XML 193 R101.htm IDEA: XBRL DOCUMENT v3.8.0.1
Payroll, staff and employee benefits obligations - Sensitivity analysis (Details)
$ in Millions
Dec. 31, 2017
USD ($)
Discount rates  
Sensitivity analysis  
Increase in actuarial assumption (as a percent) 0.50%
Decrease in actuarial assumption (as a percent) 0.50%
Impact on benefit obligation from increase in actuarial assumption $ (857)
Impact on benefit obligation from decrease in actuarial assumption $ 974
Inflation rates  
Sensitivity analysis  
Increase in actuarial assumption (as a percent) 0.50%
Decrease in actuarial assumption (as a percent) 0.50%
Impact on benefit obligation from increase in actuarial assumption $ 637
Impact on benefit obligation from decrease in actuarial assumption $ (586)