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Operations and Significant Accounting Policies - Other Income (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022
Other Income |  |  |  |
Total Other Income | $ 68.7 | $ 2.3 | $ 75.3 | $ 16.4
Pension and Other Postretirement Benefit Plan Non-Service Credits |  |  |  |
Other Income |  |  |  |
Total Other Income | 1.8 | 1.9 | 5.5 | 7.2
Interest and Investment Income (b) |  |  |  |
Other Income |  |  |  |
Total Other Income | 6.6 | (0.4) | 8.7 | (1.3)
AFUDC - Equity |  |  |  |
Other Income |  |  |  |
Total Other Income | 1.1 | 0.7 | 2.5 | 2.4
PSA Liability |  |  |  |
Other Income |  |  |  |
Total Other Income | 0.0 | 0.0 | 0.0 | 10.2
Arbitration Award |  |  |  |
Other Income |  |  |  |
Total Other Income | 58.4 | 0.0 | 58.4 | 0.0
Other |  |  |  |
Other Income |  |  |  |
Total Other Income | 0.8 | $ 0.1 | 0.2 | $ (2.1)
Interest Income Related To Interest Awarded As Part Of An Arbitration Ruling |  |  |  |
Other Income |  |  |  |
Total Other Income | $ 5.1 |  | $ 5.1 |

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- Definition Amount of income (expense) related to nonoperating activities, classified as other. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.9) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2 + Details
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