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Goodwill - Additional Information (Detail)
oz in Millions, R in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2019
USD ($)
$ / oz
ZAR-kg
$ / per_oz
oz
Dec. 31, 2019
ZAR (R)
$ / oz
ZAR-kg
$ / per_oz
oz
Dec. 31, 2018
USD ($)
$ / oz
$ / per_oz
Dec. 31, 2018
ZAR (R)
$ / oz
$ / per_oz
Dec. 31, 2017
USD ($)
Dec. 31, 2017
ZAR (R)
Disclosure of information about Goodwill [line items]            
Impairment | $ $ 0.0   $ 71.7   $ 277.8  
Annual life of mine     12 years 12 years    
Resource ounces | oz 24.5 24.5        
Rand [member]            
Disclosure of information about Goodwill [line items]            
Nominal discount rate 14.10% 14.10% 13.50% 13.50%    
Fair value of gold per resource ounce | $ / per_oz 16 16 17.0 17.0    
Within one year [member] | Rand [member]            
Disclosure of information about Goodwill [line items]            
Long-term gold price | ZAR-kg 525,000 525,000        
Within one year [member] | US Dollars [member]            
Disclosure of information about Goodwill [line items]            
Long-term gold price | $ / oz 1,200 1,200 1,200 1,200    
Later than one year [member] | Rand [member]            
Disclosure of information about Goodwill [line items]            
Long-term gold price | ZAR-kg 550,000 550,000        
Annual life of mine 75 years 75 years        
Later than one year [member] | US Dollars [member]            
Disclosure of information about Goodwill [line items]            
Long-term gold price | $ / oz 1,300 1,300 1,300 1,300    
Annual life of mine 75 years 75 years        
Goodwill [member] | South Deep Mine [member]            
Disclosure of information about Goodwill [line items]            
Impairment $ 0.0 [1] R 0.0 $ 71.7 R 963.9 $ 277.8 [1] R 3,495,000.0
[1] For the year ended 31 December 2019, the Group recognised an impairment of Rnil (US$nil) (2018: R6,470.9 million (US$481.5 million) and 2017: R3,495.0 billion (US$277.8 million)) in respect of the South Deep cash-generating unit due to the deferral of production. Rnil (US$nil) (2018: R963.9 million (US$71.7 million) and 2017: R3,495.0 billion (US$277.8 million)) of the total impairment was firstly allocated against goodwill and the remainder of Rnil (US$nil) (2018: R5,507.0 million (US$409.8 million) and 2017: Rnil (US$nil)) against other assets. The recoverable amount was based on its FVLCOD calculated using a combination of the market and the income approach (level 3 of the fair value hierarchy).