INVESTMENTS - Equity Accounting Method Investment Continuity (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Disclosure of joint ventures [line items]
Investments, beginning balance	$ 1,185
Equity pick-up (loss) from equity investees	(76)	$ (20)
Impairment reversals (note 10)	(212)	(250)
Investments, ending balance	1,213	1,185
Joint ventures
Disclosure of joint ventures [line items]
Investments, beginning balance	1,185	1,199
Equity pick-up (loss) from equity investees	76	20
Funds invested	12	9
Working capital adjustments		6
Impairment reversals (note 10)		(49)
Dividend	(60)
Investments, ending balance	1,213	1,185
Kabanga
Disclosure of joint ventures [line items]
Investments, beginning balance	30	30
Equity pick-up (loss) from equity investees	(1)	(1)
Funds invested	1	1
Working capital adjustments		0
Impairment reversals (note 10)		0
Dividend	0
Investments, ending balance	30	30
Jabal Sayid
Disclosure of joint ventures [line items]
Investments, beginning balance	180	178
Equity pick-up (loss) from equity investees	26	2
Funds invested	0	0
Working capital adjustments		0
Impairment reversals (note 10)		0
Dividend	0
Investments, ending balance	206	180
Zaldívar
Disclosure of joint ventures [line items]
Investments, beginning balance	974	990
Equity pick-up (loss) from equity investees	61	27
Funds invested	0	0
Working capital adjustments		6
Impairment reversals (note 10)		(49)
Dividend	(60)
Investments, ending balance	975	974
GNX
Disclosure of joint ventures [line items]
Investments, beginning balance	1	1
Equity pick-up (loss) from equity investees	(10)	(8)
Funds invested	11	8
Working capital adjustments		0
Impairment reversals (note 10)		0
Dividend	0
Investments, ending balance	$ 2	$ 1

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Investments accounted for using equity method, acquired

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The amount of impairment loss, impairment gain or reversal of impairment loss that is recognised in profit or loss in accordance with paragraph 5.5.8 of IFRS 9 and that arises from applying the impairment requirements in Section 5.5 of IFRS 9.

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The amount of investments accounted for using the equity method. The equity method is a method of accounting whereby the investment is initially recognised at cost and adjusted thereafter for the post-acquisition change in the investor's share of net assets of the investee. The investor's profit or loss includes its share of the profit or loss of the investee. The investor's other comprehensive income includes its share of the other comprehensive income of the investee. [Refer: At cost [member]]

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