VARIABLE INTEREST ENTITIES (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2023
ASSETS
Current Assets	$ 5,936.9	$ 5,788.8
Net Property, Plant and Equipment	83,562.7	82,415.6
Other Noncurrent Assets	14,895.0	14,873.6
TOTAL ASSETS	104,394.6	103,078.0
LIABILITIES AND EQUITY
Current Liabilities	14,242.3	13,009.3
Noncurrent Liabilities	62,741.6	63,044.8
Equity	27,364.0	26,986.1	$ 25,843.7	$ 25,285.9
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	104,394.6	103,078.0
SWEPCo
ASSETS
Current Assets	468.0	438.0
Net Property, Plant and Equipment	9,540.5	9,446.1
Other Noncurrent Assets	1,684.2	1,610.9
TOTAL ASSETS	11,692.7	11,495.0
LIABILITIES AND EQUITY
Current Liabilities	1,650.2	1,031.6
Noncurrent Liabilities	6,089.1	6,558.4
Equity	3,953.4	3,905.0	$ 3,928.4	$ 3,770.4
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	11,692.7	11,495.0
I&M
ASSETS
Current Assets	509.9	543.6
Net Property, Plant and Equipment	7,710.8	7,679.3
Other Noncurrent Assets	5,240.1	5,312.6
TOTAL ASSETS	13,460.8	13,535.5
LIABILITIES AND EQUITY
Current Liabilities	1,049.6	1,071.2
Noncurrent Liabilities	9,007.1	9,067.8
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	13,460.8	13,535.5
AEP Texas
ASSETS
Current Assets	484.5	500.4
Net Property, Plant and Equipment	14,341.6	14,043.5
Other Noncurrent Assets	737.6	655.7
TOTAL ASSETS	15,563.7	15,199.6
LIABILITIES AND EQUITY
Current Liabilities	1,656.6	1,407.1
Noncurrent Liabilities	8,921.1	8,907.9
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	15,563.7	15,199.6
APCo
ASSETS
Current Assets	1,002.7	1,094.9
Net Property, Plant and Equipment	13,726.8	13,612.5
Other Noncurrent Assets	2,045.0	1,958.5
TOTAL ASSETS	16,774.5	16,665.9
LIABILITIES AND EQUITY
Current Liabilities	1,969.7	2,025.5
Noncurrent Liabilities	8,942.5	8,892.4
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	16,774.5	16,665.9
Variable Interest Entity, Primary Beneficiary | AEP Credit
ASSETS
Current Assets	1,213.1	1,118.3
Net Property, Plant and Equipment	0.0	0.0
Other Noncurrent Assets	10.8	10.5
TOTAL ASSETS	1,223.9	1,128.8
LIABILITIES AND EQUITY
Current Liabilities	1,159.2	1,068.8
Noncurrent Liabilities	1.0	1.0
Equity	63.7	59.0
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	1,223.9	1,128.8
Variable Interest Entity, Primary Beneficiary | Protected Cell of EIS
ASSETS
Current Assets	227.8	218.5
Net Property, Plant and Equipment	0.0	0.0
Other Noncurrent Assets	1.0	0.0
TOTAL ASSETS	228.8	218.5
LIABILITIES AND EQUITY
Current Liabilities	58.5	54.7
Noncurrent Liabilities	111.5	96.0
Equity	58.8	67.8
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	228.8	218.5
Variable Interest Entity, Primary Beneficiary | Transource Energy
ASSETS
Current Assets	48.6	40.2
Net Property, Plant and Equipment	610.8	598.3
Other Noncurrent Assets	10.3	3.5
TOTAL ASSETS	669.7	642.0
LIABILITIES AND EQUITY
Current Liabilities	37.3	57.2
Noncurrent Liabilities	314.4	274.3
Equity	318.0	310.5
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	669.7	642.0
Variable Interest Entity, Primary Beneficiary | SWEPCo | Sabine
ASSETS
Current Assets	2.7	6.0
Net Property, Plant and Equipment	0.0	0.0
Other Noncurrent Assets	108.7	110.8
TOTAL ASSETS	111.4	116.8
LIABILITIES AND EQUITY
Current Liabilities	21.1	20.1
Noncurrent Liabilities	90.0	96.3
Equity	0.3	0.4
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	111.4	116.8
Variable Interest Entity, Primary Beneficiary | SWEPCo | SWEPCo Storm Recovery Funding
ASSETS
Current Assets	11.7
Net Property, Plant and Equipment	0.0
Other Noncurrent Assets	327.4
TOTAL ASSETS	339.1
LIABILITIES AND EQUITY
Current Liabilities	25.7
Noncurrent Liabilities	311.7
Equity	1.7
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	339.1
Variable Interest Entity, Primary Beneficiary | I&M | DCC Fuel
ASSETS
Current Assets	64.6	79.3
Net Property, Plant and Equipment	106.2	132.3
Other Noncurrent Assets	51.9	63.6
TOTAL ASSETS	222.7	275.2
LIABILITIES AND EQUITY
Current Liabilities	64.5	79.2
Noncurrent Liabilities	158.2	196.0
Equity	0.0	0.0
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	222.7	275.2
Variable Interest Entity, Primary Beneficiary | AEP Texas | AEP Texas Restoration Funding
ASSETS
Current Assets	12.5	14.2
Net Property, Plant and Equipment	0.0	0.0
Other Noncurrent Assets	116.7	109.6
TOTAL ASSETS	129.2	123.8
LIABILITIES AND EQUITY
Current Liabilities	30.2	30.5
Noncurrent Liabilities	97.7	91.4
Equity	1.3	1.9
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	129.2	123.8
Variable Interest Entity, Primary Beneficiary | AEP Texas | AEP Texas Restoration Funding
ASSETS
Current Assets		21.3
Net Property, Plant and Equipment		0.0
Other Noncurrent Assets		121.9
TOTAL ASSETS		143.2
LIABILITIES AND EQUITY
Current Liabilities		30.7
Noncurrent Liabilities		111.2
Equity		1.3
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY		143.2
Variable Interest Entity, Primary Beneficiary | AEP Texas | Long-term Risk Management Assets | AEP Texas Restoration Funding
LIABILITIES AND EQUITY
Intercompany item eliminated in consolidation	1.0	1.0
Variable Interest Entity, Primary Beneficiary | AEP Texas | Long-term Risk Management Assets | AEP Texas Restoration Funding
LIABILITIES AND EQUITY
Intercompany item eliminated in consolidation	5.0	5.0
Variable Interest Entity, Primary Beneficiary | APCo | APCo Appalachian Consumer Rate Relief Funding
ASSETS
Current Assets	7.9	3.4
Net Property, Plant and Equipment	0.0	0.0
Other Noncurrent Assets	100.8	331.4
TOTAL ASSETS	108.7	334.8
LIABILITIES AND EQUITY
Current Liabilities	29.8	24.4
Noncurrent Liabilities	77.0	308.7
Equity	1.9	1.7
TOTAL LIABILITIES, MEZZANINE EQUITY AND TOTAL EQUITY	$ 108.7	$ 334.8