Derivative Instruments and Hedging Activities, Income Statement Presentation Related to Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified		3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012 Enogex [Member] Cash Flow Hedging [Member]	Sep. 30, 2012 Enogex [Member] Cash Flow Hedging [Member]	Sep. 30, 2012 Enogex [Member] Not Designated as Hedging Instrument [Member]	Sep. 30, 2012 Enogex [Member] Not Designated as Hedging Instrument [Member]	Sep. 30, 2012 Enogex [Member] Natural gas [Member] Fixed Swaps/Futures [Member] Cash Flow Hedging [Member]	Sep. 30, 2012 Enogex [Member] Natural gas [Member] Fixed Swaps/Futures [Member] Cash Flow Hedging [Member]	Sep. 30, 2012 Enogex [Member] Natural gas [Member] Fixed Swaps/Futures [Member] Not Designated as Hedging Instrument [Member]	Sep. 30, 2012 Enogex [Member] Natural gas [Member] Fixed Swaps/Futures [Member] Not Designated as Hedging Instrument [Member]	Sep. 30, 2012 Enogex [Member] Sales [Member] Natural gas [Member] Physical [Member] Not Designated as Hedging Instrument [Member]	Sep. 30, 2012 Enogex [Member] Sales [Member] Natural gas [Member] Physical [Member] Not Designated as Hedging Instrument [Member]	Sep. 30, 2012 OGE Energy Corp. [Member] Interest Rate Swap [Member] Cash Flow Hedging [Member]	Sep. 30, 2012 OGE Energy Corp. [Member] Interest Rate Swap [Member] Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount Recognized in Other Comprehensive Income		$ (0.8)	$ (1.0)			$ (0.8)	$ (1.0)					$ 0	$ 0
Amount Reclassifed from Accumulated Other Comprehensive Income (Loss) into Income		(0.1)	4.9			0	5.2					(0.1)	(0.3)
Amount Recognized in Income		0	0	(2.9)	(8.0)	0	0	(0.2)	0.8	(2.7)	(8.8)	0	0
Derivative Instruments With Credit Risk Related Contingent Features	$ 0