| 
           Segment Information (Tables)
  
         | 
        12 Months Ended | 
      
      
        | 
           Dec. 31, 2014 
         | 
      
      
        | Segment Reporting [Abstract] | 
         
 | 
      
      
        | Reconciliation of Revenue from Segments to Consolidated | 
        
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
 Year Ended
 December 31, | 
   | 
  
 
 |   | 
    | 
 2014 | 
   | 
    | 
 2013 | 
   | 
    | 
 2012 | 
   | 
  
 
 |   | 
    | 
 (In
 millions) | 
   | 
  
 
 | 
  Net
 Sales: 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
 | 
  Primary Reporting
 Segment: 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
 | 
  United States(4) 
  | 
    | 
 $ | 
 905.1 | 
    | 
    | 
 $ | 
 886.9 | 
    | 
    | 
 $ | 
 816.9 | 
    | 
  
 
 | 
  Mexico 
  | 
    | 
   | 
 567.9 | 
    | 
    | 
   | 
 562.4 | 
    | 
    | 
   | 
 496.1 | 
    | 
  
 
 | 
  South Korea 
  | 
    | 
   | 
 416.0 | 
    | 
    | 
   | 
 433.7 | 
    | 
    | 
   | 
 421.4 | 
    | 
  
 
 | 
  Others(4) 
  | 
    | 
   | 
 2,405.3 | 
    | 
    | 
   | 
 2,470.7 | 
    | 
    | 
   | 
 2,059.4 | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
 
 | 
  Total Primary Reporting
 Segment 
  | 
    | 
   | 
 4,294.3 | 
    | 
    | 
   | 
 4,353.7 | 
    | 
    | 
   | 
 3,793.8 | 
    | 
  
 
 | 
  China 
  | 
    | 
   | 
 664.3 | 
    | 
    | 
   | 
 471.6 | 
    | 
    | 
   | 
 278.5 | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
 
 | 
  Total Net Sales 
  | 
    | 
 $ | 
 4,958.6 | 
    | 
    | 
 $ | 
 4,825.3 | 
    | 
    | 
 $ | 
 4,072.3 | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
  
  
 | 
      
      
        | Reconciliation of Operating Profit (Loss) from Segments to Consolidated | 
        
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
 Year Ended
 December 31, | 
   | 
  
 
 |   | 
    | 
 2014 | 
   | 
    | 
 2013 | 
   | 
    | 
 2012 | 
   | 
  
 
 |   | 
    | 
 (In
 millions) | 
   | 
  
 
 | 
  Contribution
 Margin(1): 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
 | 
  Primary Reporting
 Segment: 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
 | 
  United States(4) 
  | 
    | 
 $ | 
 373.1 | 
    | 
    | 
 $ | 
 367.9 | 
    | 
    | 
 $ | 
 359.5 | 
    | 
  
 
 | 
  Mexico 
  | 
    | 
   | 
 251.7 | 
    | 
    | 
   | 
 251.7 | 
    | 
    | 
   | 
 205.6 | 
    | 
  
 
 | 
  South Korea 
  | 
    | 
   | 
 227.6 | 
    | 
    | 
   | 
 214.3 | 
    | 
    | 
   | 
 199.4 | 
    | 
  
 
 | 
  Others(4) 
  | 
    | 
   | 
 1,055.6 | 
    | 
    | 
   | 
 1,107.8 | 
    | 
    | 
   | 
 906.5 | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
 
 | 
  Total Primary Reporting
 Segment 
  | 
    | 
   | 
 1,908.0 | 
    | 
    | 
   | 
 1,941.7 | 
    | 
    | 
   | 
 1,671.0 | 
    | 
  
 
 | 
  China(2) 
  | 
    | 
   | 
 596.6 | 
    | 
    | 
   | 
 422.7 | 
    | 
    | 
   | 
 250.1 | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
 
 | 
  Total Contribution
 Margin 
  | 
    | 
 $ | 
 2,504.6 | 
    | 
    | 
 $ | 
 2,364.4 | 
    | 
    | 
 $ | 
 1,921.1 | 
    | 
  
 
 | 
  Selling, general and
 administrative expense (2) 
  | 
    | 
   | 
 1,991.1 | 
    | 
    | 
   | 
 1,629.1 | 
    | 
    | 
   | 
 1,259.7 | 
    | 
  
 
 | 
  Interest expense 
  | 
    | 
   | 
 91.7 | 
    | 
    | 
   | 
 26.6 | 
    | 
    | 
   | 
 16.7 | 
    | 
  
 
 | 
  Interest income 
  | 
    | 
   | 
 12.5 | 
    | 
    | 
   | 
 8.0 | 
    | 
    | 
   | 
 6.2 | 
    | 
  
 
 | 
  Other expense,
 net 
  | 
    | 
   | 
 13.0 | 
    | 
    | 
   | 
 — | 
    | 
    | 
   | 
 — | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
 
 | 
  Income before income
 taxes 
  | 
    | 
   | 
 421.0 | 
    | 
    | 
   | 
 716.7 | 
    | 
    | 
   | 
 650.9 | 
    | 
  
 
 | 
  Income taxes 
  | 
    | 
   | 
 112.6 | 
    | 
    | 
   | 
 189.2 | 
    | 
    | 
   | 
 186.9 | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
 
 | 
  Net Income 
  | 
    | 
 $ | 
 308.7 | 
    | 
    | 
 $ | 
 527.5 | 
    | 
    | 
 $ | 
 464.0 | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
  
 
   
 
 
 | (1) | 
 Contribution margin
 consists of net sales less cost of sales and royalty
 overrides. | 
  
  
 
