Common Equity Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2016	[1]	Sep. 30, 2016	[1]	Jun. 30, 2016	[1]	Mar. 31, 2016	[1]	Dec. 31, 2015	[1]	Sep. 30, 2015	[1]	Jun. 30, 2015	[1]	Mar. 31, 2015	[1]	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount																	0.0		0.0		0.0
Net income attributable to OGE Energy																	$ 338.2		$ 271.3		$ 395.8
Basic Average Common Shares Outstanding																	199.7		199.6		199.2
Contingently Issuable Shares (Performance and Restricted Stock Units)																	0.2		0.0		0.7
Diluted Average Common Shares Outstanding																	199.9		199.6		199.9
Earnings Per Share, Basic and Diluted [Abstract]
Basic earnings per average common share attributable to OGE Energy common shareholders	$ 0.29		$ 0.92		$ 0.35		$ 0.13		$ 0.15		$ 0.55		$ 0.44		$ 0.22		$ 1.69	[1]	$ 1.36	[1]	$ 1.99
Diluted earnings per average common share attributable to OGE Energy common shareholders	$ 0.29		$ 0.92		$ 0.35		$ 0.13		$ 0.15		$ 0.55		$ 0.44		$ 0.22		$ 1.69	[1]	$ 1.36	[1]	$ 1.98

[1] Due to the impact of dilution on the earnings per share calculation, quarterly earnings per share amounts may not add to the total.