XML 110 R58.htm IDEA: XBRL DOCUMENT v3.21.1
Significant Accounting Policies - Additional Information (Detail)
$ in Millions
 12 Months Ended
Dec. 31, 2020
USD ($)
Anniversaries
Dec. 31, 2019
USD ($)
Anniversaries
Dec. 31, 2018
USD ($)
Anniversaries
Disclosure of significant accounting policies [line items]      
Share-based compensation $ 29 $ 32 $ 35
Minimum equity interest for significant influence 20.00%    
Number of customers | Anniversaries 0 0 0
Revenues $ 12,970 $ 13,130 $ 13,531
Increase decrease in financing obligations connected with leases 213 274 296
Effect Of Adoption Of Accounting Standard On Retained Earnings 6    
Emission Rights [Member]      
Disclosure of significant accounting policies [line items]      
Revenues $ 0 0 0
Computer software [member]      
Disclosure of significant accounting policies [line items]      
Useful life of intangible asset 5 years    
Extraction rights [member]      
Disclosure of significant accounting policies [line items]      
Useful life of intangible asset 83 years    
Bottom of range [member]      
Disclosure of significant accounting policies [line items]      
Useful life of intangible asset 3 years    
Top of range [member]      
Disclosure of significant accounting policies [line items]      
Useful life of intangible asset 20 years    
Mobile equipment [member]      
Disclosure of significant accounting policies [line items]      
Carrying amount of assets acquired through capital lease $ 213 274 296
Additional paid-in capital [member]      
Disclosure of significant accounting policies [line items]      
Share-based compensation $ 29 $ 17 $ 34