Debt (Details 1) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Maturities of GATX's debt obligations
2016	$ 500.0
2017	519.5
2018	514.1
2019	454.9
2020	417.8
Thereafter	4,085.9
Total debt principal	6,492.2	$ 5,930.0
Balance	$ 17.3	$ 18.1
Short-term Debt, Weighted Average Interest Rate, at Point in Time	2.74%	0.84%

Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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