. 30, 2024		Mar. 31, 2024	Dec. 31, 2023		Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
ASSETS
Current Assets	$ 6,652.8			$ 6,082.1
Net Property, Plant and Equipment	78,860.4			76,693.4
Other Noncurrent Assets	14,109.4			13,908.5
Total Assets	99,622.6	[1]		96,684.0
LIABILITIES AND EQUITY
Current Liabilities	10,162.7			11,583.6
Noncurrent Liabilities	63,227.3			59,772.0
Equity	26,175.7		$ 25,843.7	25,285.9		$ 24,123.6	$ 23,967.8	$ 24,122.4
Total Liabilities and Equity	99,622.6			96,684.0
Southwestern Electric Power Co [Member]
ASSETS
Current Assets	605.6			541.3
Net Property, Plant and Equipment	8,797.9			8,558.4
Other Noncurrent Assets	1,488.5			1,457.9
Total Assets	10,892.0			10,557.6
LIABILITIES AND EQUITY
Current Liabilities	1,050.7			686.9
Noncurrent Liabilities	6,083.0			6,100.3
Equity	3,758.3		3,928.4	3,770.4		3,795.5	3,765.2	3,674.8
Total Liabilities and Equity	10,892.0			10,557.6
Indiana Michigan Power Co [Member]
ASSETS
Current Assets	527.2			528.0
Net Property, Plant and Equipment	7,731.3			7,629.0
Other Noncurrent Assets	5,147.2			4,651.0
Total Assets	13,405.7			12,808.0
LIABILITIES AND EQUITY
Current Liabilities	1,036.3			830.2
Noncurrent Liabilities	9,118.9			8,837.6
Equity	3,250.5		3,247.8	3,140.2		3,120.7	3,077.3	3,008.3
Total Liabilities and Equity	13,405.7			12,808.0
AEP Texas Inc. [Member]
ASSETS
Current Assets	832.5			520.1
Net Property, Plant and Equipment	13,374.8			12,774.0
Other Noncurrent Assets	741.1			696.6
Total Assets	14,948.4			13,990.7
LIABILITIES AND EQUITY
Current Liabilities	820.5			749.4
Noncurrent Liabilities	9,116.0			8,445.2
Equity	5,011.9		4,879.7	4,796.1		4,334.6	4,051.3	3,904.3
Total Liabilities and Equity	14,948.4			13,990.7
Appalachian Power Co [Member]
ASSETS
Current Assets	1,118.0			1,059.0
Net Property, Plant and Equipment	13,253.6			12,931.5
Other Noncurrent Assets	1,872.9			1,721.4
Total Assets	16,244.5			15,711.9
LIABILITIES AND EQUITY
Current Liabilities	1,674.0			1,685.9
Noncurrent Liabilities	8,990.5			8,749.3
Equity	5,580.0		$ 5,512.7	5,276.7		$ 5,133.1	$ 5,086.9	$ 4,975.4
Total Liabilities and Equity	16,244.5			15,711.9
Sabine Mining Co [Member] | Variable Interest Entities [Member] | Southwestern Electric Power Co [Member]
ASSETS
Current Assets	4.1			4.2
Net Property, Plant and Equipment	0.0			0.0
Other Noncurrent Assets	130.2			150.7
Total Assets	134.3			154.9
LIABILITIES AND EQUITY
Current Liabilities	21.6			19.9
Noncurrent Liabilities	112.4			134.8
Equity	0.3			0.2
Total Liabilities and Equity	134.3			154.9
DCC Fuel [Member] | Variable Interest Entities [Member] | Indiana Michigan Power Co [Member]
ASSETS
Current Assets	100.3			81.9
Net Property, Plant and Equipment	188.4			153.8
Other Noncurrent Assets	96.3			81.7
Total Assets	385.0			317.4
LIABILITIES AND EQUITY
Current Liabilities	100.1			81.7
Noncurrent Liabilities	284.9			235.7
Equity	0.0			0.0
Total Liabilities and Equity	385.0			317.4
AEP Texas Central Transition Funding Co [Member] | AEP Texas Inc. [Member] | Other Noncurrent Assets [Member]
LIABILITIES AND EQUITY
Unearned Revenue	4.0			8.0
AEP Texas Central Transition Funding Co [Member] | Variable Interest Entities [Member] | AEP Texas Inc. [Member]
