Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Revenue from Contracts with Customers		$ 3,747.5	$ 4,056.8
Net Income (Loss)		499.3	574.1
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax		(67.0)	(28.9)
Amortization of Pension and OPEB Deferred Costs, Net of Tax		(1.8)	(1.4)
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)		(68.8)	(30.3)
TOTAL COMPREHENSIVE INCOME (LOSS)		430.5	543.8
Total Comprehensive Income (Loss) Attributable to Noncontrolling Interest		4.1	1.3
TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO COMMON SHAREHOLDERS		426.4	542.5
Appalachian Power Co [Member]
Net Income (Loss)		115.3	133.7
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax		(4.2)	(0.2)
Amortization of Pension and OPEB Deferred Costs, Net of Tax		(0.9)	(0.6)
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)		(5.1)	(0.8)
TOTAL COMPREHENSIVE INCOME (LOSS)		110.2	132.9
AEP Texas Inc. [Member]
Net Income (Loss)		47.6	34.4
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax		0.3	0.3
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)		0.3	0.3
TOTAL COMPREHENSIVE INCOME (LOSS)		47.9	34.7
Indiana Michigan Power Co [Member]
Net Income (Loss)		92.3	98.9
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax		0.4	0.4
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)		0.4	0.4
TOTAL COMPREHENSIVE INCOME (LOSS)		92.7	99.3
Ohio Power Co [Member]
Net Income (Loss)		75.1	128.0
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax		0.0	(0.3)
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)			(0.3)
TOTAL COMPREHENSIVE INCOME (LOSS)		75.1	127.7
Public Service Co Of Oklahoma [Member]
Net Income (Loss)		(10.3)	6.2
OTHER COMPREHENSIVE INCOME
Cash Flow Hedges, Net of Tax		(0.2)	(0.2)
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)		(0.2)	(0.2)
TOTAL COMPREHENSIVE INCOME (LOSS)		(10.5)	6.0
Southwestern Electric Power Co [Member]
Net Income (Loss)		16.1	29.0
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)	(0.3)
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)		0.0	0.1
TOTAL COMPREHENSIVE INCOME (LOSS)		16.1	29.1
Total Comprehensive Income (Loss) Attributable to Noncontrolling Interest		1.0	1.2
TOTAL COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO COMMON SHAREHOLDERS		15.1	27.9
Generation and Marketing Revenues [Member]
Revenue from Contracts with Customers		408.4	439.7
Reclassification out of Accumulated Other Comprehensive Income [Member] | Generation and Marketing Revenues [Member]
Revenue from Contracts with Customers	[1]	(0.1)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
OTHER COMPREHENSIVE INCOME
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)		(1.8)	(1.4)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | Appalachian Power Co [Member]
OTHER COMPREHENSIVE INCOME
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)		(0.9)	(0.6)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | AEP Texas Inc. [Member]
OTHER COMPREHENSIVE INCOME
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)		0.0	0.0
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | Indiana Michigan Power Co [Member]
OTHER COMPREHENSIVE INCOME
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)		0.0	0.0
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | Southwestern Electric Power Co [Member]
OTHER COMPREHENSIVE INCOME
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)		(0.4)	$ (0.3)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Generation and Marketing Revenues [Member]
Revenue from Contracts with Customers	[1]	$ 0.0

[1] (a) The change in fair value includes $5 million related to AEP's investment in joint venture wind farms acquired as part of the purchase of Sempra Renewables LLC for the three months ended March 31, 2020