The Mosaic Company (MOS) 10-Q 5 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Sep. 30, 2013	Nov. 01, 2013	Nov. 01, 2013
		No class common stock [Member]	Class A common stock [Member]
Document Information [Line Items]	'	'	'
Entity registrant name	'MOSAIC CO	'	'
Document type	'10-Q	'	'
Entity central index key	'0001285785	'	'
Amendment flag	'false	'	'
Entity current reporting status	'Yes	'	'
Entity voluntary filers	'No	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'Q3	'	'
Document period end date	30-Sep-13	'	'
Current fiscal year end date	'--12-31	'	'
Entity filer category	'Large Accelerated Filer	'	'
Entity well known seasoned issuer	'Yes	'	'
Entity common stock shares outstanding	'	297,220,797	128,759,772

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Earnings (Unaudited) (USD $)	3 Months Ended		4 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Condensed Consolidated Statement of Earnings (Unaudited) [Abstract]	'	'	'
Net sales	$1,908.70	$2,645.70	$2,584.30
Cost of goods sold	1,521.80	1,871.10	2,077.50
Gross margin	386.9	774.6	506.8
Selling, general and administrative expenses	94.4	114.8	120.6
Loss on write down of assets	122.8	0	122.8
Other operating expense (income)	25.6	16.1	25.5
Operating earnings	144.1	643.7	237.9
Interest income (expense), net	1.8	5.1	-1.3
Foreign currency transaction gain (loss)	-29.6	-27.3	-8.6
Other (expense) income	0.4	-0.6	0.2
Earnings from consolidated companies before income taxes	116.7	620.9	228.2
Provision for (benefit from) income taxes	-6.6	189	21.4
Earnings from consolidated companies	123.3	431.9	206.8
Equity in net earnings (loss) of nonconsolidated companies	2.5	-12.9	6
Net earnings including noncontrolling interests	125.8	419	212.8
Less: Net earnings (loss) attributable to noncontolling interests	1.4	1.6	1.8
Net earnings attributable to Mosaic	$124.40	$417.40	$211
Basic net earnings per share attributable to Mosaic	$0.29	$0.98	'
Diluted net earnings per share attributable to Mosaic	$0.29	$0.98	'
Basic weighted average number of shares outstanding	425.9	425.6	'
Diluted weighted average number of shares outstanding	427.1	426.8	'

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Statement of Income and Comprehensive Income [Abstract]	'	'
Net earnings including noncontrolling interests	$125.80	$419
Other comprehensive income (loss), net of tax	'	'
Foreign currency translation, net of tax	140.9	210.5
Net actuarial gain (loss) and prior service cost, net of tax	2.4	3.6
Unrealized gain (loss) on derivative instruments	-1	0
Other comprehensive income (loss)	142.3	214.1
Total comprehensive income	268.1	633.1
Less: Comprehensive income (loss), attributable to noncontrolling interest	1.4	1.4
Comprehensive income attributable to Mosaic	$266.70	$631.70

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheet (USD $)	Sep. 30, 2013	31-May-13
In Millions, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$3,338.60	$3,697.10
Receivables, net	478.7	1,015.70
Inventories	1,495	1,557.30
Deferred income taxes	81.2	75.7
Other current assets	897.8	534.7
Total current assets	6,291.30	6,880.50
Property, plant and equipment, net of accumulated depreciation	8,513	8,486.80
Investments in nonconsolidated companies	562.1	431.5
Goodwill	1,833.20	1,844.60
Deferred income taxes	212.5	212.7
Other assets	244.5	229.9
Total assets	17,656.60	18,086
Current liabilities:	'	'
Short-term debt	14.5	68.7
Current maturities of long-term debt	0.8	0.9
Accounts payable	611.7	763.1
Accrued liabilities	588.7	845.1
Deferred income taxes	86.6	87.1
Total current liabilities	1,302.30	1,764.90
Long-term debt, less current maturities	1,011.50	1,009.60
Deferred income taxes	960.9	961.4
Other noncurrent liabilities	830.8	907.2
Capital in excess of par value	1,507.80	1,491.30
Retained earnings	11,707.60	11,603.40
Accumulated other comprehensive income	312.9	326.4
Total Mosaic stockholders equity	13,532.60	13,425.40
Noncontrolling interests	18.5	17.5
Total equity	13,551.10	13,442.90
Total liabilities and equity	17,656.60	18,086
Class A common stock [Member]	'	'
Current liabilities:	'	'
Common stock, value	1.3	1.3
No class common stock [Member]	'	'
Current liabilities:	'	'
Common stock, value	$3	$3