ASSETS
Current Assets	25.2			25.5
Net Property, Plant and Equipment	0.0			0.0
Other Noncurrent Assets	39.1	[2]		71.4	[3]
Total Assets	64.3			96.9
LIABILITIES AND EQUITY
Current Liabilities	43.1			75.5
Noncurrent Liabilities	16.6			17.0
Equity	4.6			4.4
Total Liabilities and Equity	64.3			96.9
Restoration Funding [Member] | AEP Texas Inc. [Member] | Other Noncurrent Assets [Member]
LIABILITIES AND EQUITY
Unearned Revenue	6.0			6.0
Restoration Funding [Member] | Variable Interest Entities [Member] | AEP Texas Inc. [Member]
ASSETS
Current Assets	22.0			27.5
Net Property, Plant and Equipment	0.0			0.0
Other Noncurrent Assets	133.8	[4]		145.6	[5]
Total Assets	155.8			173.1
LIABILITIES AND EQUITY
Current Liabilities	30.5			36.8
Noncurrent Liabilities	124.0			135.1
Equity	1.3			1.2
Total Liabilities and Equity	155.8			173.1
Appalachian Consumer Rate Relief Funding [Member] | Appalachian Power Co [Member] | Other Noncurrent Assets [Member]
LIABILITIES AND EQUITY
Unearned Revenue	1.0			2.0
Appalachian Consumer Rate Relief Funding [Member] | Variable Interest Entities [Member] | Appalachian Power Co [Member]
ASSETS
Current Assets	13.9			13.3
Net Property, Plant and Equipment	0.0			0.0
Other Noncurrent Assets	124.0	[6]		138.2	[7]
Total Assets	137.9			151.5
LIABILITIES AND EQUITY
Current Liabilities	30.2			29.9
Noncurrent Liabilities	105.8			119.7
Equity	1.9			1.9
Total Liabilities and Equity	137.9			151.5
AEP Credit, Inc. [Member] | Variable Interest Entities [Member]
ASSETS
Current Assets	1,233.0			1,208.8
Net Property, Plant and Equipment	0.0			0.0
Other Noncurrent Assets	10.3			9.6
Total Assets	1,243.3			1,218.4
LIABILITIES AND EQUITY
Current Liabilities	1,178.8			1,155.0
Noncurrent Liabilities	1.0			0.9
Equity	63.5			62.5
Total Liabilities and Equity	1,243.3			1,218.4
Protected Cell Of Energy Insurance Services, Inc. [Member] | Variable Interest Entities [Member]
ASSETS
Current Assets	207.5			205.3
Net Property, Plant and Equipment	0.0			0.0
Other Noncurrent Assets	0.0			0.0
Total Assets	207.5			205.3
LIABILITIES AND EQUITY
Current Liabilities	43.3			49.2
Noncurrent Liabilities	91.9			91.7
Equity	72.3			64.4
Total Liabilities and Equity	207.5			205.3
Transource Energy [Member] | Variable Interest Entities [Member]
ASSETS
Current Assets	46.4			36.9
Net Property, Plant and Equipment	561.4			533.4
Other Noncurrent Assets	7.7			5.1
Total Assets	615.5			575.4
LIABILITIES AND EQUITY
Current Liabilities	44.6			45.3
Noncurrent Liabilities	273.1			241.5
Equity	297.8			288.6
Total Liabilities and Equity	$ 615.5			$ 575.4

[1] Amount includes Assets Held for Sale on the balance sheet. See “Planned Disposition of AEP OnSite Partners” section of Note 6 for additional information.

[2] Includes an intercompany item eliminated in consolidation of $4 million.

[3] Includes an intercompany item eliminated in consolidation of $8 million.

[4] Includes an intercompany item eliminated in consolidation of $6 million.

[5] Includes an intercompany item eliminated in consolidation of $6 million.

[6] Includes an intercompany item eliminated in consolidation of $1 million.

[7] Includes an intercompany item eliminated in consolidation of $2 million.