Group statement of comprehensive income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of comprehensive income [abstract]
Gains on valuation of available-for-sale financial assets, tax	$ 0	$ (3)	$ 0
Gains on cash flow hedges, tax	1	0	0
Exchange (losses)/gains on retranslation of foreign operations, tax	2	1	(3)
Losses on valuation of assets classified as fair value through other comprehensive income, tax	(2)	0	0
Re-measurement (losses)/gains on defined benefit plans, related tax credit/(charge)	$ (4)	$ 0	$ 4

The amount of income tax relating to amounts recognised in other comprehensive income in relation to available-for-sale financial assets. [Refer: Financial assets available-for-sale; Other comprehensive income]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2021-01-01
-Name IAS
-Number 12
-IssueDate 2018-01-01
-Paragraph 81
-Subparagraph ab
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=12&date=2017-03-02&anchor=para_81_ab&doctype=Standard&book=b_pdf
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2021-01-01
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 90
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-02&anchor=para_90&doctype=Standard&book=b_pdf
-URIDate 2018-03-16

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- Definition

The amount of income tax relating to amounts recognised in other comprehensive income in relation to cash flow hedges. [Refer: Cash flow hedges [member]; Other comprehensive income]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 12
-IssueDate 2018-01-01
-Paragraph 81
-Subparagraph ab
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=12&date=2018-03-01&anchor=para_81_ab&doctype=Standard
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 90
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_90&doctype=Standard
-URIDate 2018-03-16

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- Definition

The amount of income tax relating to amounts recognised in other comprehensive income in relation to exchange differences on the translation of financial statements of foreign operations. [Refer: Other comprehensive income; Reserve of exchange differences on translation]

+ References

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- Definition

The amount of income tax relating to amounts recognised in other comprehensive income in relation to investments in equity instruments that the entity has designated at fair value through other comprehensive income. [Refer: Other comprehensive income; Reserve of gains and losses from investments in equity instruments]

+ References

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- Definition

The amount of income tax relating to amounts recognised in other comprehensive income in relation to remeasurements of defined benefit plans. [Refer: Other comprehensive income; Reserve of remeasurements of defined benefit plans; Defined benefit plans [member]]

+ References

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- References

No definition available.

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