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) (USD $)	Sep. 30, 2013	31-May-13
In Millions, except Share data, unless otherwise specified
Statement Of Financial Position Parenthetical [Line Items]	'	'
Accumulated depreciation	$3,673.10	$3,284.20
Preferred stock, par value	$0.01	$0.01
Preferred stock, authorized	15,000,000	15,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Class A common stock [Member]	'	'
Statement Of Financial Position Parenthetical [Line Items]	'	'
Common stock, par value	$0.01	$0.01
Common stock, authorized	254,300,000	254,300,000
Common stock, issued	150,059,772	150,059,772
Common stock, outstanding	128,759,772	128,759,772
Class B common stock [Member]	'	'
Statement Of Financial Position Parenthetical [Line Items]	'	'
Common stock, par value	$0.01	$0.01
Common stock, authorized	87,008,602	87,008,602
Common stock, issued	0	0
Common stock, outstanding	0	0
No class common stock [Member]	'	'
Statement Of Financial Position Parenthetical [Line Items]	'	'
Common stock, par value	$0.01	$0.01
Common stock, authorized	1,000,000,000	1,000,000,000
Common stock, issued	309,245,292	309,095,779
Common stock, outstanding	297,206,830	297,057,317

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash Flows from Operating Activities	'	'
Net earnings including noncontrolling interests	$125.80	$419
Depreciation, depletion and amortization	166.1	140.6
Deferred income taxes	0	0.3
Equity in net loss of nonconsolidated companies, net of dividends	7	31
Accretion expense for asset retirement obligations	9.9	7.1
Share-based compensation expense	14.1	17.7
Loss on write down of assets	122.8	0
Unrealized loss (gain) on derivatives	-40.7	-52.5
Other	-3.1	-1.4
Receivables, net	131.7	-81
Inventories	-2.5	-213.1
Other current and noncurrent assets	-167.8	29.6
Accounts payable	-104.1	128.3
Accrued liabilities and income taxes	-221	-108
Other noncurrent liabilities	-83.2	26.2
Net cash provided by (used in) operating activities	-45	343.8
Cash Flows from Investing Activities	'	'
Capital expenditures	-332.5	-384.6
Restricted cash	0	7.8
Investments in nonconsolidated companies	-134.5	0
Other	1.3	1.3
Net cash (used in) investing activities	-465.7	-375.5
Cash Flows from Financing Activities	'	'
Payments of short-term debt	-42.9	-5.4
Proceeds from issuance of short-term debt	57.2	10.3
Payments of long-term debt	-0.7	-0.2
Proceeds from issuance of long-term debt	2.7	-0.1
Proceeds from stock options exercised	0.5	-1.7
Dividends	-106.8	-106.6
Other	0.5	0.8
Net cash (used in) financing activities	-89.5	-102.9
Effect of exchange rate changes on cash	23.3	26.9
Net change in cash and cash equivalents	-576.9	-107.7
Cash and cash equivalents - beginning of period	3,915.50	3,656.20
Cash and cash equivalents - end of period	3,338.60	3,548.50
Supplemental Disclosure of Cash Flow Information:	'	'
Interest (net of amount capitalized)	0	0
Income taxes (net of refunds)	$0	$130.40

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flow Parenthetical (USD $)	3 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Statement Of Cash Flows Abstract	'	'
Capitalized interest costs	$12.10	$12.80

