Income Taxes (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Valuation Allowance	$ 130
Income Taxes (Textuals) [Abstract]
Transmission and Distribution Expenses Net Income Adjustment	10
Public Service Co Of Oklahoma [Member]
Income Taxes (Textuals) [Abstract]
Transmission and Distribution Expenses Net Income Adjustment	1
Southwestern Electric Power Co [Member]
Income Taxes (Textuals) [Abstract]
Transmission and Distribution Expenses Net Income Adjustment	$ 5