Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net Income (Loss)	$ 578.8	$ 499.3
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax	56.3	(67.0)
Amortization of Pension and OPEB Deferred Costs, Net of Tax	(2.0)	(1.8)
Other Comprehensive Income (Loss), Net of Tax, Total	54.3	(68.8)
TOTAL COMPREHENSIVE INCOME (LOSS)	633.1	430.5
Total Comprehensive Income (Loss) Attributable to Noncontrolling Interest	3.8	4.1
TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO COMMON SHAREHOLDERS	629.3	426.4
Cash Flow Hedges, Tax	15.0	(17.8)
Amortization of Pension and OPEB Deferred Costs, Tax	$ (0.5)	$ (0.5)
Common Stock, Dividends Per Share, Declared	$ 0.74	$ 0.70
Appalachian Power Co [Member]
Net Income (Loss)	$ 122.5	$ 115.3
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax	9.0	(4.2)
Amortization of Pension and OPEB Deferred Costs, Net of Tax	(1.1)	(0.9)
Other Comprehensive Income (Loss), Net of Tax, Total	7.9	(5.1)
TOTAL COMPREHENSIVE INCOME (LOSS)	130.4	110.2
Cash Flow Hedges, Tax	2.4	(1.1)
Amortization of Pension and OPEB Deferred Costs, Tax	(0.3)	(0.3)
AEP Texas Inc. [Member]
Net Income (Loss)	46.1	47.6
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax	0.3	0.3
Other Comprehensive Income (Loss), Net of Tax, Total	0.3	0.3
TOTAL COMPREHENSIVE INCOME (LOSS)	46.4	47.9
Cash Flow Hedges, Tax	0.1	0.1
Indiana Michigan Power Co [Member]
Net Income (Loss)	70.8	92.3
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax	0.5	0.4
Other Comprehensive Income (Loss), Net of Tax, Total	0.5	0.4
TOTAL COMPREHENSIVE INCOME (LOSS)	71.3	92.7
Cash Flow Hedges, Tax	0.1	0.1
Ohio Power Co [Member]
Net Income (Loss)	68.2	75.1
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax	0.0	0.0
TOTAL COMPREHENSIVE INCOME (LOSS)	68.2	75.1
Cash Flow Hedges, Tax	0.0	0.0
Public Service Co Of Oklahoma [Member]
Net Income (Loss)	(2.7)	(10.3)
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax	(0.1)	(0.2)
Other Comprehensive Income (Loss), Net of Tax, Total	(0.1)	(0.2)
TOTAL COMPREHENSIVE INCOME (LOSS)	(2.8)	(10.5)
Cash Flow Hedges, Tax	0.0	(0.1)
Southwestern Electric Power Co [Member]
Net Income (Loss)	63.4	16.1
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax	0.4	0.4
Amortization of Pension and OPEB Deferred Costs, Net of Tax	(0.4)	(0.4)
Other Comprehensive Income (Loss), Net of Tax, Total	0.0	0.0
TOTAL COMPREHENSIVE INCOME (LOSS)	63.4	16.1
Total Comprehensive Income (Loss) Attributable to Noncontrolling Interest	1.0	1.0
TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO COMMON SHAREHOLDERS	62.4	15.1
Cash Flow Hedges, Tax	0.1	0.1
Amortization of Pension and OPEB Deferred Costs, Tax	(0.1)	(0.1)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
OTHER COMPREHENSIVE INCOME
Other Comprehensive Income (Loss), Net of Tax, Total	(2.0)	(1.8)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | Appalachian Power Co [Member]
OTHER COMPREHENSIVE INCOME
Other Comprehensive Income (Loss), Net of Tax, Total	(1.1)	(0.9)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | AEP Texas Inc. [Member]
OTHER COMPREHENSIVE INCOME
Other Comprehensive Income (Loss), Net of Tax, Total	0.0	0.0
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | Indiana Michigan Power Co [Member]
OTHER COMPREHENSIVE INCOME
Other Comprehensive Income (Loss), Net of Tax, Total	0.0	0.0
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | Southwestern Electric Power Co [Member]
OTHER COMPREHENSIVE INCOME
Other Comprehensive Income (Loss), Net of Tax, Total	$ (0.4)	$ (0.4)