Condensed_Consolidated_Stateme4

Condensed Consolidated Statements of Shareholders Equity (Unaudited) (USD $)	Total	Common Stock [Member]	Capital in Excess of Par Value [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
In Millions, except Share data
Beginning balance at May. 31, 2013	$13,442.90	$4.30	$1,491.30	$11,603.40	$326.40	$17.50
Common stock shares outstanding, beginning balance at May. 31, 2013	'	425,800,000	'	'	'	'
Total comprehensive income	198.7	'	'	211	-13.5	1.2
Stock option exercises	0.7	'	0.7	'	'	'
Stock option exercises, shares	'	200,000	'	'	'	'
Amortization of stock based compensation	18.8	'	18.8	'	'	'
Dividends	-106.8	'	'	-106.8	'	'
Dividends for noncontrolling interests	-0.2	'	'	'	'	-0.2
Tax shortfall related to share based compensation	-3	'	-3	'	'	'
Ending balance at Sep. 30, 2013	$13,551.10	$4.30	$1,507.80	$11,707.60	$312.90	$18.50
Common stock shares outstanding, ending balance at Sep. 30, 2013	'	426,000,000	'	'	'	'

Condensed_Consolidated_Stateme5

Condensed Consolidated Statements of Shareholders Equity (Unaudited) (Parentheticals) (USD $)	4 Months Ended
	Sep. 30, 2013
Condensed Consolidated Statements Of Equity Parenthetical [Abstract]	'
Dividends per share	$0.25

Organization_and_Nature_of_Bus

Organization and Nature of Business	3 Months Ended
	Sep. 30, 2013
Organization And Nature Of Business [Abstract]	'
Organization and Nature of Business	'
	1. Organization and Nature of Business
	The Mosaic Company (“Mosaic”, and, with its consolidated subsidiaries, “we”, “us”, “our”, or the “Company”) produces and markets concentrated phosphate and potash crop nutrients. We conduct our business through wholly and majority owned subsidiaries as well as businesses in which we own less than a majority or a noncontrolling interest, including consolidated variable interest entities and investments accounted for by the equity method. We are organized into the following business segments:
	Our Phosphates business segment owns and operates mines and production facilities in Florida which produce concentrated phosphate crop nutrients and phosphate-based animal feed ingredients, and processing plants in Louisiana which produce concentrated phosphate crop nutrients. Additionally, the Phosphates segment has a 35% economic interest in a joint venture that owns a phosphate rock mine (the “Miski Mayo Mine”) in Peru. On August 5, 2013 Mosaic entered into an agreement to form a joint venture (the “Northern Promise Joint Venture”), of which Mosaic will own 25%, with Saudi Arabian Mining Company (“Ma'aden”) and Saudi Basic Industries Corporation (“SABIC”) to develop a phosphate rock mine and chemical complexes that is presently contemplated to produce phosphate fertilizers, animal feed, food grade purified phosphoric acid and sodium tripolyphosphate in the Kingdom of Saudi Arabia.
	Our Phosphates segment's results also include our North American phosphate distribution activities and all of our international distribution activities as well as the results of Phosphate Chemicals Export Association, Inc. (“PhosChem”), a U.S. Webb-Pomerene Act association of phosphate producers that exports concentrated phosphate crop nutrient products around the world for us and PhosChem's other member. Our share of PhosChem's sales of dry phosphate crop nutrient products was approximately 93% for the three months ended September 30, 2013. Effective December 31, 2013, PhosChem will be dissolved.
	Our Potash business segment owns and operates potash mines and production facilities in Canada and the U.S. which produce potash-based crop nutrients, animal feed ingredients and industrial products. Potash sales include domestic and international sales. We are a member of Canpotex, Limited (“Canpotex”), an export association of Canadian potash producers through which we sell our Canadian potash outside the U.S. and Canada.
	Intersegment sales are eliminated within Corporate, Eliminations and Other. See Note 14 to our Condensed Consolidated Financial Statements in this report for segment results.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Sep. 30, 2013
Summary Of Significant Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	2. Summary of Significant Accounting Policies
	Statement Presentation and Basis of Consolidation
	The accompanying unaudited Condensed Consolidated Financial Statements of Mosaic have been prepared on the accrual basis of accounting and in accordance with the requirements of the Securities and Exchange Commission (“SEC”) for interim financial reporting. As permitted under these rules, certain footnotes and other financial information that are normally required by accounting principles generally accepted in the United States (“U.S. GAAP”) can be condensed or omitted. The Condensed Consolidated Financial Statements included in this document reflect, in the opinion of our management, all adjustments (consisting of only normal recurring adjustments) necessary for a fair statement of the results for the interim periods presented. The following notes should be read in conjunction with the accounting policies and other disclosures in the Notes to the Consolidated Financial Statements included in our Annual Report on Form 10-K filed with the SEC for the fiscal year ended May 31, 2013. Sales, expenses, cash flows, assets and liabilities can and do vary during the year as a result of seasonality and other factors. Therefore, interim results are not necessarily indicative of the results to be expected for the full fiscal year.
	The accompanying Condensed Consolidated Financial Statements include the accounts of Mosaic and its majority owned subsidiaries, as well as the accounts of certain variable interest entities (“VIEs”) for which we are the primary beneficiary. Certain investments in companies where we do not have control but have the ability to exercise significant influence are accounted for by the equity method.
	Accounting Estimates
	Preparation of the Condensed Consolidated Financial Statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of net sales and expenses during the reporting periods. The more significant estimates made by management relate to the recoverability of non-current assets, the useful lives of long-lived assets, environmental and reclamation liabilities, the costs of our employee benefit obligations for pension plans and postretirement benefits, income tax-related accounts, including the valuation allowance against deferred income tax assets, Canadian resource taxes and royalties, inventory valuation and accruals for pending legal matters. Actual results could differ from these estimates.

