v3.26.1
Segments - Schedule of Segment Profit (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting [Line Items]        
Revenue $ 11,226 $ 9,717 $ 21,753 $ 18,592
Other adjustments to segment operating profit (loss):        
Equity (loss) income from unconsolidated subsidiaries 4 (18) (5) (2)
Other income (loss) 6 6 17 7
Gain on disposition of real estate 5 19 306 19
Operating income 365 374 876 650
Operating segments        
Segment Reporting [Line Items]        
Revenue 11,226 9,717 21,753 18,592
Pass-through costs 4,622 4,085 9,070 7,883
Cost of revenue, excluding pass-through costs 4,518 3,857 8,745 7,324
Operating expenses and allocations 1,536 1,275 2,996 2,467
Other adjustments to segment operating profit (loss):        
Equity (loss) income from unconsolidated subsidiaries 4 (18) (5) (2)
Other income (loss) 6 6 17 7
Gain on disposition of real estate 5 19 306 19
Other segment adjustments 270 121 401 224
Operating income 835 628 1,661 1,166
Corporate, other and eliminations        
Segment Reporting [Line Items]        
Revenue (4) (7) (29) (11)
Pass-through costs 0 0 0 0
Cost of revenue, excluding pass-through costs (2) 5 (4) 1
Operating expenses and allocations 206 177 406 360
Other adjustments to segment operating profit (loss):        
Equity (loss) income from unconsolidated subsidiaries 0 2 (3) 23
Other income (loss) 0 0 (1) (1)
Gain on disposition of real estate 0 0 20 0
Other segment adjustments 70 61 133 128
Operating income (138) (126) (282) (222)
Advisory Services | Operating segments        
Segment Reporting [Line Items]        
Revenue 2,306 1,959 4,330 3,618
Pass-through costs 8 13 16 25
Cost of revenue, excluding pass-through costs 1,358 1,151 2,539 2,106
Operating expenses and allocations 504 455 973 883
Other adjustments to segment operating profit (loss):        
Equity (loss) income from unconsolidated subsidiaries (2) (1) (3) 0
Other income (loss) 0 2 1 3
Gain on disposition of real estate 0 0 0 0
Other segment adjustments 15 6 24 19
Operating income 449 347 824 626
Building Operations & Experience | Operating segments        
Segment Reporting [Line Items]        
Revenue 6,686 5,833 13,177 11,226
Pass-through costs 3,534 3,188 7,047 6,147
Cost of revenue, excluding pass-through costs 2,461 2,063 4,832 3,985
Operating expenses and allocations 381 343 758 643
Other adjustments to segment operating profit (loss):        
Equity (loss) income from unconsolidated subsidiaries (2) (17) 0 (16)
Other income (loss) 5 3 16 4
Gain on disposition of real estate 0 0 0 0
Other segment adjustments 22 42 59 46
Operating income 335 267 615 485
Project Management | Operating segments        
Segment Reporting [Line Items]        
Revenue 2,045 1,717 3,883 3,311
Pass-through costs 1,080 884 2,007 1,711
Cost of revenue, excluding pass-through costs 686 603 1,337 1,150
Operating expenses and allocations 134 118 261 233
Other adjustments to segment operating profit (loss):        
Equity (loss) income from unconsolidated subsidiaries 0 0 0 0
Other income (loss) 1 1 1 1
Gain on disposition of real estate 0 0 0 0
Other segment adjustments 1 2 3 9
Operating income 147 115 282 227
Real Estate Investments | Operating segments        
Segment Reporting [Line Items]        
Revenue 193 215 392 448
Pass-through costs 0 0 0 0
Cost of revenue, excluding pass-through costs 15 35 41 82
Operating expenses and allocations 311 182 598 348
Other adjustments to segment operating profit (loss):        
Equity (loss) income from unconsolidated subsidiaries 8 (2) 1 (9)
Other income (loss) 0 0 0 0
Gain on disposition of real estate 5 19 286 19
Other segment adjustments 162 10 182 22
Operating income $ 42 $ 25 $ 222 $ 50