BUSINESS SEGMENTS - Schedule of AEPTCo's Reportable Segment Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Total Revenues	$ 19,721.3	$ 18,982.3	$ 19,639.5
Other Operation and Maintenance	4,452.7	4,086.8	4,127.5
Depreciation and Amortization	3,289.9	3,090.4	3,202.8
Taxes Other Than Income Taxes	1,596.3	1,492.3	1,469.8
Allowance for equity funds used during construction	211.0	174.9	133.7
Interest Expense	1,862.8	1,806.9	1,396.1
Income Tax Expense (Benefit)	(39.2)	54.6	5.4
Gross Property Additions	8,030.2	7,533.5	7,879.0
Total Assets	103,078.0	96,684.0
Operating Segments
Segment Reporting Information [Line Items]
Total Revenues	21,500.5	20,523.5	21,133.4
Other Operation and Maintenance	5,986.8	5,433.4	5,435.8
Depreciation and Amortization	3,310.7	3,106.4	3,201.9
Taxes Other Than Income Taxes	1,576.4	1,477.2	1,453.5
Allowance for equity funds used during construction	211.0	174.9	133.7
Interest Expense	1,368.7	1,406.7	1,200.0
Income Tax Expense (Benefit)	112.9	138.1	133.6
Gross Property Additions	7,594.7	7,495.5	7,881.9
Total Assets	101,506.6	95,814.6
Operating Segments | Nonrelated Party
Segment Reporting Information [Line Items]
Total Revenues	19,663.3	18,921.6	19,588.8
Corporate and Other
Segment Reporting Information [Line Items]
Total Revenues	183.1	168.0	109.9
Other Operation and Maintenance	136.3	103.1	130.0
Depreciation and Amortization	(20.8)	(16.0)	0.9
Taxes Other Than Income Taxes	0.4	0.2	0.2
Allowance for equity funds used during construction	0.0	0.0	0.0
Interest Expense	612.5	594.7	308.9
Income Tax Expense (Benefit)	(152.1)	(83.5)	(128.2)
Gross Property Additions	466.6	36.6	25.9
Total Assets	5,550.8	5,194.0
Corporate and Other | Nonrelated Party
Segment Reporting Information [Line Items]
Total Revenues	58.0	60.7	50.7
Reconciling Adjustments
Segment Reporting Information [Line Items]
Total Revenues	(1,962.3)	(1,709.2)	(1,603.8)
Other Operation and Maintenance	(1,670.4)	(1,449.7)	(1,438.3)
Depreciation and Amortization	0.0	0.0	0.0
Taxes Other Than Income Taxes	19.5	14.9	16.1
Allowance for equity funds used during construction	0.0	0.0	0.0
Interest Expense	(118.4)	(194.5)	(112.8)
Income Tax Expense (Benefit)	0.0	0.0	0.0
Gross Property Additions	(31.1)	1.4	(28.8)
Total Assets	(3,979.4)	(4,324.6)
Reconciling Adjustments | Nonrelated Party
Segment Reporting Information [Line Items]
Total Revenues	0.0	0.0	0.0
AEP TRANSMISSION COMPANY, LLC
Segment Reporting Information [Line Items]
Total Revenues	1,890.9	1,672.0	1,624.5
Other Revenues			(0.2)
Other Operation and Maintenance	158.3	129.4	153.5
Depreciation and Amortization	430.9	393.8	346.2
Taxes Other Than Income Taxes	308.7	283.2	271.1
Interest Income	10.5	7.0	1.6
Allowance for equity funds used during construction	89.4	83.2	70.7
Interest Expense	214.2	194.5	162.7
Income Tax Expense (Benefit)	190.3	147.1	169.1
NET INCOME	688.4	614.2	594.2
Gross Property Additions	1,481.8	1,503.1	1,468.3
Total Assets	16,370.3	15,072.5
