Stock-Based Compensation (Details) - USD ($)		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock Based Compensation (Textuals)
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant		10,000,000
Number of Shares Remaining Available for Issuance Under the AEP Long-Term Incentive Plan		6,712,148
Reduction in Aggregate Common Shares Authorized Per Share Issued Pursuant to Stock Options or Stock Appreciation Rights		0.286
Performance Units and AEP Career Shares Reinvested Dividends Portion For [Member]
Performance Units
Awarded Units	[1]	73,400	66,400	80,200
Vesting Period	[2]	(b)	(b)	(b)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology
Weighted Average Grant Date Fair Value		$ 84.87	$ 88.73	$ 70.58
Stock Based Compensation [Member]
Compensation Cost and Actual Tax Benefit Realized for the Tax Deductions from Compensation Cost for Share-based Payment Arrangements
Compensation Cost for Share-based Payment Arrangements	[3]	$ 53,800,000	$ 57,900,000	$ 53,200,000
Actual Tax Benefit Realized		7,200,000	8,400,000	7,700,000
Total Compensation Cost Capitalized		20,400,000	$ 20,000,000.0	$ 19,700,000
Stock Based Compensation (Textuals)
Total Unrecognized Compensation Cost Related to Unvested Share-based Compensation Arrangements Granted		$ 78,000,000
Weighted-average Period of Unrecognized Compensation Costs (in years)		1.39 years
Stock Unit Accumulation Plan for Non Employee Directors [Member]
Stock Based Compensation (Textuals)
Number of Years After Termination of Board Service Participant Can Elect to Have Stock Units Paid in Cash		10 years
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology
Weighted Average Grant Date Fair Value		$ 83.80	$ 89.13	$ 70.41
Awarded Units		12,100	10,000.0	11,400
Restricted Stock Units (RSUs) [Member]
Total Fair Value and Total Intrinsic Value of Restricted Shares and Restricted Stock Units Vested
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value		$ 22,900,000	$ 16,300,000	$ 16,600,000
Intrinsic Value of Restricted Shares and Restricted Stock Units Vested	[4]	$ 25,200,000	$ 21,600,000	$ 19,200,000
Status of Nonvested Restricted Shares and Restricted Stock Units
Nonvested, Shares/Units, Beginning Balance		516,900
Nonvested, Weighted Average Grant Date Fair Value, Beginning of Period		$ 75.55
Shares/Units, Vested		(307,600)
Weighted Average Grant Date Fair Value, Vested		$ 74.58
Shares/Units, Forfeited		(30,000.0)
Weighted Average Grant Date Fair Value, Shares/Units, Forfeited		$ 84.27
Nonvested, Shares/Units, Ending Balance		448,000.0	516,900
Nonvested, Weighted Average Grant Date Fair Value, End of Period		$ 86.56	$ 75.55
Stock Based Compensation (Textuals)
Maximum Contractual Term of Outstanding Restricted Stock Units (in months)		40 months
Total Aggregate Intrinsic Value of Nonvested Shares		$ 37,000,000
Weighted Average Remaining Contractual Life of Nonvested Shares (in years)		1.6 years
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology
Weighted Average Grant Date Fair Value		$ 94.38	$ 81.57	$ 67.96
Awarded Units		268,700	304,800	260,000.0
Performance Units [Member]
Performance Units
Awarded Units		424,800	535,000.0	581,400
Vesting Period (in years)		3 years	3 years	3 years
Certified Performance Scores and Units Earned
Certified Performance Score		128.20%	132.70%	136.70%
Performance Units Earned		757,858	792,897	820,780
Performance Units Manditorily Deferred as AEP Career Shares		13,614	10,063	11,248
Performance Units Voluntarily Deferred into the Incentive Compensation Deferral Program		26,936	49,392	56,826
Share Based Compensation Performance Units to be Settled in Shares	[5]	717,308	733,442
Performance Units to be Paid in Cash	[5]			752,706
Cash Payouts
Cash Payouts for Performance Units		$ 0	$ 58,300,000	$ 66,900,000
Equity Payouts for Performance Units		$ 75,400,000	0	0
Stock Based Compensation (Textuals)
Performance Score by HR Committee, Lower Range		0.00%
Performance Score by HR Committee, Higher Range		200.00%
Equity Payouts For Career Share Distributions		$ 1,900,000	$ 6,600,000	$ 5,100,000
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	[6]	2 years 10 months 13 days	2 years 10 months 13 days	2 years 10 months 13 days
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum		13.67%	14.83%	14.77%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum		28.15%	25.57%	26.72%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate		1.40%	2.49%	2.34%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	[7]	0.00%	0.00%	0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Weighted Average Volatility Rate		16.39%	17.39%	17.90%
Weighted Average Grant Date Fair Value		$ 116.56	$ 83.21	$ 67.21
Performance Units and Reinvested Dividends [Member]
Share Based Compensation Performance Units Converted to Shares	[8]	717,000
Performance Units
Awarded Units		53,800
Status of Nonvested Restricted Shares and Restricted Stock Units
Nonvested, Shares/Units, Beginning Balance		1,113,400
Nonvested, Weighted Average Grant Date Fair Value, Beginning of Period		$ 73.64
Shares/Units, Vested	[8]	(597,000.0)
Weighted Average Grant Date Fair Value, Vested		$ 66.45
Shares/Units, Forfeited		(56,400)
Weighted Average Grant Date Fair Value, Shares/Units, Forfeited		$ 87.58
Nonvested, Shares/Units, Ending Balance		938,600	1,113,400
Nonvested, Weighted Average Grant Date Fair Value, End of Period		$ 98.05	$ 73.64
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology
Weighted Average Grant Date Fair Value		$ 84.91
Severance Grant
Total Fair Value and Total Intrinsic Value of Restricted Shares and Restricted Stock Units Vested
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value		$ 5,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology
Weighted Average Grant Date Fair Value		$ 83.74
Awarded Units		64,186

[1] All awarded dividends in both 2020 and 2019 were equity awards and awarded dividends in 2018 were a mix of equity awards and liability awards.

[2] The vesting period for the reinvested dividends on performance shares is equal to the remaining life of the related performance shares.  Dividends on AEP career shares vest immediately when the dividend is awarded but are not settled in AEP common stock until after the participant’s AEP employment ends.

[3] Compensation cost for share-based payment arrangements is included in Other Operation and Maintenance expenses on the statements of income.

[4] Intrinsic value is calculated as market price at the vesting date.

[5] Performance shares settled for the three-year periods ended December 31, 2020 and 2019 settled in AEP common stock. Performance units settled for the three-year period ended December 31, 2018 settled in cash. In all cases, the settlement of common stock or cash occurs in the quarter following the end of the year shown.

[6] Period from award date to vesting date.

[7] Equivalent to reinvesting dividends.

[8] The vested Performance Shares will be converted to 717 thousand shares based on the closing share price on the day before settlement.