Investments in associates - Summarized Aggregate Financial Information of Associates (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of associates [line items]
Earnings from associates – after interest and tax	$ 1,330	$ 994	$ 1,839
Investments in associates	16,991	14,092
Rosneft
Disclosure of associates [line items]
Earnings from associates – after interest and tax	922	647	1,330
Investments in associates	10,059	8,243
Other associates
Disclosure of associates [line items]
Earnings from associates – after interest and tax	408	347	509
Investments in associates	6,932	5,849
Associates
Disclosure of associates [line items]
Earnings from associates – after interest and tax	1,330	994	$ 1,839
Investments in associates	$ 16,991	$ 14,092

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

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- Definition

The amount of investments in associates accounted for using the equity method. [Refer: Associates [member]; Investments accounted for using equity method]

+ References

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- Definition

The entity's share of the profit (loss) of associates accounted for using the equity method. [Refer: Associates [member]; Investments accounted for using equity method; Profit (loss)]

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