AEP TRANSMISSION COMPANY, LLC | Nonrelated Party
Segment Reporting Information [Line Items]
Total Revenues	378.6	354.2	340.9
AEP TRANSMISSION COMPANY, LLC | Affiliated Entity
Segment Reporting Information [Line Items]
Total Revenues	1,512.3	1,317.8	1,283.8
AEP TRANSMISSION COMPANY, LLC | Operating Segments
Segment Reporting Information [Line Items]
Total Revenues	1,890.9	1,672.0	1,624.5
Other Operation and Maintenance	156.6	129.2	152.8
Taxes Other Than Income Taxes	308.7	283.2	271.1
AEP TRANSMISSION COMPANY, LLC | Corporate and Other
Segment Reporting Information [Line Items]
Total Revenues	0.0	0.0	0.0
Other Revenues			0.0
Other Operation and Maintenance	1.7	0.2	0.7
Depreciation and Amortization	0.0	0.0	0.0
Taxes Other Than Income Taxes	0.0	0.0	0.0
Interest Income	241.1	218.0	177.8
Allowance for equity funds used during construction	0.0	0.0	0.0
Interest Expense	238.7	215.1	177.1
Income Tax Expense (Benefit)	0.1	1.4	0.0
NET INCOME	0.6	1.3	0.0
Gross Property Additions	0.0	0.0	0.0
Total Assets	8,670.4	5,486.6
AEP TRANSMISSION COMPANY, LLC | Corporate and Other | Nonrelated Party
Segment Reporting Information [Line Items]
Total Revenues	0.0	0.0	0.0
AEP TRANSMISSION COMPANY, LLC | Corporate and Other | Affiliated Entity
Segment Reporting Information [Line Items]
Total Revenues	0.0	0.0	0.0
AEP TRANSMISSION COMPANY, LLC | Reconciling Adjustments
Segment Reporting Information [Line Items]
Total Revenues	0.0	0.0	0.0
Other Revenues			0.0
Other Operation and Maintenance	0.0	0.0	0.0
Depreciation and Amortization	0.0	0.0	0.0
Taxes Other Than Income Taxes	0.0	0.0	0.0
Interest Income	(238.5)	(214.8)	(176.9)
Allowance for equity funds used during construction	0.0	0.0	0.0
Interest Expense	(238.5)	(214.8)	(176.9)
Income Tax Expense (Benefit)	0.0	0.0	0.0
NET INCOME	0.0	0.0	0.0
Gross Property Additions	0.0	0.0	0.0
Total Assets	(9,187.8)	(5,534.7)
AEP TRANSMISSION COMPANY, LLC | Reconciling Adjustments | Nonrelated Party
Segment Reporting Information [Line Items]
Total Revenues	0.0	0.0	0.0
AEP TRANSMISSION COMPANY, LLC | Reconciling Adjustments | Affiliated Entity
Segment Reporting Information [Line Items]
Total Revenues	0.0	0.0	0.0
State Transcos | AEP TRANSMISSION COMPANY, LLC | Operating Segments
Segment Reporting Information [Line Items]
Other Revenues			(0.2)
Depreciation and Amortization	430.9	393.8	346.2
Interest Income	7.9	3.8	0.7
Allowance for equity funds used during construction	89.4	83.2	70.7
Interest Expense	214.0	194.2	162.5
Income Tax Expense (Benefit)	190.2	145.7	169.1
NET INCOME	687.8	612.9	594.2
Gross Property Additions	1,481.8	1,503.1	1,468.3
Total Assets	16,887.7	15,120.6
State Transcos | AEP TRANSMISSION COMPANY, LLC | Operating Segments | Nonrelated Party
Segment Reporting Information [Line Items]
Total Revenues	378.6	354.2	340.9
State Transcos | AEP TRANSMISSION COMPANY, LLC | Operating Segments | Affiliated Entity
Segment Reporting Information [Line Items]
Total Revenues	$ 1,512.3	$ 1,317.8	$ 1,283.8