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Risk Management Activities - Additional Information (Detail)
l in Millions, R in Millions
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Nov. 30, 2017
USD ($)
R / kg
Ounce_of_Gold
$ / Tonne
T
Jul. 31, 2017
$ / Tonne
T
Jun. 30, 2017
USD ($)
$ / Barrel
ppm
l
$ / Metric_tonne
May 31, 2017
USD ($)
$ / Barrel
ppm
l
$ / Metric_tonne
Sep. 30, 2016
Exchange_Rate
Dec. 31, 2017
USD ($)
$ / oz
oz
Dec. 31, 2016
USD ($)
Exchange_Rate
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2016
ZAR (R)
Feb. 25, 2016
USD ($)
Disclosure Of Financial Risk Management [Line Items]                      
Borrowings           $ 1,781,500,000 $ 1,692,900,000 $ 1,781,500,000 $ 1,692,900,000    
Forward exchange contracts [member] | South deep [member] | Hedges of net investment in foreign operations [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Average forward price | Exchange_Rate             16.8273        
Cash settled swap transaction contracts [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Mark-to-market value of the hedge           5,100,000   5,100,000      
Trade and other receivable [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
VAT, prepayments and diesel rebates           135,400,000 $ 101,700,000 135,400,000 101,700,000    
Trade and other receivable [member] | Financial instruments not Credit - impaired [member] | Banking Institutions [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Past due but not impaired               0 0    
Receivables [member] | Financial instruments credit - impaired [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Receivables considered impaired           100,000 200,000 $ 100,000 200,000    
Counter party exposure [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Percentage of maximum investment in financial institutions' equity               2.50%      
Currency risk [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Exposure to risk relating to financial instruments           $ 0 0 $ 0 0    
Currency risk [member] | Forward exchange contracts [member] | South deep [member] | Hedges of net investment in foreign operations [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Risk hedging delivery amount                     $ 69,800,000
Average forward price | Exchange_Rate         13.8010            
Risk hedge resulting profit                 14,400,000 R 211.2  
Commodity price risk [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Average forward price | $ / oz           1,719.9          
Risk hedge resulting profit               15,300,000      
Number of ounces committed under contract | oz           295,000          
Commodity price risk [member] | South deep [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Number of ounces committed under contract | Ounce_of_Gold 63,996                    
Mark-to-market value of the hedge $ 10,900,000                    
Commodity price risk [member] | Cash settled swap transaction contracts [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Volume of diesel hedged | l     77.5 77.5              
Average swap price | $ / Barrel     61.15 61.15              
Risk hedging number | ppm     10 10              
Commodity price risk [member] | Peru [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Mark-to-market value of the hedge $ (3,300,000)                    
Number of tonnes committed under contract | T 29,400 8,250                  
Commodity price risk [member] | Ghana [member] | Cash settled swap transaction contracts [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Mark-to-market value of the hedge     $ 9,000,000 $ 9,000,000              
Volume of diesel hedged | l     125.8 125.8              
Average swap price | $ / Metric_tonne     457.2 457.2              
Average swap price | $ / Barrel     61.4 61.4              
Commodity price risk [member] | Floor rate [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Strike price of gold | $ / oz           1,695.9          
Commodity price risk [member] | Floor rate [member] | South deep [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Strike price of gold | R / kg 600,000                    
Commodity price risk [member] | Floor rate [member] | Peru [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Strike price of copper | $ / Tonne 6,600 5,867                  
Commodity price risk [member] | Interest rate caps [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Strike price of gold | $ / oz           1,754.2          
Commodity price risk [member] | Interest rate caps [member] | South deep [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Strike price of gold | R / kg 665,621                    
Commodity price risk [member] | Interest rate caps [member] | Peru [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Strike price of copper | $ / Tonne 7,431 6,300                  
Commodity price risk [member] | Brent crude [member] | Cash settled swap transaction contracts [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Benchmark price per barrel at time transaction | $ / Barrel     49.92 49.92              
Commodity price risk [member] | Brent crude [member] | Ghana [member] | Cash settled swap transaction contracts [member] | Fair value hedges [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Benchmark price per barrel at time transaction | $ / Barrel     49.8 49.8              
Change in London Interbank Offered Rate [member] | Interest Bearing Borrowings [Member] | Floating Interest Rate [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Borrowings exposed to interest rate fluctuations           $ 508,500,000 785,500,000 508,500,000 785,500,000    
Johannesburg Interbank Average Rate and Prime Interest Rates [member] | Interest Bearing Borrowings [Member] | Floating Interest Rate [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Borrowings exposed to interest rate fluctuations           79,500,000 0 79,500,000 0    
Change in South African Prime Interest Rate [Member] | Interest Bearing Borrowings [Member] | Floating Interest Rate [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Borrowings exposed to interest rate fluctuations           114,100,000 61,000,000 114,100,000 61,000,000    
Change in Bank Bill Swap Bid Rate [member] | Interest Bearing Borrowings [Member] | Floating Interest Rate [member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Borrowings exposed to interest rate fluctuations           231,500,000 0 231,500,000 0    
Sensitivity to interest rates [member] | Interest Bearing Borrowings [Member]                      
Disclosure Of Financial Risk Management [Line Items]                      
Borrowings exposed to interest rate fluctuations           $ 933,600,000 $ 846,500,000 $ 933,600,000 $ 846,500,000