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Impairment charges and reversals - Additional information (Detail) - USD ($)
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge net of reversals $ 796,000,000 $ 249,000,000 $ 2,791,000,000
Impairment charges, Non-controlling interests 174,000,000    
Deferred tax assets 3,395,000,000 3,728,000,000  
Goodwill [Member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge net of reversals     116,000,000
Property, plant and equipment [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge net of reversals 435,000,000 248,000,000 652,000,000
Canada [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Deferred tax assets 546,000,000 470,000,000  
Australia [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Deferred tax assets 1,055,000,000 1,072,000,000  
United States [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Deferred tax assets 877,000,000 $ 1,239,000,000  
Energy & Minerals [Member] | Roughrider [member] | Canada [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Recoverable amount of asset or cash-generating unit 0    
Pre-tax impairment charge net of reversals $ 357,000,000    
Description of change in valuation technique used to measure fair value less costs of disposal The recoverable amount for Roughrider was determined by reference to a fair value less cost of disposal (FVLCD) model in line with the accounting policy set out in note 1(i).    
Energy & Minerals [Member] | Roughrider [member] | Canada [member] | Exploration and evaluation [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge     113,000,000
Energy & Minerals [Member] | Roughrider [member] | Canada [member] | Goodwill [Member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge     116,000,000
Energy & Minerals [Member] | Rossing [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Impairment charges, Non-controlling interests $ 83,000,000    
Energy & Minerals [Member] | Rossing [member] | Namibia, Dollars | Property, plant and equipment [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge 267,000,000    
Energy & Minerals [Member] | Simandou [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Impairment charges, Non-controlling interests 91,000,000    
Energy & Minerals [Member] | Simandou [member] | Guinea [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Impairment charges, Non-controlling interests     91,000,000
Energy & Minerals [Member] | Simandou [member] | Guinea [member] | Exploration and evaluation [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge     1,655,000,000
Energy & Minerals [Member] | Simandou [member] | Guinea [member] | Exploration and evaluation [member] | Contractual arrangements [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge     183,000,000
Energy & Minerals [Member] | Simandou [member] | Guinea [member] | Property, plant and equipment [member] | Exploration and evaluation [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge     194,000,000
Energy & Minerals [Member] | Simandou [member] | Guinea [member] | Inventories [member] | Exploration and evaluation [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge     7,000,000
Energy & Minerals [Member] | Energy Resources of Australia [member] | Australia [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Write off of deferred tax assets     123,000,000
Energy & Minerals [Member] | Energy Resources of Australia [member] | Australia [member] | Property, plant and equipment and intangible assets [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge     260,000,000
Copper & Diamonds [member] | Argyle Diamond Mine [member] | Australia [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Recoverable amount of asset or cash-generating unit 191,000,000    
Pre-tax impairment charge $ 241,000,000    
Description of impairment trigger assessment In 2016, an impairment trigger assessment at the Argyle cash-generating unit resulted in the identification of impairment indicators as a result of lower production volumes compared with forecast and lower prices achieved for bulk diamonds. The recoverable amount for Argyle was determined to be US$191 million, resulting in a pre-tax impairment charge of US$241 million to property, plant and equipment and intangible assets. In 2017, an impairment trigger assessment at the Argyle cash-generating unit resulted in the identification of impairment indicators because of lower production volumes compared with forecast, a smaller than expected contribution from productivity improvements and lower realised prices. In assessing the recoverable amount of the assets, it was determined that the property, plant and equipment, including an updated closure asset, was fully impaired resulting in a pre-tax impairment charge of US$172 million. The impairment charge resulted in the recognition of deferred tax assets of US$34 million; these will be recovered by other business units in the same tax group.    
Deferred tax assets $ 34,000,000    
Copper & Diamonds [member] | Argyle Diamond Mine [member] | Australia [member] | Property, plant and equipment [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge $ 172,000,000    
Copper & Diamonds [member] | Molybdenum Autoclave Process [member] | United States [member] | Property, plant and equipment [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge     17,000,000
Aluminium [Member] | Carbone savoie [Member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge     147,000,000
Aluminium [Member] | Other aluminium businesses [member]      
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items]      
Pre-tax impairment charge     $ 32,000,000