Disposition Plant Severance (Details) - USD ($) $ in Thousands		6 Months Ended	12 Months Ended
		Jun. 30, 2015	Dec. 31, 2014
Severance Costs			$ 29,000
Vertically Integrated Utilities [Member]
Cost Reduction Initiatives Text [Abstract]
Current Period Severance Costs Percentage		68.00%
Generation And Marketing [Member]
Cost Reduction Initiatives Text [Abstract]
Current Period Severance Costs Percentage		32.00%
Disposition Plant Severance [Member]
Cost Reduction Initiatives [Abstract]
Beginning Balance		$ 29,000
Incurred		3,000
Settled		(11,000)
Adjustments		0
Remaining Balance		21,000	29,000
Appalachian Power Co [Member]
Severance Costs			7,112
Cost Reduction Initiatives [Abstract]
Beginning Balance		9,304
Expense Allocation from Aepsc		(5)
Incurred		817
Settled	[1]	(4,478)
Adjustments		(129)
Remaining Balance		5,509	9,304
Indiana Michigan Power Co [Member]
Severance Costs			8,185
Cost Reduction Initiatives [Abstract]
Beginning Balance		8,023
Expense Allocation from Aepsc		(3)
Incurred		363
Settled		(3,459)
Adjustments		0
Remaining Balance		4,924	8,023
Ohio Power Co [Member]
Severance Costs			80
Public Service Co Of Oklahoma [Member]
Severance Costs			288
Cost Reduction Initiatives [Abstract]
Beginning Balance		134
Expense Allocation from Aepsc		(3)
Incurred		416
Settled		(116)
Adjustments		0
Remaining Balance		431	134
Southwestern Electric Power Co [Member]
Severance Costs			289
Cost Reduction Initiatives [Abstract]
Beginning Balance		84
Expense Allocation from Aepsc		(4)
Incurred		0
Settled		(79)
Adjustments		0
Remaining Balance		$ 1	$ 84

[1] Settled includes amounts received from affiliates for expenses related to joint plant.