v3.25.2
Document and Entity Information - shares
6 Months Ended
Jun. 30, 2025
Aug. 01, 2025
Document and Entity Information [Abstract]    
Title of 12(b) Security Common Stock, par value $0.01  
Trading Symbol JLL  
Security Exchange Name NYSE  
Entity Incorporation, State or Country Code MD  
Entity Tax Identification Number 36-4150422  
Entity Address, Address Line One 200 East Randolph Drive  
Entity Address, City or Town Chicago,  
Entity Address, State or Province IL  
Entity Address, Postal Zip Code 60601  
Entity File Number 1-13145  
City Area Code (312)  
Local Phone Number 782-5800  
Document Quarterly Report true  
Document Transition Report false  
Entity Registrant Name Jones Lang LaSalle Incorporated  
Entity Central Index Key 0001037976  
Current Fiscal Year End Date --12-31  
Entity Shell Company false  
Entity Emerging Growth Company false  
Entity Small Business false  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   47,381,230
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q2  
Document Period End Date Jun. 30, 2025  
Document Type 10-Q  
Amendment Flag false