13.Employee benefits (Details Narrartive) - Performance Award Program [Member] - US - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2020	Jun. 30, 2020
Disclosure of net defined benefit liability (asset) [line items]
Final payment	$ 147
Additional provision		$ 311

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.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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