Summary of Significant Accounting Policies, Equity Ownership (Details)			8 Months Ended
	Mar. 31, 2013 Atoka [Member]	Mar. 31, 2013 OGE Holdings [Member]	Dec. 31, 2013 OGE Energy [Member]	Dec. 31, 2013 CenterPoint [Member]	Dec. 31, 2013 ArcLight group [Member]
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	50.00%	79.90%
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest			28.50%	58.30%	13.20%