Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	27,278
Stock-Based Compensation Activity
Income tax benefit	$ 0.6	$ 0.6
OG&E [Member]
Stock-Based Compensation Activity
Income tax benefit	$ 0.2	0.1
Total Shareholder Return [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	216,437
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 41.10
Total Shareholder Return [Member] \| OG&E [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	60,923
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 41.10
Restricted stock units
Stock-Based Compensation Activity
Compensation expense	$ 0.5	0.5
Restricted stock units \| OG&E [Member]
Stock-Based Compensation Activity
Compensation expense	0.2	0.0
Share-based Payment Arrangement [Member]
Stock-Based Compensation Activity
Compensation expense	2.3	2.5
Share-based Payment Arrangement [Member] \| OG&E [Member]
Stock-Based Compensation Activity
Compensation expense	$ 0.8	0.4
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	116,539
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 35.72
Restricted Stock Units (RSUs) [Member] \| OG&E [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	32,804
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 35.72
Total Shareholder Return [Member] \| Performance Shares [Member]
Stock-Based Compensation Activity
Compensation expense	$ 1.8	2.0
Total Shareholder Return [Member] \| Performance Shares [Member] \| OG&E [Member]
Stock-Based Compensation Activity
Compensation expense	$ 0.6	$ 0.4

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Net number of non-option equity instruments granted to participants.

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