Significant Accounting Matters (Details) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
	Aug. 06, 2020 USD ($)	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($) $ / shares shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Amounts Attributable to AEP Common Shareholders
Earnings Attributable to Common Shareholders		$ 520.8	$ 461.3	$ 1,016.0	$ 1,034.1
Weighted Average Number of Basic AEP Common Shares Outstanding | shares		495,655,053	493,584,347	495,125,961	493,447,477
Total Basic Earnings Per Share Attributable to AEP Common Shareholders | $ / shares		$ 1.05	$ 0.93	$ 2.05	$ 2.10
Weighted Average Dilutive Effect of:
Weighted Average Number of Diluted AEP Common Shares Outstanding | shares		497,337,980	495,382,966	496,973,449	494,934,320
Total Diluted Earnings Per Share Attributable to AEP Common Shareholders | $ / shares		$ 1.05	$ 0.93	$ 2.04	$ 2.09
Organization and Summary of Significant Accounting Policies (Textuals)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares				156,000	0
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		$ 348.8		$ 348.8		$ 246.8
Restricted Cash		155.9		155.9		185.8
Total Cash, Cash Equivalents and Restricted Cash		504.7	$ 389.7	504.7	$ 389.7	432.6	$ 444.1
Subsequent Event [Member]
Voluntary Retirement Incentive Program [Abstract]
Employees Participating in Voluntary Retirement Incentive Program	200
Percent of Voluntary Retirement Incentive Program Expense related to AEP Service Corporation	92.00%
Subsequent Event [Member] | Lump Sum Salary Payments and Cash Subsidies [Member]
Voluntary Retirement Incentive Program [Abstract]
Voluntary Retirement Incentive Program Expense	$ 13.0
Subsequent Event [Member] | Incremental Long-Term Incentive Plan Grants [Member]
Voluntary Retirement Incentive Program [Abstract]
Voluntary Retirement Incentive Program Expense	$ 5.0
AEP Texas Inc. [Member]
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		0.1		0.1		3.1
Restricted Cash		136.6		136.6		154.7
Total Cash, Cash Equivalents and Restricted Cash		136.7	125.5	136.7	125.5	157.8	159.8
AEP Transmission Co [Member]
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		0.0	0.0	0.0	0.0	0.0	0.0
Appalachian Power Co [Member]
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		2.5		2.5		3.3
Restricted Cash		19.3		19.3		23.5
Total Cash, Cash Equivalents and Restricted Cash		21.8	27.7	21.8	27.7	26.8	29.8
Indiana Michigan Power Co [Member]
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		2.0	1.4	2.0	1.4	2.0	2.4
Ohio Power Co [Member]
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		3.3		3.3		3.7
Total Cash, Cash Equivalents and Restricted Cash		3.3	30.9	3.3	30.9	3.7	32.5
Public Service Co Of Oklahoma [Member]
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		1.4	1.4	1.4	1.4	1.5	2.0
Southwestern Electric Power Co [Member]
Amounts Attributable to AEP Common Shareholders
Earnings Attributable to Common Shareholders		58.8	6.2	73.9	34.0
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents		$ 1.8	$ 24.0	$ 1.8	$ 24.0	$ 1.6	$ 24.5
Restricted Stock Units and Performance Share Units [Member]
Weighted Average Dilutive Effect of:
Weighted Average Dilutive Effect of Shares | shares		1,600,000	1,800,000	1,900,000	1,500,000
Dilutive Securities, Effect on Basic Earnings Per Share | $ / shares		$ 0	$ 0	$ (0.01)	$ (0.01)