Revenue from Contracts with Customers (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	[1]	$ 578.1	$ 1,621.0
Residential
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		226.8	568.2
Commercial
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		128.1	307.5
Industrial
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		57.4	146.7
Oilfield
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		53.2	160.8
Public authorities and street light
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		48.0	123.1
System sales revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		513.5	1,306.3
Provision for tax refund
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		(0.6)	0.0
Integrated market
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		22.8	302.1
Transmission
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		35.8	36.3
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		$ 6.6	$ (23.7)

[1] In February 2021, Winter Storm Uri resulted in record winter peak demand for electricity and extremely high natural gas and purchased power prices in OG&E's service territory. Operating revenues for the three months ended March 31, 2021 significantly increased due to increased fuel, purchased power and direct transmission expenses, which are generally recoverable from customers, as a result of Winter Storm Uri. For further discussion, see Note 14 and "Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operation."