Rate Matters West Companies (Details) $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($) MW	Dec. 31, 2022 USD ($)
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	$ 4,607.3	$ 4,762.0
Regulatory Assets Pending Final Regulatory Approval [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	886.3	919.3
Public Service Co Of Oklahoma [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	477.2	653.7
Public Service Co Of Oklahoma [Member] | Regulatory Assets Pending Final Regulatory Approval [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	93.0	25.6
Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	1,116.9	1,042.4
Southwestern Electric Power Co [Member] | Regulatory Assets Pending Final Regulatory Approval [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	446.5	547.3
AEP Texas Inc. [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	307.7	298.3
AEP Texas Inc. [Member] | Regulatory Assets Pending Final Regulatory Approval [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	$ 61.5	67.0
ETT Interim Transmission Rates [Member]
Public Utilities, General Disclosures [Line Items]
Parent Ownership Interest In ETT	50.00%
AEP Share Of ETT Cumulative Revenues Subject To Review	$ 1,600.0
February 2021 Severe Storm Fuel Costs | Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	269.4	329.0
February 2021 Severe Storm Fuel Costs | Southwestern Electric Power Co [Member] | Arkansas
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	$ 59.4	74.9
Remaining Recovery Period	6 years
February 2021 Severe Storm Fuel Costs | Southwestern Electric Power Co [Member] | Louisiana Jurisdiction [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	$ 101.4	121.7
February 2021 Severe Storm Fuel Costs | Southwestern Electric Power Co [Member] | Texas
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	$ 108.6	$ 132.4
Approved Carrying Charge	1.65%
Remaining Recovery Period	5 years
2012 Texas Base Rate Case [Member] | Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
2013 Reversal Of Previously Recorded Regulatory Disallowances	$ 114.0
Estimated Reduced Annual Revenues	15.0
2012 Texas Base Rate Case [Member] | Southwestern Electric Power Co [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Turk AFUDC Disallowance	80.0
Estimated Turk AFUDC Refunds	0.0
2012 Texas Base Rate Case [Member] | Southwestern Electric Power Co [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Turk AFUDC Disallowance	90.0
Estimated Turk AFUDC Refunds	200.0
2016 Texas Base Rate Case [Member] | Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Requested Net Increase in Texas Annual Revenues	69.0
Approved Net Increase in Texas Annual Revenues	$ 50.0
Approved Return on Common Equity	9.60%
Approved Additional Vegetation Management Expenses	$ 2.0
Impairment Charge Total	19.0
Impairment Charge Welsh Plant, Unit 2	7.0
Impairment Charge Disallowed Plant Investments	12.0
Additional Revenues Recognized to be Surcharged to Customers	32.0
Additional Recognized Expenses Consisting Primarily of Depreciation and Vegetation Management	$ 7.0
Requested Return on Equity	10.00%
2020 Texas Base Rate Case [Member] | Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Approved Return on Common Equity	9.25%
Impairment Charge Total	$ 12.0
Requested Annual Increase	$ 105.0
Requested Return on Equity	10.35%
Requested Net Annual Increase	$ 90.0
Revised Requested Annual Increase	100.0
Revised Requested Net Annual Increase	85.0
Approved Annual Revenue Increase	39.0
Amount of Approved Increase Related to Vegetation Management	5.0
Amount of Approved Increase Related to Storm Catastrophe Reserve	$ 2.0
2020 Louisiana Base Rate Case | Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Requested Return on Equity	10.35%
Approved Return on Common Equity	9.50%
Requested Annual Increase	$ 134.0
Revised Requested Annual Increase	95.0
Approved Annual Revenue Increase	27.0
Authorized Annual Base Rate Increase	21.0
Approved Rider to Recover Dolet Hills and Pirkey Costs	14.0
Reduction in Fuel Costs	$ 8.0
2021 Louisiana Storm Cost Filing | Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Interim WACC	3.125%
Approved Deferred Storm Costs	$ 150.0
AEP Texas Interim Transmission and Distribution Rates [Member] | AEP Texas Inc. [Member]
Public Utilities, General Disclosures [Line Items]
AEP Texas Cumulative Revenues Subject to Review	$ 884.0
2022 Oklahoma Base Rate Case [Member] | Public Service Co Of Oklahoma [Member]
Public Utilities, General Disclosures [Line Items]
Requested Return on Equity	10.40%
Amount of Increase Related to Annual Depreciation Expense	$ 47.0
Requested Debt Capital Structure	45.40%
Requested Equity Capital Structure	54.60%
Requested Net Increase in Oklahoma Annual Revenues	$ 173.0
Amount of Increase Related to Annual Amortization Expense	$ 16.0
Wind Generation MWs | MW	154
OCC Staff and Intervenor Recommended Plant Investments	$ 9.0
Contested Joint Agreement Base Rate Annual Revenue Increase	$ 50.0
Contested Joint Agreement Return on Equity	9.50%
Contested Joint Agreement Debt Capital Structure	45.40%
Contested Joint Agreement Equity Capital Structure	54.60%
Contested Joint Agreement Distribution Investments Recovery	$ 6.0
Contested Joint Agreement Interim Annual Base Rate Cumulative Revenue Increase	80.0
2022 Oklahoma Base Rate Case [Member] | Public Service Co Of Oklahoma [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
OCC Staff and Intervenor Recommended Annual Revenue Change Range	$ 42.0
OCC Staff and Intervenor Recommended ROE Range	8.60%
2022 Oklahoma Base Rate Case [Member] | Public Service Co Of Oklahoma [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
OCC Staff and Intervenor Recommended Annual Revenue Change Range	$ 49.0
OCC Staff and Intervenor Recommended ROE Range	9.50%