v3.26.1
Revenue from Contracts with Customers - Schedule of Disaggregation of Revenue from Contracts with Customers (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue $ 11,114 $ 9,596 $ 21,538 $ 18,368
Total Out of Scope of Topic 606 Revenue 112 121 215 224
Total Revenue 11,226 9,717 21,753 18,592
Facilities management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 5,311 4,784 10,540 9,253
Property management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 695 639 1,354 1,221
Critical infrastructure        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 676 403 1,254 741
Project management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 2,045 1,717 3,883 3,311
Advisory leasing        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 1,229 995 2,264 1,857
Advisory sales        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 551 459 1,064 819
Valuation        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 220 196 420 379
Other portfolio services        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 88 97 163 178
Commercial mortgage origination        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 67 54 128 91
Total Out of Scope of Topic 606 Revenue 30 36 50 52
Loan servicing        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 39 37 76 76
Total Out of Scope of Topic 606 Revenue 82 85 165 166
Investment management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 149 145 303 299
Development services        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 44 70 89 143
Total Out of Scope of Topic 606 Revenue 0 0 0 6
Operating segments        
Disaggregation of Revenue [Line Items]        
Total Revenue 11,226 9,717 21,753 18,592
Operating segments | Advisory Services        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 2,194 1,838 4,115 3,400
Total Out of Scope of Topic 606 Revenue 112 121 215 218
Total Revenue 2,306 1,959 4,330 3,618
Operating segments | Advisory Services | Advisory leasing        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 1,229 995 2,264 1,857
Operating segments | Advisory Services | Advisory sales        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 551 459 1,064 819
Operating segments | Advisory Services | Valuation        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 220 196 420 379
Operating segments | Advisory Services | Other portfolio services        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 88 97 163 178
Operating segments | Advisory Services | Commercial mortgage origination        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 67 54 128 91
Total Out of Scope of Topic 606 Revenue 30 36 50 52
Operating segments | Advisory Services | Loan servicing        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 39 37 76 76
Total Out of Scope of Topic 606 Revenue 82 85 165 166
Operating segments | Building Operations & Experience        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 6,686 5,833 13,177 11,226
Total Out of Scope of Topic 606 Revenue 0 0 0 0
Total Revenue 6,686 5,833 13,177 11,226
Operating segments | Building Operations & Experience | Facilities management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 5,311 4,784 10,540 9,253
Operating segments | Building Operations & Experience | Property management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 699 646 1,383 1,232
Operating segments | Building Operations & Experience | Critical infrastructure        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 676 403 1,254 741
Operating segments | Project Management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 2,045 1,717 3,883 3,311
Total Revenue 2,045 1,717 3,883 3,311
Operating segments | Project Management | Project management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 2,045 1,717 3,883 3,311
Operating segments | Real Estate Investments        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 193 215 392 442
Total Out of Scope of Topic 606 Revenue 0 0 0 6
Total Revenue 193 215 392 448
Operating segments | Real Estate Investments | Investment management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 149 145 303 299
Operating segments | Real Estate Investments | Development services        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue 44 70 89 143
Total Out of Scope of Topic 606 Revenue 0 0 0 6
Corporate, other and eliminations        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue (4) (7) (29) (11)
Total Out of Scope of Topic 606 Revenue 0 0 0 0
Total Revenue (4) (7) (29) (11)
Corporate, other and eliminations | Property management        
Disaggregation of Revenue [Line Items]        
Topic 606 Revenue $ (4) $ (7) $ (29) $ (11)