Investments Accounted for Using the Equity Method - Summary of Financial Information of Significant Equity Accounted Investments (Detail) - USD ($) $ in Millions	12 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Disclosure of significant investments in associates and joint ventures [line items]
Carrying amount of investments accounted for using the equity method	$ 2,585	$ 2,569	$ 2,473
Impairment of the carrying value of the investment in Samarco	(494)	(264)	(333)
Profit/(loss) from equity accounted investments, related impairments and expenses	(512)	(546)	147
Dividends received from equity accounted investments	126
Compania Minera Antamina S.A. [member]
Disclosure of significant investments in associates and joint ventures [line items]
Current assets	974	1,065
Non-current assets	4,743	4,495
Current liabilities	(239)	(498)
Non-current liabilities	(1,173)	(1,076)
Net assets/(liabilities) - 100%	4,305	3,986
Net assets/(liabilities) - Group share	1,453	1,345
Carrying amount of investments accounted for using the equity method	1,453	1,345
Revenue - 100%	2,464	3,203	3,866
Profit/(loss) from Continuing operations - 100%	629	1,168	1,613
Share of operating profit/(loss) of equity accounted investments	212	394	544
Profit/(loss) from equity accounted investments, related impairments and expenses	212	394	544
Comprehensive income/(loss) - 100%	629	1,168	1,613
Share of comprehensive income/(loss) - Group share in equity accounted investments	212	394	544
Dividends received from equity accounted investments	105	361	496
Carbones del Cerrejon LLC [member]
Disclosure of significant investments in associates and joint ventures [line items]
Current assets	712	845
Non-current assets	2,462	2,664
Current liabilities	(170)	(344)
Non-current liabilities	(854)	(801)
Net assets/(liabilities) - 100%	2,150	2,364
Net assets/(liabilities) - Group share	717	788
Adjustments to net assets related to accounting policy adjustments	59	65
Carrying amount of investments accounted for using the equity method	776	853
Revenue - 100%	1,091	2,094	2,453
Profit/(loss) from Continuing operations - 100%	(182)	309	576
Share of operating profit/(loss) of equity accounted investments	(68)	103	192
Impairment of the carrying value of the investment in Samarco	0
Profit/(loss) from equity accounted investments, related impairments and expenses	(68)	103	192
Comprehensive income/(loss) - 100%	(182)	309	576
Share of comprehensive income/(loss) - Group share in equity accounted investments	(68)	103	192
Dividends received from equity accounted investments	9	134	181
Individually immaterial, associates [member]
Disclosure of significant investments in associates and joint ventures [line items]
Carrying amount of investments accounted for using the equity method	356	371
Profit/(loss) from equity accounted investments, related impairments and expenses	(148)	(98)	(80)
Share of comprehensive income/(loss) - Group share in equity accounted investments	(148)	(98)	(80)
Dividends received from equity accounted investments	12	15	16
Samarco Mineracao S.A. [member]
Disclosure of significant investments in associates and joint ventures [line items]
Current assets	49	290
Non-current assets	3,601	6,103
Current liabilities	(7,961)	(6,704)
Non-current liabilities	(5,447)	(5,830)
Net assets/(liabilities) - 100%	(9,758)	(6,141)
Net assets/(liabilities) - Group share	(4,879)	(3,071)
Adjustments to net assets related to accounting policy adjustments	256	366
Investment in Samarco	405	310
Impairment of the carrying value of the investment in Samarco	(930)	(835)
Additional share of Samarco losses	3,341	2,835
Unrecognised losses	1,807	395
Revenue - 100%	26	24	30
Profit/(loss) from Continuing operations - 100%	(3,617)	(2,166)	(1,558)
Share of operating profit/(loss) of equity accounted investments	(1,918)	(1,075)	(823)
Impairment of the carrying value of the investment in Samarco	(95)	(96)	(80)
Additional share of Samarco losses	93	108	117
Unrecognised losses	1,412	118	277
Profit/(loss) from equity accounted investments, related impairments and expenses	(508)	(945)	(509)
Comprehensive income/(loss) - 100%	(3,617)	(2,166)	(1,558)
Share of comprehensive income/(loss) - Group share in equity accounted investments	(508)	(945)	(509)
Investments accounted for using equity method [member]
Disclosure of significant investments in associates and joint ventures [line items]
Carrying amount of investments accounted for using the equity method	2,585	2,569
Profit/(loss) from equity accounted investments, related impairments and expenses	(512)	(546)	147
Share of comprehensive income/(loss) - Group share in equity accounted investments	(512)	(546)	147
Dividends received from equity accounted investments	$ 126	$ 510	$ 693

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Adjustments to the group share of the net assets of joint ventures and associates made related to reflect difference in accounting policy between the parent and its investment.

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Disclosure of significant investments in associates and joint ventures.

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Local GAAP comprehensive income.

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Local GAAP current assets.

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Local GAAP current liabilities.

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Local GAAP net assets (liabilities).

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Local GAAP profit (loss) from continuing operations.

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Local GAAP revenue.

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Share of net assets (liabilities) in joint ventures and associates.

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The entity's share of profit (loss) from associates and joint ventures accounted for using the equity method and related impairments and expenses.

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Share of loss (profit) of joint ventures recognized from previous period.

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Unrecognised losses of joint ventures.

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The cash inflow representing dividends received from investments that are accounted for using the equity method, classified as investing activities. [Refer: Investments accounted for using equity method; Dividends received]

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The amount recognised as a reduction of the carrying amount of an asset or cash-generating unit to its recoverable amount. [Refer: Carrying amount [member]]

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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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The amount of investments in joint ventures in an entity's separate financial statements. [Refer: Joint ventures [member]]

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The entity's share of the profit (loss) from continuing operations of associates and joint ventures accounted for using the equity method. [Refer: Associates [member]; Continuing operations [member]; Investments accounted for using equity method; Joint ventures [member]; Profit (loss) from continuing operations]

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The entity's share of the total comprehensive income of associates and joint ventures accounted for using the equity method. [Refer: Associates [member]; Joint ventures [member]; Investments accounted for using equity method]

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The amount of the unrecognised share of joint ventures' losses if the entity has stopped recognising its share of losses when applying the equity method. [Refer: Joint ventures [member]]

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