v3.25.2
RATE MATTERS - Regulatory Assets Pending Final Approval (Details) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2025
Dec. 31, 2024
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets $ 4,870.2 $ 5,129.2
Regulatory assets, current 547.4 445.9
AEP Texas    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 383.3 353.6
Requested annual base rate increase 43.0  
APCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 1,451.3 1,366.0
Regulatory assets, current 128.3 148.1
I&M    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 616.1 548.1
Regulatory assets, current 5.0 10.6
OPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 364.1 379.1
PSO    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 551.9 527.8
Regulatory assets, current 139.0 64.7
SWEPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 944.9 921.3
Regulatory assets, current 109.6 106.6
Total Regulatory Assets Pending Final Regulatory Approval    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 1,527.9 1,348.0
Total Regulatory Assets Pending Final Regulatory Approval | AEP Texas    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 127.3 77.1
Total Regulatory Assets Pending Final Regulatory Approval | APCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 658.4 535.5
Total Regulatory Assets Pending Final Regulatory Approval | I&M    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 108.8 115.0
Total Regulatory Assets Pending Final Regulatory Approval | OPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 0.7 0.5
Total Regulatory Assets Pending Final Regulatory Approval | PSO    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 61.5 30.3
Total Regulatory Assets Pending Final Regulatory Approval | SWEPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 540.5 491.4
Welsh Plant, Units 1 and 3 Accelerated Depreciation | Regulatory Assets Currently Earning a Return    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 192.7 168.6
Welsh Plant, Units 1 and 3 Accelerated Depreciation | Regulatory Assets Currently Earning a Return | SWEPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 192.7 168.6
Pirkey Plant Accelerated Depreciation | Regulatory Assets Currently Earning a Return    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 132.6 121.3
Pirkey Plant Accelerated Depreciation | Regulatory Assets Currently Earning a Return | SWEPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 132.6 121.3
Unrecovered Winter Storm Fuel Costs | Regulatory Assets Currently Earning a Return    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 55.9 70.7
Unrecovered Winter Storm Fuel Costs | Regulatory Assets Currently Earning a Return | SWEPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 55.9 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 53.8 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 310.5 300.8
Storm-Related Costs | Regulatory Assets Currently Not Earning a Return | AEP Texas    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 30.9 13.1
Storm-Related Costs | Regulatory Assets Currently Not Earning a Return | APCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 163.2 144.2
Storm-Related Costs | Regulatory Assets Currently Not Earning a Return | I&M    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 24.0 6.3
Storm-Related Costs | Regulatory Assets Currently Not Earning a Return | PSO    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 21.3 4.9
Storm-Related Costs | Regulatory Assets Currently Not Earning a Return | SWEPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 45.9 39.9
AEP Texas House Bill 5247 | Regulatory Assets Currently Earning a Return    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 25.0 0.0
AEP Texas House Bill 5247 | Regulatory Assets Currently Earning a Return | AEP Texas    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 25.0 0.0
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Earning a Return    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 26.5 20.7
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Earning a Return | AEP Texas    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 1.2 0.0
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Earning a Return | APCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 1.3 1.1
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Earning a Return | I&M    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 6.7 6.4
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Earning a Return | OPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 0.7 0.4
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Earning a Return | SWEPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 17.1 10.8
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Not Earning a Return    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 107.3 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 1.4 1.3
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Not Earning a Return | APCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 20.9 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 1.9 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 9.5 1.2
Other Regulatory Assets Pending Final Regulatory Approval | Regulatory Assets Currently Not Earning a Return | SWEPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 18.7 18.7
Plant Retirement Costs – Asset Retirement Obligation Costs | Regulatory Assets Currently Not Earning a Return    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 378.3 357.4
Plant Retirement Costs – Asset Retirement Obligation Costs | Regulatory Assets Currently Not Earning a Return | APCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 299.4 282.1
Plant Retirement Costs – Asset Retirement Obligation Costs | Regulatory Assets Currently Not Earning a Return | I&M    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 76.2 74.0
2024-2025 Virginia Biennial Under-Earnings | Regulatory Assets Currently Not Earning a Return    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 156.5 78.4
2024-2025 Virginia Biennial Under-Earnings | Regulatory Assets Currently Not Earning a Return | APCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 156.5 78.4
NOLC Costs | Regulatory Assets Currently Not Earning a Return    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 88.8 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 23.2 16.4
NOLC Costs | Regulatory Assets Currently Not Earning a Return | SWEPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 65.6 49.6
Deferred Pension and OPEB Costs | Regulatory Assets Currently Not Earning a Return | AEP Texas    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 21.7 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 17.1 17.8
Pension Settlement | Regulatory Assets Currently Not Earning a Return | PSO    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets 7.5 7.8
Dolet Hills Power Station Accelerated Depreciation | Regulatory Assets Currently Earning a Return | SWEPCo    
Regulatory Asset [Line Items]    
 Noncurrent Regulatory Assets $ 12.0 $ 11.8