v3.26.3
Segments - Schedule of Summarized Financial Information by Segment (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Segment Reporting [Line Items]        
Depreciation and amortization $ 184 $ 145 $ 556 $ 432
Equity income from unconsolidated subsidiaries 104 52 99 50
Operating segments        
Segment Reporting [Line Items]        
Equity income from unconsolidated subsidiaries 104 52 99 50
Operating segments | Advisory Services        
Segment Reporting [Line Items]        
Depreciation and amortization 30 33 96 95
Equity income from unconsolidated subsidiaries 1 0 (2) 0
Operating segments | Building Operations & Experience        
Segment Reporting [Line Items]        
Depreciation and amortization 110 65 325 196
Equity income from unconsolidated subsidiaries 3 2 3 (14)
Operating segments | Project Management        
Segment Reporting [Line Items]        
Depreciation and amortization 26 27 78 78
Equity income from unconsolidated subsidiaries 0 0 0 0
Operating segments | Real Estate Investments        
Segment Reporting [Line Items]        
Depreciation and amortization 5 2 18 8
Equity income from unconsolidated subsidiaries 101 49 102 40
Corporate, other and eliminations        
Segment Reporting [Line Items]        
Depreciation and amortization 13 18 39 55
Equity income from unconsolidated subsidiaries $ (1) $ 1 $ (4) $ 24