   
 
 
 | (2) | 
 Service fees to China
 independent service providers totaling $312.7 million, $215.6
 million, and $123.5 million for the years ended December 31,
 2014, 2013, and 2012, respectively, are included in selling,
 general and administrative expenses while Member compensation for
 all other countries is included in contribution margin. | 
  
  
 
   
 
 
 | (4) | 
 Net sales and contribution
 margin for 2013 within the Primary Reporting Segment information
 has been revised to correct a misclassification. As a result,
 United States net sales and contribution margin have been increased
 by $6.0 million and $2.7 million, respectively, while Others net
 sales and contribution margin have been decreased by similar
 amounts. | 
  
  
  
 | 
      
      
        | Capital Expenditures | 
        
 
 | Year Ended
 December 31, | 
   | 
  
 
 |   | 
    | 
 2014 | 
   | 
    | 
 2013 | 
   | 
    | 
 2012 | 
   | 
  
 
 |   | 
    | 
 (In
 millions) | 
   | 
  
 
 | 
  
 Capital Expenditures: 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
 | 
  
 United States 
  | 
    | 
 $ | 
 119.7 | 
    | 
    | 
 $ | 
 121.3 | 
    | 
    | 
 $ | 
 81.6 | 
    | 
  
 
 | 
  
 Mexico 
  | 
    | 
   | 
 3.8 | 
    | 
    | 
   | 
 2.4 | 
    | 
    | 
   | 
 2.8 | 
    | 
  
 
 | 
  
 South Korea 
  | 
    | 
   | 
 0.2 | 
    | 
    | 
   | 
 1.8 | 
    | 
    | 
   | 
 4.1 | 
    | 
  
 
 | 
  
 China 
  | 
    | 
   | 
 13.0 | 
    | 
    | 
   | 
 12.6 | 
    | 
    | 
   | 
 15.4 | 
    | 
  
 
 | 
  
 Others 
  | 
    | 
   | 
 20.0 | 
    | 
    | 
   | 
 24.4 | 
    | 
    | 
   | 
 18.9 | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
 
 | 
  
 Total Capital Expenditures 
  | 
    | 
 $ | 
 156.7 | 
    | 
    | 
 $ | 
 162.5 | 
    | 
    | 
 $ | 
 122.8 | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
  
 | 
      
      
        | Schedule of Entity-Wide Information, Revenue from External Customers by Products and Services | 
        
 
 
 | Year Ended
 December 31, | 
   | 
  
 
 |   | 
    | 
 2014 | 
   | 
    | 
 2013 | 
   | 
    | 
 2012 | 
   | 
  
 
 |   | 
    | 
 (In
 millions) | 
   | 
  
 
 | 
  Net sales by product
 line: 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
 | 
  Weight
 Management 
  | 
    | 
 $ | 
 3,177.0 | 
    | 
    | 
 $ | 
 3,063.7 | 
    | 
    | 
 $ | 
 2,554.9 | 
    | 
  
 
 | 
  Targeted
 Nutrition 
  | 
    | 
   | 
 1,108.5 | 
    | 
    | 
   | 
 1,109.9 | 
    | 
    | 
   | 
 944.8 | 
    | 
  
 
 | 
  Energy, Sports &
 Fitness 
  | 
    | 
   | 
 260.6 | 
    | 
    | 
   | 
 254.5 | 
    | 
    | 
   | 
 209.4 | 
    | 
  
 
 | 
  Outer
 Nutrition 
  | 
    | 
   | 
 178.9 | 
    | 
    | 
   | 
 157.2 | 
    | 
    | 
   | 
 146.3 | 
    | 
  
 
 | 
  Literature, Promotional
 and Other(3) 
  | 
    | 
   | 
 233.6 | 
    | 
    | 
   | 
 240.0 | 
    | 
    | 
   | 
 216.9 | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
 
 | 
  Total Net
 Sales 
  | 
    | 
 $ | 
 4,958.6 | 
    | 
    | 
 $ | 
 4,825.3 | 
    | 
    | 
 $ | 
 4,072.3 | 
    | 
  
  
   
 
 
 | (3) | 
 Product buybacks and returns in all
 product categories are included in the literature, promotional and
 other category. | 
  
  
  
 | 
      
      
        | Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area | 
        
 
 | 
  
 Net sales by geographic region: 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
 | 
  
 North America 
  | 
    | 
 $ | 
 0 | 
    | 
    | 
 $ | 
 908.0 | 
    | 
    | 
 $ | 
 841.2 | 
    | 
  
 
 | 
  
 Mexico 
  | 
    | 
   | 
 0 | 
    | 
    | 
   | 
 562.4 | 
    | 
    | 
   | 
 496.1 | 
    | 
  
 
 | 
  
 South & Central America 
  | 
    | 
   | 
 0 | 
    | 
    | 
   | 
 973.5 | 
    | 
    | 
   | 
 688.8 | 
    | 
  
 
 | 
  
 EMEA 
  | 
    | 
   | 
 0 | 
    | 
    | 
   | 
 735.2 | 
    | 
    | 
   | 
 627.8 | 
    | 
  
 
 | 
  
 Asia Pacific 
  | 
    | 
   | 
 0 | 
    | 
    | 
   | 
 1,174.6 | 
    | 
    | 
   | 
 1,139.9 | 
    | 
  
 
 | 
  
 China 
  | 
    | 
   | 
 0 | 
    | 
    | 
   | 
 471.6 | 
    | 
    | 
   | 
 278.5 | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
 
 | 
  
 Total Net Sales 
  | 
    | 
 $ | 
 0 | 
    | 
    | 
 $ | 
 4,825.3 | 
    | 
    | 
 $ | 
 4,072.3 | 
    | 
  
 
  | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
    | 
 
    
  | 
 
    
  | 
   | 
  
 
 
 |