XML 420 R142.htm IDEA: XBRL DOCUMENT v3.19.1
Goodwill - Additional Information (Detail)
oz in Millions, R in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2018
USD ($)
$ / oz
R / kg
oz
Dec. 31, 2018
ZAR (R)
$ / oz
R / kg
oz
Dec. 31, 2017
USD ($)
$ / oz
R / kg
oz
Dec. 31, 2017
ZAR (R)
$ / oz
R / kg
oz
Dec. 31, 2016
USD ($)
Dec. 31, 2020
R / kg
Dec. 31, 2019
R / kg
Disclosure of information about Goodwill [line items]              
Impairment | $ $ 71.7   $ 277.8   $ 0.0    
Annual life of mine 12 years 12 years          
Nominal discount rate 13.50% 13.50% 13.50% 13.50%      
Resource ounces | oz 24.5 24.5 29.0 29.0      
Rand [member]              
Disclosure of information about Goodwill [line items]              
Nominal discount rate 13.50% 13.50% 13.50% 13.50%      
Fair value of gold per resource ounce 17 17 17 17      
South Deep Mine [member]              
Disclosure of information about Goodwill [line items]              
Long-term gold price | R / kg 525,000 525,000       550,000 525,000
Nominal discount rate 13.50% 13.50%          
Fair value of gold per resource ounce 17 17          
Within one year [member] | Rand [member]              
Disclosure of information about Goodwill [line items]              
Long-term gold price | R / kg 525,000 525,000          
Within one year [member] | US Dollars [member]              
Disclosure of information about Goodwill [line items]              
Long-term gold price 1,200 1,200          
Later than one year [member] | Rand [member]              
Disclosure of information about Goodwill [line items]              
Long-term gold price | R / kg 550,000 550,000 525,000 525,000      
Annual life of mine 75 years 75 years 78 years 78 years      
Later than one year [member] | US Dollars [member]              
Disclosure of information about Goodwill [line items]              
Long-term gold price 1,300 1,300 1,300 1,300      
Annual life of mine 75 years 75 years 78 years 78 years      
Goodwill [member] | South Deep Mine [member]              
Disclosure of information about Goodwill [line items]              
Impairment $ 71.7 [1] R 963.9 $ 277.8 [1] R 3,495.0 $ 0.0 [1]    
[1] For the year ended 31 December 2018, the Group recognised an impairment of R6,470.9 million (US$481.5 million) (2017: R3,495.0 billion (US$277.8 million) and 2016: Rnil (US$nil)) in respect of the South Deep cash-generating unit due to the deferral of production.