Acquisition (Details) (USD $)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Business combination, consideration transferred      
Payment for acquisition $ 0 $ 1,353,600,000  
Total assets acquired and liabilities assumed, net      
Goodwill 1,686,700,000   1,806,500,000
Business Acquisition, Pro Forma Information [Abstract]      
Pro forma net sales   2,300,000,000  
Pro-forma net earnings attributable to Mosaic   208,600,000  
Brazil and Paraguay Distribution Business Acquisition [Member]      
Business combination, consideration transferred      
Payment for acquisition 301,700,000    
Total assets acquired and liabilities assumed, net      
Inventory 117,000,000    
Other current assets 9,400,000    
Property, plant and equipment 95,900,000    
Goodwill 83,800,000    
Intangible assets 19,100,000    
Other assets 16,800,000    
Current liabilities (23,500,000)    
Other liabilities (16,800,000)    
Total assets acquired and liabilities assumed, net $ 301,700,000