Stock-Based Compensation - Schedule of Pre-tax Compensation Expense and Related Income Tax Benefit (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense	$ 3.6	$ 3.3	$ 6.6	$ 6.5
Income tax benefit	0.9	0.8	1.6	1.6
OG&E [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense	3.6	3.3	6.6	6.5
Income tax benefit	0.9	0.8	1.6	1.6
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense	2.5	2.2	4.6	4.4
Performance Units [Member] | OG&E [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense	2.5	2.2	4.6	4.4
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense	1.1	1.1	2.0	2.1
Restricted Stock Units (RSUs) [Member] | OG&E [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense	$ 1.1	$ 1.1	$ 2.0	$ 2.1