RATE MATTERS - Regulatory Assets Pending Final Approval (Details) - USD ($) $ in Millions	1 Months Ended
	Feb. 28, 2025	Jan. 31, 2025	Mar. 31, 2025	Dec. 31, 2024
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			$ 5,133.6	$ 5,129.2
Regulatory assets, current			537.4	445.9
AEP Texas
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			343.4	353.6
APCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			1,436.6	1,366.0
Regulatory assets, current			135.4	148.1
I&M
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			550.0	548.1
Regulatory assets, current			7.0	10.6
OPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			318.9	379.1
PSO
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			529.8	527.8
Regulatory assets, current			141.0	64.7
SWEPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			919.4	921.3
Regulatory assets, current			111.4	106.6
Total Regulatory Assets Pending Final Regulatory Approval
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			1,459.6	1,348.0
Total Regulatory Assets Pending Final Regulatory Approval | AEP Texas
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			85.3	77.1
Total Regulatory Assets Pending Final Regulatory Approval | APCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			627.2	535.5
Total Regulatory Assets Pending Final Regulatory Approval | I&M
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			89.7	115.0
Total Regulatory Assets Pending Final Regulatory Approval | OPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			0.6	0.5
Total Regulatory Assets Pending Final Regulatory Approval | PSO
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			36.4	30.3
Total Regulatory Assets Pending Final Regulatory Approval | SWEPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			511.3	491.4
Welsh Plant, Units 1 and 3 Accelerated Depreciation | Regulatory Assets Currently Earning a Return
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			180.5	168.6
Welsh Plant, Units 1 and 3 Accelerated Depreciation | Regulatory Assets Currently Earning a Return | SWEPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			180.5	168.6
Pirkey Plant Accelerated Depreciation | Regulatory Assets Currently Earning a Return
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			121.4	121.3
Pirkey Plant Accelerated Depreciation | Regulatory Assets Currently Earning a Return | SWEPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			121.4	121.3
Unrecovered Winter Storm Fuel Costs | Regulatory Assets Currently Earning a Return
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			63.2	70.7
Unrecovered Winter Storm Fuel Costs | Regulatory Assets Currently Earning a Return | SWEPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			63.2	70.7
Regulatory assets, current			37.0	37.0
Storm-Related Costs | Regulatory Assets Currently Earning a Return
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			53.5	51.0
Storm-Related Costs | Regulatory Assets Currently Earning a Return | AEP Texas
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			41.3	41.3
Storm-Related Costs | Regulatory Assets Currently Not Earning a Return
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			339.6	300.8
Regulatory asset, recovery of fuel costs, deferred	$ 21.0	$ 62.0
Storm-Related Costs | Regulatory Assets Currently Not Earning a Return | AEP Texas
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			18.0	13.1
Storm-Related Costs | Regulatory Assets Currently Not Earning a Return | APCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			161.1	144.2
Storm-Related Costs | Regulatory Assets Currently Not Earning a Return | I&M
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			6.4	6.3
Storm-Related Costs | Regulatory Assets Currently Not Earning a Return | PSO
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			7.6	4.9
Storm-Related Costs | Regulatory Assets Currently Not Earning a Return | SWEPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			44.7	39.9
Plant Retirement Costs – Asset Retirement Obligation Costs | Regulatory Assets Currently Not Earning a Return
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			367.0	357.4
Plant Retirement Costs – Asset Retirement Obligation Costs | Regulatory Assets Currently Not Earning a Return | APCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			290.0	282.1
Plant Retirement Costs – Asset Retirement Obligation Costs | Regulatory Assets Currently Not Earning a Return | I&M
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			75.1	74.0
2024-2025 Virginia Biennial Under-Earnings | Regulatory Assets Currently Not Earning a Return
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			136.8	78.4
2024-2025 Virginia Biennial Under-Earnings | Regulatory Assets Currently Not Earning a Return | APCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			136.8	78.4
NOLC Costs | Regulatory Assets Currently Not Earning a Return
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			72.0	92.8
NOLC Costs | Regulatory Assets Currently Not Earning a Return | I&M
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			0.0	26.7
NOLC Costs | Regulatory Assets Currently Not Earning a Return | PSO
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			17.7	16.4
NOLC Costs | Regulatory Assets Currently Not Earning a Return | SWEPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			54.2	49.6
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Earning a Return
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			25.1	20.7
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Earning a Return | APCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			1.2	1.1
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Earning a Return | I&M
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			6.6	6.4
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Earning a Return | OPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			0.6	0.4
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Earning a Return | SWEPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			17.2	10.8
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Not Earning a Return
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			100.5	86.3
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Not Earning a Return | AEP Texas
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			1.3	1.3
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Not Earning a Return | APCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			20.6	11.9
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Not Earning a Return | I&M
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			1.6	1.6
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Not Earning a Return | OPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			0.0	0.1
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Not Earning a Return | PSO
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			11.1	9.0
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Not Earning a Return | SWEPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			18.3	18.7
Deferred Pension and OPEB Costs | Regulatory Assets Currently Not Earning a Return | AEP Texas
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			18.9	15.6
Line Inspection Costs | Regulatory Assets Currently Not Earning a Return | AEP Texas
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			5.8	5.8
Pension Settlement | Regulatory Assets Currently Not Earning a Return | APCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			17.5	17.8
Dolet Hills Power Station Accelerated Depreciation | Regulatory Assets Currently Earning a Return | SWEPCo
Regulatory Asset [Line Items]
Noncurrent Regulatory Assets			$ 11.8	$ 11.8