Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2015

Fair Value Disclosures [Abstract]

Schedule of Fair Value and Carrying Amount of PRM Financial Instruments [Table Text Block]

The following table summarizes the fair value and carrying amount of the Company's financial instruments at June 30, 2015 and December 31, 2014.

	June 30, 2015				December 31, 2014
(In millions)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Long-Term Debt
OG&E Senior Notes	$	2,509.9	$	2,811.6	$	2,509.7	$	2,957.7
OG&E Industrial Authority Bonds	135.4		135.4		135.4		135.4
OG&E Tinker Debt	10.1		9.1		10.2		10.3
OGE Energy Senior Notes	100.0		99.9		100.0		99.9