Legal Proceedings and Other Contingencies	3 Months Ended
Mar. 31, 2025
Commitments and Contingencies Disclosure [Abstract]
Legal Proceedings and Other Contingencies	Legal Proceedings and Other Contingencies Various legal actions, claims, assessments and other contingencies arising in the ordinary course of business are pending against GATX and certain of our subsidiaries. These matters are subject to many uncertainties, and it is possible that some of these matters could ultimately be decided, resolved or settled adversely. Norfolk Southern Train Derailment in East Palestine, Ohio On June 30, 2023, a third-party complaint was filed by Norfolk Southern Railway Company and Norfolk Southern Corporation (collectively, “Norfolk Southern”) against GATX and several other parties in the Northern District of Ohio (Eastern Division) for contribution and recovery of environmental damages related to the derailment of a Norfolk Southern train in East Palestine, Ohio that included railcars owned by GATX Corporation. The Company filed a motion to dismiss Norfolk Southern's third-party complaint on September 15, 2023. On March 6, 2024, the Court granted GATX's and the other third-party defendants’ motions and dismissed all Comprehensive Environmental Response, Compensation and Liability Act ("CERCLA") claims. The Court also dismissed all state law claims, declining to exercise supplemental jurisdiction over them in light of its dismissal of the CERCLA claims. On March 26, 2024, Norfolk Southern moved the Court for entry of partial final judgment as to the order dismissing the third-party complaint in order to appeal before final judgment the Court’s dismissal order as to GATX and the other third-party defendants. The Court has not yet ruled on Norfolk Southern’s motion. In the interim, on May 23, 2024, Norfolk Southern entered into a Consent Decree settling claims with the United States Department of Justice and Environmental Protection Agency (but not the State of Ohio) to which GATX is not a party. On July 25, 2023, a separate third-party complaint was filed by Norfolk Southern against GATX and two other defendants in the Northern District of Ohio (Eastern Division) for contribution to personal injury and property damages class claims related to the derailment of the Norfolk Southern train in East Palestine, Ohio. The plaintiffs who had originally filed the complaint against Norfolk Southern ("Plaintiffs") themselves subsequently filed direct claims against GATX and the two other third-party defendants alleging many of the same facts as Norfolk Southern. On September 15, 2023, the Company filed a motion to dismiss Norfolk Southern's third-party complaint, and on September 26, 2023, filed a motion to dismiss the Plaintiffs' complaint. Briefing was completed on October 30, 2023, and the Court issued an order on March 13, 2024, denying in part, and granting in part, the Company’s motion against Norfolk Southern and Plaintiffs. The Court held that Norfolk Southern’s contribution action was premature and dismissed the claim without prejudice but otherwise allowed the remaining claims against GATX to proceed. The Court also dismissed Plaintiffs’ claim for medical monitoring but held that Plaintiffs could seek such damages through their other claims, which could proceed. The Court also consolidated an additional action filed against GATX and others titled Almasy, et al. v. Norfolk Southern Corp., et al. by over 40 individual residents, employees and property owners in East Palestine, Ohio. Plaintiffs and Norfolk Southern reached a settlement for $600 million to resolve the consolidated class action claims of those within a 20-mile radius from the derailment, and, for those residents who choose to participate, personal injury claims within a 10-mile radius from the derailment. On September 25, 2024, the Court held a final approval hearing and two days later issued its final approval order for the settlement. To date, a handful of appeals challenging the fairness, reasonableness and adequacy of the settlement have been filed with the Sixth Circuit Court of Appeals. On October 9, 2024, all parties to the litigation filed motions for summary judgment for the pending claims, which were denied in part and granted in part on February 21, 2025. Norfolk Southern requested and was granted leave to reinstate its contribution claims against GATX and others. Trial regarding Norfolk Southern's contribution claim against GATX and others began on March 31, 2025, and on April 23, 2025, the jury returned a verdict in favor of GATX finding no negligence by GATX and 0% liability. On December 8, 2023, GATX and three other defendants were named as additional defendants in a putative class action lawsuit originally filed in federal court in Pennsylvania against Norfolk Southern by four Pennsylvania school districts and their students. The allegations largely mirror those in the action filed in federal court in Ohio. The amended complaint seeks monetary damages for the Pennsylvania plaintiffs for personal injury and property damage allegedly related to the derailment. The Company and other defendants filed a motion to dismiss on February 23, 2024. Briefing has been completed and the motions remain pending and undecided. The Court has not set any further deadlines. GATX was named in two new lawsuits filed on February 3, 2025, in The Court of Common Plea, Franklin County, Ohio on behalf of approximately 750 plaintiffs of whom approximately 184 have opted out of the prior settlement agreements with Norfolk Southern or were not included and are now suing GATX and approximately 60 other defendants. The remaining plaintiffs who opted into the settlement with Norfolk Southern (approximately 550) are not suing GATX. GATX was named in one new lawsuit (Tsai) filed by the same plaintiffs in three different jurisdictions: Philadelphia (Pennsylvania state court), Cuyahoga (Ohio state court), and Lawrence (Pennsylvania state court). The allegations are similar to the allegations originally filed against GATX in the Ohio Personal Injury Litigation. Plaintiffs filed a Praecipe to Dismiss the action filed in Lawrence County in order to pursue the same action in Philadelphia. The current deadline for responding to the Philadelphia action is April 28, 2025. The Company is vigorously defending itself against each of these lawsuits. At this time, the Company cannot reasonably estimate the loss or range of loss, if any, that may ultimately be incurred in connection with any of these lawsuits and has not established any accruals for potential liability related to this incident. For a full discussion of our other pending legal matters, please refer to "Note 23. Legal Proceedings and Other Contingencies" in Part II, Item 8 of our Annual Report on Form 10-K for the year ended December 31, 2024.

