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Investments in Affiliated Companies (Textual) (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 USD ($) AircraftEngines Business_Activity | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
Schedule of Equity Method Investments [Line Items] |  |  |
Asset Impairment Charges | $ 0.0 | $ 1.5 | $ 48.9
Share of affiliates' earnings (net of tax) | 82.8 | 72.4 | 33.6
Portfolio proceeds | $ 230.6 | 272.8 | 269.6
RRPF Joint Ventures [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
GATX ownership percentage in joint venture | 50.00% |  |
Number of business activities | Business_Activity | 2 |  |
Number of Aircraft Engines Under Leasing Arrangement | AircraftEngines | 427 |  |
Share of affiliates' earnings (net of tax) | $ 82.8 | 72.8 | 33.2
RRPF Joint Ventures [Member] | Russia |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Asset Impairment Charges |  |  | 11.5
RRPF Joint Ventures [Member] | Rolls-Royce [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Number of Aircraft Engines Under Leasing Arrangement | AircraftEngines | 198 |  |
RRPF Joint Ventures [Member] | Minimum [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Lease term | 5 years |  |
RRPF Joint Ventures [Member] | Maximum [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Lease term | 12 years |  |
RRPF Joint Ventures [Member] | Aircraft Engines [Member] | Minimum [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Estimated useful lives of depreciable assets | 20 years |  |
RRPF Joint Ventures [Member] | Aircraft Engines [Member] | Maximum [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Estimated useful lives of depreciable assets | 30 years |  |
Portfolio Management [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Asset Impairment Charges | $ 0.0 | $ 1.2 | $ 34.3

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