v3.26.3
Revenue from Contracts with Customers - Schedule of Disaggregation of Revenue from Contracts with Customers (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue $ 11,407 $ 10,090 $ 32,945 $ 28,463
Total Out of Scope of Topic 606 Revenue 110 131 325 350
Total Revenue 11,517 10,221 33,270 28,813
Facilities management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 5,401 4,771 15,941 14,024
Property management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 693 648 2,047 1,869
Critical infrastructure        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 744 414 1,998 1,155
Project management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 2,035 1,978 5,918 5,289
Advisory leasing        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 1,213 1,144 3,477 3,001
Advisory sales        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 697 545 1,761 1,364
Valuation        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 206 194 626 573
Other portfolio services        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 98 89 261 267
Commercial mortgage origination        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 78 58 206 154
Total Out of Scope of Topic 606 Revenue 23 42 73 89
Loan servicing        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 41 40 117 116
Total Out of Scope of Topic 606 Revenue 85 87 250 253
Investment management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 154 148 457 447
Development services        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 47 61 136 204
Total Out of Scope of Topic 606 Revenue 2 2 2 8
Operating segments        
Disaggregation of Revenue [Line Items]        
Total Revenue 11,517 10,221 33,270 28,813
Operating segments | Advisory Services        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 2,333 2,070 6,448 5,475
Total Out of Scope of Topic 606 Revenue 108 129 323 342
Total Revenue 2,441 2,199 6,771 5,817
Operating segments | Advisory Services | Advisory leasing        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 1,213 1,144 3,477 3,001
Operating segments | Advisory Services | Advisory sales        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 697 545 1,761 1,364
Operating segments | Advisory Services | Valuation        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 206 194 626 573
Operating segments | Advisory Services | Other portfolio services        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 98 89 261 267
Operating segments | Advisory Services | Commercial mortgage origination        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 78 58 206 154
Total Out of Scope of Topic 606 Revenue 23 42 73 89
Operating segments | Advisory Services | Loan servicing        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 41 40 117 116
Total Out of Scope of Topic 606 Revenue 85 87 250 253
Operating segments | Advisory Services | Development services        
Disaggregation of Revenue [Line Items]        
Total Out of Scope of Topic 606 Revenue 0      
Operating segments | Building Operations & Experience        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 6,856 5,842 20,033 17,068
Total Out of Scope of Topic 606 Revenue 0 0 0 0
Total Revenue 6,856 5,842 20,033 17,068
Operating segments | Building Operations & Experience | Facilities management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 5,401 4,771 15,941 14,024
Operating segments | Building Operations & Experience | Property management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 711 657 2,094 1,889
Operating segments | Building Operations & Experience | Critical infrastructure        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 744 414 1,998 1,155
Operating segments | Project Management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 2,035 1,978 5,918 5,289
Total Revenue 2,035 1,978 5,918 5,289
Operating segments | Project Management | Project management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 2,035 1,978 5,918 5,289
Operating segments | Real Estate Investments        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 201 209 593 651
Total Out of Scope of Topic 606 Revenue 2 2 2 8
Total Revenue 203 211 595 659
Operating segments | Real Estate Investments | Investment management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 154 148 457 447
Operating segments | Real Estate Investments | Development services        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 47 61 136 204
Total Out of Scope of Topic 606 Revenue 2 2 2 8
Corporate, other and eliminations        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue (18) (9) (47) (20)
Total Out of Scope of Topic 606 Revenue 0 0 0 0
Total Revenue (18) (9) (47) (20)
Corporate, other and eliminations | Property management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue $ (18) $ (9) $ (47) $ (20)