Rate Matters West Companies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	$ 4,087.6	$ 4,142.3
AEP Share of Independence Energy Connection Capital Costs	82.0
Regulatory Assets Pending Final Regulatory Approval [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	912.9	1,048.6
Public Service Co Of Oklahoma [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	1,042.0	1,037.4
Public Service Co Of Oklahoma [Member] | Regulatory Assets Pending Final Regulatory Approval [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	20.5	14.2
Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	962.3	1,005.3
Southwestern Electric Power Co [Member] | Regulatory Assets Pending Final Regulatory Approval [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	723.0	880.6
AEP Texas Inc. [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	277.7	275.2
AEP Texas Inc. [Member] | Regulatory Assets Pending Final Regulatory Approval [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	$ 45.8	$ 41.2
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	$ 1,400.0
February 2021 Severe Storm Fuel Costs | Public Service Co Of Oklahoma [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	$ 681.0
Interim WACC	0.75%
Approved Carrying Charge	0.75%
February 2021 Severe Storm Fuel Costs | Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	$ 418.0
February 2021 Severe Storm Fuel Costs | Southwestern Electric Power Co [Member] | Arkansas
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	$ 96.0
Interim WACC	0.30%
Requested Weighted Average Cost of Capital	6.05%
Intervenor Recommended WACC	1.65%
February 2021 Severe Storm Fuel Costs | Southwestern Electric Power Co [Member] | Louisiana Jurisdiction [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	$ 141.0
Interim WACC	3.25%
February 2021 Severe Storm Fuel Costs | Southwestern Electric Power Co [Member] | Texas
Public Utilities, General Disclosures [Line Items]
Regulatory Assets, Noncurrent	$ 181.0
Approved Carrying Charge	1.65%
Requested Weighted Average Cost of Capital	7.18%
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	180.0
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
Requested Return on Equity	10.00%
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
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
Amount of Increase Related to Vegetation Management	5.0
Amount of Increase Related to Annual Depreciation Expense	10.0
Amount of Increase Related to Storm Catastrophe Reserve	2.0
Requested Recovery of Dolet Hills Power Station	45.0
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 Annual Increase	$ 134.0
Requested Return on Equity	10.35%
Amount of Increase Related to Annual Depreciation Expense	$ 32.0
Revised Requested Annual Increase	114.0
Staff Recommended Annual Rate Increase	$ 6.0
Staff Recommended Return on Common Equity	9.10%
Requested Annual Increase in Rebuttal	$ 95.0
2020 Louisiana Base Rate Case | Southwestern Electric Power Co [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Intervenor Recommended Return on Common Equity	9.35%
2020 Louisiana Base Rate Case | Southwestern Electric Power Co [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Intervenor Recommended Return on Common Equity	9.80%
2021 Arkansas Rate Case | Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Requested Annual Increase	$ 85.0
Requested Return on Equity	10.35%
Amount of Increase Related to Annual Depreciation Expense	$ 14.0
Staff Recommended Annual Rate Increase	$ 47.0
Staff Recommended Return on Common Equity	9.30%
Requested Annual Increase in Rebuttal	$ 81.0
Requested Debt Capital Structure	48.70%
Requested Equity Capital Structure	51.30%
Amount of Increase Related to North Central Wind Facilities	$ 41.0
Amount of Increase Related to SPP Expenses	$ 6.0
Staff Recommended Debt Capital Structure	55.50%
Staff Recommended Equity Capital Structure	44.50%
2021 Arkansas Rate Case | Southwestern Electric Power Co [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Intervenor Recommended Return on Common Equity	8.75%
2021 Arkansas Rate Case | Southwestern Electric Power Co [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Intervenor Recommended Return on Common Equity	9.25%
2021 Louisiana Storm Cost Filing | Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Requested Deferred Storm Costs	$ 145.0
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	$ 368.0