Fair Value Measurements - Summary of Financial Instrument Measured at Fair Value On A Recurring Basis and Carrying Amount and Fair Value (Details) - USD ($) $ in Millions		Jun. 30, 2024	Dec. 31, 2023
OGE Energy Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt		$ 346.8	$ 0.0
Long-Term Debt, Fair Value		352.7	0.0
OGE Energy Term Loan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt		59.7	49.9
Long-Term Debt, Fair Value		60.0	50.0
OG&E Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt		4,147.6	4,146.0
Long-Term Debt, Fair Value		3,831.3	3,922.3
OG&E Revolving Credit Facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt		200.0	0.0
Long-Term Debt, Fair Value		200.0	0.0
OG&E Industrial Authority Bonds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt		135.4	135.4
Long-Term Debt, Fair Value		135.4	135.4
OG&E Tinker Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt	[1]	11.7	9.2
Long-Term Debt, Fair Value	[1]	$ 9.3	$ 7.1

[1] In June 2024, OG&E purchased additional distribution assets at Tinker Air Force Base for $2.6 million, which was a non-cash investing and financing activity.