v3.19.3.a.u2
Document and Entity Information Statement
Feb. 07, 2020
Document Information [Line Items]  
Document Type 8-K
Document Period End Date Feb. 07, 2020
Entity Registrant Name GATX Corporation
Entity Incorporation, State or Country Code NY
Entity File Number 1-2328
Entity Tax Identification Number 36-1124040
Entity Address, Address Line One 233 South Wacker Drive
Entity Address, City or Town Chicago
Entity Address, State or Province IL
Entity Address, Postal Zip Code 60606
City Area Code 312
Local Phone Number 621-6200
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity Emerging Growth Company false
Amendment Flag false
Entity Central Index Key 0000040211
CHICAGO STOCK EXCHANGE, INC [Member]  
Document Information [Line Items]  
Security Exchange Name CHX
Common Stock [Member] | NEW YORK STOCK EXCHANGE, INC. [Member]  
Document Information [Line Items]  
Title of 12(b) Security Common Stock
Trading Symbol GATX
Security Exchange Name NYSE
Senior Notes [Member] | NEW YORK STOCK EXCHANGE, INC. [Member]  
Document Information [Line Items]  
Title of 12(b) Security 5.625% Senior Notes due 2066
Trading Symbol GMTA
Security Exchange Name NYSE