Investment in Unconsolidated Affiliates (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Jun. 30, 2014	Mar. 31, 2014
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest		6.90%
Enogex LLC [Member]
Percentage of Enogex LLC Contributed		100.00%
ArcLight group [Member]
Contributions to Pay Down Short-Term Debt		$ 107.0
OGE Holdings [Member]
Contributions to Pay Down Short-Term Debt		9.1
Units Held by Limited Partners of the LLC or LP.		42,832,291
OGE Energy [Member]
Percentage Share of Management Rights		50.00%
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	26.70%	28.50%
Percent of Incentive Distribution Rights		60.00%
CenterPoint [Member]
Percentage Share of Management Rights		50.00%
Percent of Incentive Distribution Rights		40.00%
Enable Midstream Partners [Member]
Partners' Capital Account, Units, Sold in Public Offering		28,750,000
Proceeds from Issuance Initial Public Offering		466.0
Distributions from unconsolidated affiliates		$ 32.5