XML 203 R100.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Principal accounting policies - Additional information (Detail)
$ in Millions
 12 Months Ended
Dec. 31, 2019
USD ($)
Operation
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Disclosure of initial application of standards or interpretations [Line Items]      
Trade payables $ 2,855 $ 3,180  
Onerous contracts provision $ 284    
Number of operations | Operation 13    
Environmental Loss Contingency, Liability, Period Increase (Decrease) $ 444    
Operations in closure, monitoring and remediation, cost estimation period 30 years    
Decreasing provision $ 800    
Provisions $ 15,103 13,608 $ 14,642
Provision for carrying value close-down, restoration and environmental   9,975  
Risk free rate decrease 0.50%    
Risk free interest rate on provisions 2.00%    
Intragroup loans $ 14,000    
Non-cancellable operating lease commitments not expected to be charged against EBITDA $ 2,000    
Bottom of range [member]      
Disclosure of initial application of standards or interpretations [Line Items]      
Risk free interest rate on provisions 0.50%    
Top of range [member]      
Disclosure of initial application of standards or interpretations [Line Items]      
Provisions $ 979    
Close down and restoration/ environmental [member]      
Disclosure of initial application of standards or interpretations [Line Items]      
Provisions 11,090 9,975  
Trade Payables Subject To Early Settlement Election [Member]      
Disclosure of initial application of standards or interpretations [Line Items]      
Trade payables 573 $ 632  
Escondida Joint Venture [Member]      
Disclosure of initial application of standards or interpretations [Line Items]      
Decrease in investment in Escondida Joint Venture $ 138    
Rio Tinto Kennecott [Member]      
Disclosure of initial application of standards or interpretations [Line Items]      
Operations with remaining lives 10 years    
Environmental loss contingencies, gross $ 700