Common Equity (Tables)

12 Months Ended

Dec. 31, 2012

Equity [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

Basic and diluted earnings per share for the Company were calculated as follows:

(In millions)	2012		2011		2010
Net Income Attributable to OGE Energy	$	355.0	$	342.9	$	295.3
Average Common Shares Outstanding
Basic average common shares outstanding	98.6		97.9		97.3
Effect of dilutive securities:
Contingently issuable shares (performance units)	0.5		1.3		1.6
Diluted average common shares outstanding	99.1		99.2		98.9
Basic Earnings Per Average Common Share Attributable to OGE Energy Common Shareholders	$	3.60	$	3.50	$	3.03
Diluted Earnings Per Average Common Share Attributable to OGE Energy Common Shareholders	$	3.58	$	3.45	$	2.99
Anti-dilutive shares excluded from earnings per share calculation	—		—		—