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Impairment charges - Additional information (Detail) - USD ($) | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Pre-tax impairment charge | $ 134,000,000 |  |
Deferred tax assets | 3,137,000,000 | $ 3,395,000,000 |
Pre-tax impairment charge net of reversals | $ 132,000,000 | 796,000,000 | $ 249,000,000
Increase in discount rate | 1.90% |  |
Reduction of the copper price throughout the life of mine | $ 0.39 |  |
long term reduction in copper price | 13.00% |  |
Property, plant and equipment [member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Pre-tax impairment charge net of reversals | $ 130,000,000 | 435,000,000 | 248,000,000
Australia [Member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Deferred tax assets | 796,000,000 | 1,055,000,000 |
Canada [Member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Deferred tax assets | 545,000,000 | 546,000,000 |
Mongolia [Member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Deferred tax assets | 703,000,000 | 631,000,000 |
Mongolia [Member] | Copper & Diamonds [member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Recoverable amount of asset or cash-generating unit | 1,100,000,000 | 1,300,000,000 |
Pre-tax impairment charge net of reversals | $ 0 |  |
Net present value of post tax cash flows discounted percentage | 8.00% |  |
Carrying value from cash generating unit | $ 3,100,000,000 |  |
Assets and liabilities classified as held for sale [member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Deferred tax assets | 66,000,000 | 49,000,000 |
ISAL Smelter [member] | Assets and liabilities classified as held for sale [member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Business acquisition binding offer amount | $ 345,000,000 |  |
ISAL Smelter [member] | Assets and liabilities classified as held for sale [member] | Aluminerie Alouette Inc | Netherlands [Member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Percentage of ownership interest to be sold | 53.30% |  |
ISAL Smelter [member] | Assets and liabilities classified as held for sale [member] | Alufluor Ab | Sweden [Member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Percentage of ownership interest to be sold | 50.00% |  |
Rossing [member] | Energy & Minerals [Member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Pre-tax impairment charge net of reversals | $ 9,000,000 | 267,000,000 |
Rossing [member] | Namibia [Member] | Energy & Minerals [Member] | Property, plant and equipment [member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Pre-tax impairment charge |  | 267,000,000 |
Rossing [member] | Namibia, Dollars | Energy & Minerals [Member] | Property, plant and equipment [member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Pre-tax impairment charge | $ 9,000,000 |  |
Argyle Diamond Mine [member] | Copper & Diamonds [member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Pre-tax impairment charge net of reversals |  | 172,000,000 | 241,000,000
Argyle Diamond Mine [member] | Australia [Member] | Copper & Diamonds [member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Pre-tax impairment charge |  | 172,000,000 |
Description of impairment trigger assessment | In 2016, our annual impairment trigger assessment at the Argyle CGU identified the impact of lower production volumes compared with forecast and lower prices achieved for bulk diamonds as impairment indicators. We calculated a recoverable amount for Argyle of US$191 million, resulting in a pre-tax impairment charge of US$241 million to property, plant and equipment and intangible assets. In 2017, our annual impairment trigger assessment at the Argyle CGU identified 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, we 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, which will be recovered by other business units in the same tax group. |  |
Deferred tax assets |  | 34,000,000 |
Recoverable amount of asset or cash-generating unit |  |  | 191,000,000
Argyle Diamond Mine [member] | Australia [Member] | Copper & Diamonds [member] | Property, plant and equipment [member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Pre-tax impairment charge |  |  | $ 241,000,000
Roughrider [member] | Energy & Minerals [Member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Pre-tax impairment charge net of reversals |  | 357,000,000 |
Roughrider [member] | Canada [Member] | Energy & Minerals [Member] |  |  |
Disclosure Of Impairment Loss And Reversal Of Impairment Loss [Line Items] |  |  |
Pre-tax impairment charge net of reversals |  | $ 357,000,000 |

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