Recently_Issued_Accounting_Gui

Recently Issued Accounting Guidance	3 Months Ended
	Sep. 30, 2013
Recently Issued Accounting Guidance [Abstract]	'
Recently Issued Accounting Guidance	'
	3. Recently Issued Accounting Guidance
	Recently Adopted Accounting Pronouncements
	In December 2011, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2011-11, “Balance Sheet (Topic 210): Disclosures about Offsetting Assets and Liabilities” which enhances current disclosures about financial instruments and derivative instruments that are either offset on the statement of financial position or subject to an enforceable master netting arrangement or similar agreement, irrespective of whether they are offset on the statement of financial position. Entities are required to provide both net and gross information for these assets and liabilities in order to facilitate comparability between financial statements prepared on the basis of U.S. GAAP and those prepared on the basis of International Financial Reporting Standards (“IFRS”). In January 2013, the FASB issued ASU No. 2013-01, “Balance Sheet (Topic 210): Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities” to limit the scope of the new balance sheet offsetting disclosures to derivatives, repurchase agreements, and securities lending transactions to the extent that they are offset in the financial statements or subject to an enforceable master netting arrangement or similar agreement. These standards were effective for us beginning June 1, 2013 with retrospective application required. We determined that these requirements were not material to the results of operations or financial position, and, therefore, have not added disclosures otherwise required by these standards.
	In February 2013, the FASB issued ASU No. 2013-02, “Comprehensive Income (Topic 220): Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income” which requires entities to disclose additional information about changes in and significant items reclassified out of accumulated other comprehensive income. This guidance was effective for us beginning June 1, 2013. We determined that these requirements were not material to the results of operations or financial position and, therefore, have not added disclosures otherwise required by this standard.
	Pronouncements Issued But Not Yet Adopted
	In July 2013, the FASB issued ASU No. 2013-11, “Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists” which requires that an unrecognized tax benefit should be presented in the financial statements as a reduction of a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward when settlement in this manner is available under the law. This guidance is effective for us beginning January 1, 2014 and will be applied on a prospective basis to all unrecognized tax benefits that exist at the effective date. We do not expect this guidance to have a material impact on our results of operations or financial position.

