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Fair Value Disclosure Fair Value Disclosure - Other Financial Instruments (Details) - USD ($) $ in Millions | Jun. 30, 2023 | Dec. 31, 2022
--- | --- | ---
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | $ 9.7 | $ 40.0
Short-Term Investments | 0.0 | 148.5
Reported Value Measurement [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Recourse Fixed Rate Debt Fair Value Disclosure | 6,248.3 | 6,045.1
Recourse Floating Rate Debt Fair Value Disclosure | 570.0 | 417.8
Estimate of Fair Value Measurement [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Recourse Fixed Rate Debt Fair Value Disclosure | 5,564.2 | 5,309.8
Recourse Floating Rate Debt Fair Value Disclosure | $ 567.9 | $ 417.0

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