Noncontrolling Interests Contributions Table (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 units		Oct. 02, 2012	Dec. 31, 2011
OGE Holdings [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at December 31, 2011 (units)	93,800,000
Issuance of units of Enogex Holdings	2,700,000	[1]
Balance at December 31, 2012 (units)	96,500,000
Ownership percentage, OGE Holdings	79.90%			81.30%
Contributions Toward Meeting 2012 Captial Requirements			$ 45.0
ArcLight Group [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at December 31, 2011 (units)	21,600,000
Issuance of units of Enogex Holdings	2,600,000	[1]
Balance at December 31, 2012 (units)	24,200,000
Ownership percentage, ArcLight Group	20.10%			18.70%
Contributions Toward Meeting 2012 Captial Requirements			$ 45.0
Enogex Holdings [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at December 31, 2011 (units)	115,400,000
Issuance of units of Enogex Holdings	5,300,000	[1]
Balance at December 31, 2012 (units)	120,700,000
Total Ownership Percentage	100.00%			100.00%

[1] Effective October 1, 2012, OGE Energy and the ArcLight group made contributions to Enogex Holdings of $45.0 million each to fund a portion of Enogex LLC's 2012 capital requirements.