Other_Financial_Statement_Data

Other Financial Statement Data	3 Months Ended
	Sep. 30, 2013
Other Financial Statement Data [Abstract]	'
Other Financial Statement Data	'
	4. Other Financial Statement Data
	The following provides additional information concerning selected balance sheet accounts:
				September 30,		May 31,
	(in millions)			2013		2013
	Other current assets
		Final price deferred(a)	$	270.2	$	137.1
		Income and other taxes receivable		289.7		267.6
		Prepaid expenses		92		98.2
		Assets held for sale(b)		232.6		-
		Other		13.3		31.8
			$	897.8	$	534.7
	Accrued liabilities
		Non-income taxes	$	28.5	$	81.1
		Payroll and employee benefits		93.7		146.6
		Asset retirement obligations		95		83.5
		Customer prepayments		126.9		243.3
		Other		244.6		290.6
			$	588.7	$	845.1
	Other noncurrent liabilities
		Asset retirement obligations	$	564.1	$	575
		Accrued pension and postretirement benefits		125.1		140.7
		Unrecognized tax benefits		7.9		45.2
		Other		133.7		146.3
			$	830.8	$	907.2
	(a)Final price deferred is product that has shipped to customers, but the price has not yet been agreed upon. This has not been included in inventory as it is not held for sale.
	(b)See further description of assets held for sale in Footnote 16.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Schedule of earnings per share	'
	5. Earnings Per Share
	The numerator for basic and diluted earnings per share (“EPS”) is net earnings attributable to Mosaic. The denominator for basic EPS is the weighted average number of shares outstanding during the period. The denominator for diluted EPS also includes the weighted average number of additional common shares that would have been outstanding if the dilutive potential common shares had been issued. The following is a reconciliation of the denominator for the basic and diluted EPS computations:
				Three months ended
				September 30,
				2013		2012
		Net earnings attributed to Mosaic	$	124.4	$	417.4
		Basic weighted average common shares outstanding		425.9		425.6
		Dilutive impact of share-based awards		1.2		1.2
		Diluted weighted average common shares outstanding		427.1		426.8
		Basic net earnings per share attributable to Mosaic	$	0.29	$	0.98
		Diluted net earnings per share attributable to Mosaic	$	0.29	$	0.98
	A total of 1.4 million and 0.9 million shares of common stock subject to issuance upon exercise of stock options for the three months ended September 30, 2013 and 2012, respectively, have been excluded from the calculation of diluted EPS as the effect would have been anti-dilutive.

Income_Taxes

Income Taxes	3 Months Ended
	Sep. 30, 2013
Income Taxes [Abstract]	'
Income Taxes	'
	6. Income Taxes
	We record unrecognized tax benefits in accordance with applicable accounting standards. During the three months ended September 30, 2013, gross unrecognized tax benefits decreased by $46.3 million to $270.5 million. We recorded a gross decrease of $69.7 million due to the resolution of certain tax matters in various jurisdictions, of which $17.0 million impacted our effective tax rate. The decrease was partially offset by a net increase in unrecognized tax benefits associated with the current and prior fiscal years. If recognized, approximately $97.7 million of the $270.5 million in unrecognized tax benefits would affect our effective tax rate in future periods.
	We recognize interest and penalties related to unrecognized tax benefits as a component of our income tax provision. We had accrued interest and penalties totaling $50.3 million and $53.8 million as of September 30, 2013 and May 31, 2013, respectively, that were included in other noncurrent liabilities in the Condensed Consolidated Balance Sheets.
	Based upon the information available as of September 30, 2013, we anticipate that the amount of uncertain tax positions will change in the next twelve months; however, the change cannot reasonably be estimated.

