Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Cash Flow Hedges, Tax	$ 11.8	$ 2.7	$ (16.8)	$ 3.9
Amortization of Pension and OPEB Deferred Costs, Tax	(0.4)	(0.4)	(1.1)	(1.1)
Appalachian Power Co [Member]
Cash Flow Hedges, Tax	(0.1)	(0.1)	(0.2)	(0.2)
Amortization of Pension and OPEB Deferred Costs, Tax	(0.2)	(0.2)	(0.5)	(0.6)
AEP Texas Inc. [Member]
Cash Flow Hedges, Tax	0.1	0.1	0.2	0.2
Amortization of Pension and OPEB Deferred Costs, Tax	0.0	0.0	0.0	0.0
Indiana Michigan Power Co [Member]
Cash Flow Hedges, Tax	0.1	0.1	0.3	0.3
Amortization of Pension and OPEB Deferred Costs, Tax	0.0	0.0	0.0	0.0
Ohio Power Co [Member]
Cash Flow Hedges, Tax	(0.1)	(0.1)	(0.3)	(0.3)
Public Service Co Of Oklahoma [Member]
Cash Flow Hedges, Tax	0.0	0.0	(0.2)	(0.2)
Southwestern Electric Power Co [Member]
Cash Flow Hedges, Tax	0.1	0.8	0.3	1.0
Amortization of Pension and OPEB Deferred Costs, Tax	$ 0.0	$ (0.1)	$ (0.2)	$ (0.3)