Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Fair Value, by Balance Sheet Grouping [Table Text Block]

The following table summarizes the fair value and carrying amount of OG&E's financial instruments atDecember 31, 2016 and 2015.

Year Ended December 31 (In millions)	2016				2015
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Long-Term Debt (including Long-Term Debt due within one year)
Senior Notes	$	2,385.5	$	2,657.2	$	2,493.9	$	2,754.6
Industrial Authority Bonds	135.4		135.4		135.4		135.4
Tinker Debt	9.9		11.3		10.0		9.2