Inventories

Inventories	3 Months Ended
	Sep. 30, 2013
Inventories [Abstract]	'
Schedule of inventories	'
	7. Inventories
	Inventories consist of the following:
				September 30,		May 31,
				2013		2013
		Raw materials	$	27.6	$	43
		Work in process		415.9		445.8
		Finished goods		983.5		991.3
		Operating materials and supplies		68		77.2
			$	1,495.00	$	1,557.30

Goodwill

Goodwill	3 Months Ended
	Sep. 30, 2013
Goodwill [Abstract]	'
Goodwill	'
	8. Goodwill
	The changes in the carrying amount of goodwill, by reporting unit, are as follows:
			Phosphates		Potash		Total
		Balance as of May 31, 2013	$	546.6	$	1,298.00	$	1,844.60
		Foreign currency translation		-		-0.6		-0.6
		Reallocation of goodwill to assets held for sale		-10.8		-		-10.8
		Balance as of September 30, 2013	$	535.8	$	1,297.40	$	1,833.20
	We review goodwill for impairment annually or at any time events or circumstances indicate that the carrying value may not be fully recoverable. Under our accounting policy, an annual review is performed in November of each year, or more frequently if indicators of potential impairment exist.

Variable_Interest_Entities

Variable Interest Entities	3 Months Ended
	Sep. 30, 2013
Noncontrolling Interest [Abstract]	'
Schedule of variable interest entities	'
	9. Variable Interest Entities
	Mosaic is the primary beneficiary of and consolidates two VIEs within our Phosphates segment: PhosChem and South Fort Meade Partnership, L.P. (“SFMP”). We determine whether we are the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the purpose and design of the VIE, the risks that the VIE were designed to create and pass along to other entities, the activities of the VIE that could be directed and which entity could direct them, and the expected relative impact of those activities on the economic performance of the VIE. We assess our VIE determination with respect to an entity on an ongoing basis. We have not identified any additional VIEs in which we hold a significant interest.
	PhosChem is an export association of United States phosphate producers that markets our phosphate products internationally. We, along with the other member, are, subject to certain conditions and exceptions, contractually obligated to reimburse PhosChem for our respective pro rata share of any operating expenses or other liabilities. PhosChem had net sales of $228.0 million and $323.3 million for the three months ended September 30, 2013 and 2012, respectively, which are included in our consolidated net sales. PhosChem currently funds its operations through ongoing sales.
	We determined that, because we are PhosChem's exclusive export agent for the marketing, solicitation of orders and freighting of dry phosphatic materials, we have the power to direct the activities that most significantly impact PhosChem's economic performance. Because Mosaic accounts for the majority of sales volume marketed through PhosChem, we have the obligation to absorb losses or right to receive benefits that could be significant to PhosChem.
	SFMP owns the mineable acres at our South Fort Meade phosphate mine. We have a long-term mineral lease with SFMP which, in general, expires on the earlier of: (i) December 31, 2025, or (ii) the date that we have completed mining and reclamation obligations associated with the leased property. In addition to lease payments, we pay SFMP a royalty on each tonne mined and shipped from the areas that we lease. SFMP had no external sales for the three months ended September 30, 2013 and 2012.
	We determined that, because we control the day-to-day mining decisions and are responsible for obtaining mining permits, we have the power to direct the activities that most significantly impact SFMP's economic performance. Because of our rental and royalty payments to the partnership, we have the obligation to absorb losses or right to receive benefits that could potentially be significant to SFMP.
	No additional financial or other support has been provided to these VIE's beyond what was previously contractually required during any periods presented. The carrying amounts and classification of assets and liabilities included in our Condensed Consolidated Balance Sheets for these consolidated entities are as follows:
				September 30,		May 31,
				2013		2013
		Current assets	$	49.9	$	180.7
		Non current assets		45.2		46.9
		Total assets	$	95.1	$	227.6
		Current liabilities	$	10.2	$	5.4
		Total liabilities	$	10.2	$	5.4

