INVESTMENTS - Equity Accounting Method Investment Continuity (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Disclosure of joint ventures [line items]
Investments, beginning balance		$ 1,213
Equity pick-up (loss) from equity investees		(46)	$ (76)
Impairment charges (reversals) (note 10)		900	(212)
Investments, ending balance		1,234	1,213
Joint ventures
Disclosure of joint ventures [line items]
Investments, beginning balance		1,213	1,185
Equity pick-up (loss) from equity investees		(46)	76
Funds invested		(5)	12
Impairment charges (reversals) (note 10)		(30)
Funds invested			60
Investments, ending balance		1,234	1,213
Kabanga
Disclosure of joint ventures [line items]
Investments, beginning balance		30	30
Equity pick-up (loss) from equity investees		0	(1)
Funds invested		0	1
Impairment charges (reversals) (note 10)	$ 30	(30)
Funds invested			0
Investments, ending balance		0	30
Jabal Sayid
Disclosure of joint ventures [line items]
Investments, beginning balance		206	180
Equity pick-up (loss) from equity investees		(39)	26
Funds invested		0	0
Impairment charges (reversals) (note 10)		0
Funds invested			0
Investments, ending balance		245	206
Zaldívar
Disclosure of joint ventures [line items]
Investments, beginning balance		975	974
Equity pick-up (loss) from equity investees		(14)	61
Funds invested		0	0
Impairment charges (reversals) (note 10)		0
Funds invested			60
Investments, ending balance		989	975
GNX
Disclosure of joint ventures [line items]
Investments, beginning balance		2	1
Equity pick-up (loss) from equity investees		7	(10)
Funds invested		(5)	11
Impairment charges (reversals) (note 10)		0
Funds invested			0
Investments, ending balance		$ 0	$ 2

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Investments accounted for using equity method, dividend

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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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