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, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense	$ 3.3	$ 3.3	$ 6.5	$ 6.3
Income tax benefit	0.8	0.8	1.6	1.5
OG&E [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense	3.3	0.9	6.5	1.5
Income tax benefit	0.8	0.2	1.6	0.3
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense	2.2	2.3	4.4	4.5
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense	1.1	1.0	2.1	1.8
Restricted Stock Units (RSUs) [Member] | OG&E [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense	1.1	0.3	2.1	0.4
Total Shareholder Return [Member] | Performance Units [Member] | OG&E [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense	$ 2.2	$ 0.6	$ 4.4	$ 1.1