Derivative Instruments and Hedging Activities, Income Statement Presentation Related to Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Enogex [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount Recognized in Other Comprehensive Income	$ 0	$ 0.3
Amount Reclassifed from Accumulated Other Comprehensive Income (Loss) into Income	0	5.0
Amount Recognized in Income	0	0
Enogex [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount Recognized in Income	(0.3)	(2.0)
Enogex [Member] | Natural gas [Member] | Fixed Swaps/Futures [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount Recognized in Other Comprehensive Income	0	0.3
Amount Reclassifed from Accumulated Other Comprehensive Income (Loss) into Income	0.2	5.2
Amount Recognized in Income	0	0
Enogex [Member] | Natural gas [Member] | Fixed Swaps/Futures [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount Recognized in Income	(0.3)	0.4
Enogex [Member] | Sales [Member] | Natural gas [Member] | Physical [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount Recognized in Income		(2.4)
OGE Energy Corp. [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount Recognized in Other Comprehensive Income	0	0
Amount Reclassifed from Accumulated Other Comprehensive Income (Loss) into Income	(0.2)	(0.2)
Amount Recognized in Income	0	0
Maximum [Member] | Enogex [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Additional Collateral, Aggregate Fair Value	$ 0