v3.25.1
Accelerating Aon United Program - Program Costs Incurred (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Restructuring Cost and Reserve [Line Items]    
Charges $ 110 $ 119
Accelerating Aon United Program    
Restructuring Cost and Reserve [Line Items]    
Charges 110 119
Accelerating Aon United Program | Corporate    
Restructuring Cost and Reserve [Line Items]    
Charges 87 65
Risk Capital | Accelerating Aon United Program | Operating Segments    
Restructuring Cost and Reserve [Line Items]    
Charges 19 43
Human Capital | Accelerating Aon United Program | Operating Segments    
Restructuring Cost and Reserve [Line Items]    
Charges $ 4 $ 11