Contingencies

Contingencies	3 Months Ended
	Sep. 30, 2013
Contingencies [Abstract]	'
Contingencies	'
	10. Contingencies
	We have described below judicial and administrative proceedings to which we are subject.
	We have contingent environmental liabilities that arise principally from three sources: (i) facilities currently or formerly owned by our subsidiaries or their predecessors; (ii) facilities adjacent to currently or formerly owned facilities; and (iii) third-party Superfund or state equivalent sites. At facilities currently or formerly owned by our subsidiaries or their predecessors, the historical use and handling of regulated chemical substances, crop and animal nutrients and additives and by-product or process tailings have resulted in soil, surface water and/or groundwater contamination. Spills or other releases of regulated substances, subsidence from mining operations and other incidents arising out of operations, including accidents, have occurred previously at these facilities, and potentially could occur in the future, possibly requiring us to undertake or fund cleanup or result in monetary damage awards, fines, penalties, other liabilities, injunctions or other court or administrative rulings. In some instances, pursuant to consent orders or agreements with governmental agencies, we are undertaking certain remedial actions or investigations to determine whether remedial action may be required to address contamination. At other locations, we have entered into consent orders or agreements with appropriate governmental agencies to perform required remedial activities that will address identified site conditions. Taking into consideration established accruals of approximately $23.7 million and $24.7 million as of September 30, 2013 and May 31, 2013, respectively, expenditures for these known conditions currently are not expected, individually or in the aggregate, to have a material effect on our business or financial condition. However, material expenditures could be required in the future to remediate the contamination at known sites or at other current or former sites or as a result of other environmental, health and safety matters. Below is a discussion of the more significant environmental matters.
	EPA RCRA Initiative. In 2003, the U.S. Environmental Protection Agency (“EPA”) Office of Enforcement and Compliance Assurance announced that it would be targeting facilities in mineral processing industries, including phosphoric acid producers, for a thorough review under the U.S. Resource Conservation and Recovery Act (“RCRA”) and related state laws. Mining and processing of phosphates generate residual materials that must be managed both during the operation of a facility and upon a facility's closure. Certain solid wastes generated by our phosphate operations may be subject to regulation under RCRA and related state laws. The EPA rules exempt “extraction” and “beneficiation” wastes, as well as 20 specified “mineral processing” wastes, from the hazardous waste management requirements of RCRA. Accordingly, certain of the residual materials which our phosphate operations generate, as well as process wastewater from phosphoric acid production, are exempt from RCRA regulation. However, the generation and management of other solid wastes from phosphate operations may be subject to hazardous waste regulation if the waste is deemed to exhibit a “hazardous waste characteristic.” As part of its initiative, we understand that EPA has inspected all or nearly all facilities in the U.S. phosphoric acid production sector to ensure compliance with applicable RCRA regulations and to address any “imminent and substantial endangerment” found by the EPA under RCRA. We have provided the EPA with substantial amounts of information regarding the process water recycling practices and the hazardous waste handling practices at our phosphate production facilities in Florida and Louisiana, and the EPA has inspected all of our currently operating processing facilities in the U.S. In addition to the EPA's inspections, our phosphates concentrates facilities have entered into consent orders to perform analyses of existing environmental data, to perform further environmental sampling as may be necessary, and to assess whether the facilities pose a risk of harm to human health or the surrounding environment.
	We have received Notices of Violation (“NOVs”) from the EPA related to the handling of hazardous waste at our Riverview (September 2005), New Wales (October 2005), Mulberry (June 2006), Green Bay (August 2006) and Bartow (September 2006) facilities in Florida. The EPA has issued similar NOVs to our competitors and referred the NOVs to the U.S. Department of Justice (“DOJ”) for further enforcement. We currently are engaged in discussions with the DOJ and EPA. We believe we have substantial defenses to allegations in the NOVs, including but not limited to previous EPA regulatory interpretations and inspection reports finding that the process water handling practices in question comply with the requirements of the exemption for extraction and beneficiation wastes. We intend to evaluate various alternatives and continue discussions to determine if a negotiated resolution can be reached. If it cannot, we intend to vigorously defend these matters in any enforcement actions that may be pursued.
