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Goodwill - Additional Information (Detail)
oz in Millions, R in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2017
USD ($)
$ / oz
R / kg
oz
Dec. 31, 2017
ZAR (R)
$ / oz
R / kg
oz
Dec. 31, 2016
USD ($)
$ / oz
R / kg
oz
Dec. 31, 2015
USD ($)
Disclosure of information about Goodwill [Line Items]        
Impairment | $ $ 277.8   $ 0.0 $ 0.0
Annual life of mine 78 years 78 years 79 years  
Nominal discount rate 13.50% 13.50% 13.50%  
Fair value of gold per resource ounce 17.0 17.0 60.0  
Resource ounces | oz 29.0 29.0 26.0  
South Deep Mine [member]        
Disclosure of information about Goodwill [Line Items]        
Impairment $ 277.8 R 3,495.0    
Long-term gold price | R / kg 525,000 525,000    
Nominal discount rate 13.50% 13.50%    
Fair value of gold per resource ounce 17 17    
Rand [member]        
Disclosure of information about Goodwill [Line Items]        
Long-term gold price | R / kg 525,000 525,000 600,000  
Fair value of gold per resource ounce 17 17 60  
US Dollars [member]        
Disclosure of information about Goodwill [Line Items]        
Long-term gold price 1,300 1,300 1,300