Leases - Schedule of Financial Statement Information of Lease Liabilities (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Leased Assets [Line Items]
Operating lease cost		$ 5.9	$ 6.3	$ 6.4
Operating cash flows for operating leases		5.3	6.3	6.4
Right-of-use assets obtained in exchange for new operating lease liabilities		1.5	0.0	1.4
Right-of-use assets at period end	[1]	$ 30.2	$ 33.0
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]		Property, Plant and Equipment, Net	Property, Plant and Equipment, Net
Operating lease liabilities at period end	[2]	$ 34.8	$ 37.6
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]		Liabilities, Other than Long-term Debt, Noncurrent	Liabilities, Other than Long-term Debt, Noncurrent
Operating lease weighted-average remaining lease term (in years)		11 years 7 months 6 days	12 years 2 months 12 days
Operating lease weighted-average discount rate		4.00%	3.90%
OG&E [Member]
Operating Leased Assets [Line Items]
Operating lease cost		$ 5.9	$ 5.7	5.5
Operating cash flows for operating leases		5.3	5.7	5.5
Right-of-use assets obtained in exchange for new operating lease liabilities		1.5	0.0	$ 1.4
Right-of-use assets at period end	[1]	$ 30.2	$ 33.0
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]		Property, Plant and Equipment, Net	Property, Plant and Equipment, Net
Operating lease liabilities at period end	[2]	$ 34.8	$ 37.6
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]		Liabilities, Other than Long-term Debt, Noncurrent	Liabilities, Other than Long-term Debt, Noncurrent
Operating lease weighted-average remaining lease term (in years)		11 years 7 months 6 days	12 years 2 months 12 days
Operating lease weighted-average discount rate		4.00%	3.90%

[1] Included in Property, Plant and Equipment in the Registrants' balance sheets.

[2] Included in Other Deferred Credits and Other Liabilities in the Registrants' balance sheets.