XML 480 R96.htm IDEA: XBRL DOCUMENT v3.21.1
Payroll, staff and employee benefits obligations - Plans and risk management (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Payroll, staff and employee benefits obligations      
Charge recognized for defined contribution plans $ 135 $ 133 $ 130