Employee compensation and benefits - Employee compensation and benefits (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee Compensation And Benefits [Abstract]
Wages and salaries	$ 14,751	$ 15,227	$ 15,735
Social security costs	1,490	1,419	1,312
Post-employment benefits	1,132	669	1,042
Employee compensation and benefits	$ 17,373	$ 17,315	$ 18,089

Employee Compensation And Benefits [Abstract]

No definition available.

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- Definition

Post-Employment Benefit Expense, Defined Benefit Plans, Defined Contribution Plans, And Defined Benefit And Contribution Healthcare Plans

+ References

No definition available.

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- Definition

The expense of all forms of consideration given by an entity in exchange for a service rendered by employees or for the termination of employment.

+ References

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- Definition

A class of employee benefits expense that represents social security contributions. [Refer: Employee benefits expense]

+ References

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- Definition

A class of employee benefits expense that represents wages and salaries. [Refer: Employee benefits expense]

+ References

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