v3.26.3
Accelerating Aon United Program - Schedule of Program Costs Incurred (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Restructuring Cost and Reserve [Line Items]        
Charges $ 93 $ 32 $ 281 $ 236
Accelerating Aon United Program        
Restructuring Cost and Reserve [Line Items]        
Charges 93 32 281 236
Accelerating Aon United Program | Corporate        
Restructuring Cost and Reserve [Line Items]        
Charges 73 36 224 179
Risk Capital | Accelerating Aon United Program | Operating Segments        
Restructuring Cost and Reserve [Line Items]        
Charges 18 (3) 51 48
Human Capital | Accelerating Aon United Program | Operating Segments        
Restructuring Cost and Reserve [Line Items]        
Charges $ 2 $ (1) $ 6 $ 9