Condensed Consolidated Statements of Earnings (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Net sales	$ 1,578.1	$ 1,674.0
Cost of goods sold	1,448.5	1,437.3
Gross margin	129.6	236.7
Selling, general and administrative expenses	80.9	89.8
Other operating expense	18.6	(16.5)
Operating earnings	30.1	163.4
Interest expense, net	(25.8)	(26.1)
Foreign currency transaction gain (loss)	8.9	87.8
Other income (expense)	(4.5)	0.6
Earnings from consolidated companies before income taxes	8.7	225.7
Provision for (benefit from) income taxes	9.7	(28.7)
Earnings from consolidated companies	(1.0)	254.4
Equity in net earnings (loss) of nonconsolidated companies	(0.1)	2.5
Net earnings including noncontrolling interests	(1.1)	256.9
Less: Net earnings attributable to noncontrolling interests	(0.2)	0.1
Net earnings attributable to Mosaic	$ (0.9)	$ 256.8
Basic net earnings per share attributable to Mosaic	$ 0.00	$ 0.73
Basic weighted average number of shares outstanding	350.5	351.3
Diluted net earnings per share attributable to Mosaic	$ 0.00	$ 0.73
Diluted weighted average number of shares outstanding	350.5	353.2