Fair Value Measurements Carrying and Fair Value Amounts (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
OG&E Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Carrying Amount	$ 2,683,000,000	$ 2,385,500,000
Long-Term Debt, Fair Value	2,941,500,000	2,657,200,000
OG&E Industrial Authority Bonds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Carrying Amount	135,400,000	135,400,000
Long-Term Debt, Fair Value	135,400,000	135,400,000
OG&E Tinker Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Carrying Amount	9,800,000	9,900,000
Long-Term Debt, Fair Value	9,300,000	9,500,000
OGE Energy Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Carrying Amount	99,800,000	99,700,000
Long-Term Debt, Fair Value	100,000,000	99,900,000
Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	$ 0	$ 0