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Retirement Plans and Postretirement Benefit Plans - Schedule of Allocation of Plan Assets (Details) - Other Postretirement Benefits Plan [Member] - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
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Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | $ 32.7 | $ 32.8 | $ 44.3
Og and E [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | 29.6 | 29.8 | $ 39.9
Group Retiree Medical Insurance Contract [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | 16.8 | 21.6 |
Mutual fund [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | 15.9 | 11.2 |
Fair Value, Inputs, Level 1 [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | 15.9 | 11.2 |
Fair Value, Inputs, Level 1 [Member] | Group Retiree Medical Insurance Contract [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | 0.0 | 0.0 |
Fair Value, Inputs, Level 1 [Member] | Mutual fund [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | 15.9 | 11.2 |
Fair Value, Inputs, Level 3 [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | 16.8 | 21.6 |
Fair Value, Inputs, Level 3 [Member] | Group Retiree Medical Insurance Contract [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | 16.8 | 21.6 |
Fair Value, Inputs, Level 3 [Member] | Mutual fund [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | 0.0 | 0.0 |
Fair Value, Inputs, Level 1, 2 and 3 [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | 32.7 | 32.8 |
Fair Value, Inputs, Level 1, 2 and 3 [Member] | OGE Energy [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | (3.1) | (3.0) |
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Og and E [Member] |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair Value of Plan Assets | $ 29.6 | $ 29.8 |

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