XML 312 R109.htm IDEA: XBRL DOCUMENT v3.10.0.1
Operating segments - Summary of underlying earnings within the reportable segments (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Disclosure of operating segments [Line Items]      
Underlying earnings $ 8,808 $ 8,627 $ 5,100
– attributable to owners of Rio Tinto (net earnings) 13,638 8,762 4,617
Items excluded from underlying earnings 4,830 135 (483)
Reportable segments [Member]      
Disclosure of operating segments [Line Items]      
Underlying earnings 9,825 9,642 6,064
Reportable segments [Member] | Iron Ore [Member]      
Disclosure of operating segments [Line Items]      
Underlying earnings 6,514 6,692 4,611
Reportable segments [Member] | Aluminium [Member]      
Disclosure of operating segments [Line Items]      
Underlying earnings 1,347 1,583 947
Reportable segments [Member] | Copper & Diamonds [member]      
Disclosure of operating segments [Line Items]      
Underlying earnings 1,054 263 (18)
Reportable segments [Member] | Energy & Minerals [Member]      
Disclosure of operating segments [Line Items]      
Underlying earnings 1,012 1,242 612
Reportable segments [Member] | Other operations [Member]      
Disclosure of operating segments [Line Items]      
Underlying earnings (102) (138) (88)
Central Pension Costs, Share-Based Payments & Insurance [Member]      
Disclosure of operating segments [Line Items]      
– attributable to owners of Rio Tinto (net earnings) (90) (48) (24)
Restructuring, Project and One-Off Costs [Member]      
Disclosure of operating segments [Line Items]      
– attributable to owners of Rio Tinto (net earnings) (190) (124) (9)
Exploration and evaluation not attributed to product groups [Member]      
Disclosure of operating segments [Line Items]      
– attributable to owners of Rio Tinto (net earnings) (193) (178) (147)
Central Costs [Member]      
Disclosure of operating segments [Line Items]      
– attributable to owners of Rio Tinto (net earnings) (410) (311) (208)
Finance costs [Member]      
Disclosure of operating segments [Line Items]      
– attributable to owners of Rio Tinto (net earnings) (134) (354) (576)
Underlying earnings [member]      
Disclosure of operating segments [Line Items]      
– attributable to owners of Rio Tinto (net earnings) $ 8,808 $ 8,627 $ 5,100