On June 30, 2023, a third-party complaint was filed by Norfolk Southern Railway Company and Norfolk Southern Corporation (collectively, “Norfolk Southern”) against GATX and several other parties in the Northern District of Ohio (Eastern Division) for contribution and recovery of environmental damages related to the derailment of a Norfolk Southern train in East Palestine, Ohio that included railcars owned by GATX Corporation. The Company filed a motion to dismiss Norfolk Southern's third-party complaint on September 15, 2023. On March 6, 2024, the Court granted GATX's and the other third-party defendants’ motions and dismissed all Comprehensive Environmental Response, Compensation and Liability Act ("CERCLA") claims. The Court also dismissed all state law claims, declining to exercise supplemental jurisdiction over them in light of its dismissal of the CERCLA claims. On March 26, 2024, Norfolk Southern moved the Court for entry of partial final judgment as to the order dismissing the third-party complaint in order to appeal before final judgment the Court’s dismissal order as to GATX and the other third-party defendants. The Court has not yet ruled on Norfolk Southern’s motion. In the interim, on May 23, 2024, Norfolk Southern entered into a Consent Decree settling claims with the United States Department of Justice and Environmental Protection Agency (but not the State of Ohio) to which GATX is not a party.

On July 25, 2023, a separate third-party complaint was filed by Norfolk Southern against GATX and two other defendants in the Northern District of Ohio (Eastern Division) for contribution to personal injury and property damages class claims related to the derailment of the Norfolk Southern train in East Palestine, Ohio. The plaintiffs who had originally filed the complaint against Norfolk Southern ("Plaintiffs") themselves subsequently filed direct claims against GATX and the two other third-party defendants alleging many of the same facts as Norfolk Southern. On September 15, 2023, the Company filed a motion to dismiss Norfolk Southern's third-party complaint, and on September 26, 2023, filed a motion to dismiss the Plaintiffs' complaint. Briefing was completed on October 30, 2023, and the Court issued an order on March 13, 2024, denying in part, and granting in part, the Company’s motion against Norfolk Southern and Plaintiffs. The Court held that Norfolk Southern’s contribution action was premature and dismissed the claim without prejudice but otherwise allowed the remaining claims against GATX to proceed. The Court also dismissed Plaintiffs’ claim for medical monitoring but held that Plaintiffs could seek such damages through their other claims, which could proceed. The Court also consolidated an additional action filed against GATX and others titled Almasy, et al. v. Norfolk Southern Corp., et al. by over 40 individual residents, employees and property owners in East Palestine, Ohio. Plaintiffs and Norfolk Southern reached a settlement for $600 million to resolve the consolidated class action claims of those within a 20-mile radius from the derailment, and, for those residents who choose to participate, personal injury claims within a 10-mile radius from the derailment. On September 25, 2024, the Court held a final approval hearing and two days later issued its final approval order for the settlement. To date, a handful of appeals challenging the fairness, reasonableness and adequacy of the settlement have been filed with the Sixth Circuit Court of Appeals. On October 9, 2024, all parties to the litigation filed motions for summary judgment for the pending claims, which were denied in part and granted in part on February 21, 2025. Norfolk Southern requested and was granted leave to reinstate its contribution claims against GATX and others. Trial regarding Norfolk Southern's contribution claim against GATX and others began on March 31, 2025, and on April 23, 2025, the jury returned a verdict in favor of GATX finding no negligence by GATX and 0% liability.

On December 8, 2023, GATX and three other defendants were named as additional defendants in a putative class action lawsuit originally filed in federal court in Pennsylvania against Norfolk Southern by four Pennsylvania school districts and their students. The allegations largely mirror those in the action filed in federal court in Ohio. The amended complaint seeks monetary damages for the Pennsylvania plaintiffs for personal injury and property damage allegedly related to the derailment. The Company and other defendants filed a motion to dismiss on February 23, 2024. Briefing has been completed and the motions remain pending and undecided. The Court has not set any further deadlines.

GATX was named in one new lawsuit (Tsai) filed by the same plaintiffs in three different jurisdictions: Philadelphia (Pennsylvania state court), Cuyahoga (Ohio state court), and Lawrence (Pennsylvania state court). The allegations are similar to the allegations originally filed against GATX in the Ohio Personal Injury Litigation. Plaintiffs filed a Praecipe to Dismiss the action filed in Lawrence County in order to pursue the same action in Philadelphia. The current deadline for responding to the Philadelphia action is April 28, 2025.