Common Equity Earnings Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Net income attributable to OGE Energy	$ 58.4		$ 187.3		$ 100.8		$ 49.3		$ 57.6		$ 215.2		$ 91.7		$ 23.1		$ 395.8		$ 387.6		$ 355.0
Basic Average Common Shares Outstanding																	199.2		198.2		197.1
Contingently Issuable Shares (Performance Units)																	0.7		1.2		1.0
Diluted Average Common Shares Outstanding																	199.9		199.4		198.1
Earnings Per Share, Basic and Diluted [Abstract]
Basic earnings per average common share attributable to OGE Energy common shareholders	$ 0.29	[1]	$ 0.94	[1]	$ 0.51	[1]	$ 0.25	[1]	$ 0.29	[1]	$ 1.08	[1]	$ 0.46	[1]	$ 0.12	[1]	$ 1.99	[1]	$ 1.96	[1]	$ 1.80
Diluted earnings per average common share attributable to OGE Energy common shareholders	$ 0.29	[1]	$ 0.94	[1]	$ 0.50	[1]	$ 0.25	[1]	$ 0.29	[1]	$ 1.08	[1]	$ 0.46	[1]	$ 0.12	[1]	$ 1.98	[1]	$ 1.94	[1]	$ 1.79
OGE Energy [Member]
Ratio of Consolidated Debt to Consolidated Capitalization	65.00%																65.00%
Retained Earnings, Restricted	452.6																452.6
Retained Earnings, Unrestricted	1,700.0																1,700.0
Og and E [Member]
Ratio of Consolidated Debt to Consolidated Capitalization	65.00%																65.00%
Retained Earnings, Restricted	412.2																412.2
Retained Earnings, Unrestricted	$ 1,600.0																$ 1,600.0

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