	We are negotiating the terms of a possible settlement with the EPA, the DOJ, the Florida Department of Environmental Protection and the Louisiana Department of Environmental Quality (collectively, the “Government”) and the final terms are not yet agreed upon or approved. If a settlement can be achieved, in all likelihood our commitments would be multi-faceted with key elements including, in general and among other elements, the following:
	•        Incurring capital expenditures likely to exceed $150 million in the aggregate over a period of several years.
	•       Providing meaningful additional financial assurance for the estimated costs of closure and post-closure care of our Gypstacks (“Gypstack Closure Costs”). For financial reporting purposes, we recognize our estimated asset retirement obligations (“AROs”), including Gypstack Closure Costs, at their present value. This present value determined for financial reporting purposes is reflected on our Consolidated Balance Sheets in accrued liabilities and other noncurrent liabilities. As of May 31, 2013, the undiscounted amount of our AROs, determined using the assumptions used for financial reporting purposes, was approximately $1.5 billion and the present value of our Gypstack Closure Costs reflected in our Consolidated Balance Sheet was approximately $450 million. Currently, financial assurance requirements in Florida and Louisiana for Gypstack Closure Costs can be satisfied through a variety of methods, including satisfaction of financial tests. In the context of a potential settlement of the Government's enforcement action, we expect that we would agree to pre-fund a material portion of our Gypstack Closure Costs, primarily by depositing cash, currently estimated to be in the amount of approximately $625 million, into a trust fund which would increase over time with reinvestment of earnings. Amounts held in any such trust fund (including reinvested earnings) would be classified as restricted cash on our Consolidated Balance Sheets. We expect that any final settlement of this matter would resolve all of our financial assurance obligations to the Government for Gypstack Closure Costs. Our actual Gypstack Closure Costs are generally expected to be paid by us in the normal course of our Phosphates business over a period that may not end until three decades or more after a Gypstack has been closed.
	•        We have also established accruals to address the estimated cost of civil penalties in connection with this matter, which we do not believe in light of the relevant regulatory history, would be material to our results of operations, liquidity or capital resources.
	In light of our strong operating cash flows, liquidity and capital resources, we believe that we have sufficient liquidity and capital resources to be able to fund such capital expenditures, financial assurance requirements and civil penalties as part of a settlement. If a settlement cannot be agreed upon, we cannot predict the outcome of any litigation or estimate the potential amount or range of loss; however, we would face potential exposure to material costs should we fail in the defense of an enforcement action.
	EPA EPCRA Initiative. In July 2008, the DOJ sent a letter to major U.S. phosphoric acid manufacturers, including us, stating that the EPA's ongoing investigation indicates apparent violations of Section 313 of the Emergency Planning and Community Right-to-Know Act (“EPCRA”) at their phosphoric acid manufacturing facilities. Section 313 of EPCRA requires annual reports to be submitted with respect to the use or presence of certain toxic chemicals. DOJ and EPA also stated that they believe that a number of these facilities have violated Section 304 of EPCRA and Section 103 of the Comprehensive Environmental Response, Compensation and Liability Act (“CERCLA”) by failing to provide required notifications relating to the release of hydrogen fluoride from the facilities. The letter did not identify any specific violations by us or assert a demand for penalties against us. We cannot predict at this time whether the EPA and DOJ will initiate an enforcement action over this matter, what its scope would be, or what the range of outcomes of such a potential enforcement action might be.
	Florida Sulfuric Acid Plants. On April 8, 2010, the EPA Region 4 submitted an administrative subpoena to us under Section 114 of the Federal Clean Air Act (the “CAA”) regarding compliance of our Florida sulfuric acid plants with the “New Source Review” requirements of the CAA. The request received by Mosaic appears to be part of a broader EPA national enforcement initiative focusing on sulfuric acid plants. We cannot predict at this time whether the EPA and DOJ will initiate an enforcement action over this matter, what its scope would be, or what the range of outcomes of such a potential enforcement action might be.
	Other Environmental Matters. Superfund and equivalent state statutes impose liability without regard to fault or to the legality of a party's conduct on certain categories of persons who are considered to have contributed to the release of “hazardous substances” into the environment. Under Superfund, or its various state analogues, one party may, under certain circumstances, be required to bear more than its proportionate share of cleanup costs at a site where it has liability if payments cannot be obtained from other responsible parties. Currently, certain of our subsidiaries are involved or concluding involvement at several Superfund or equivalent state sites. Our remedial liability from these sites, alone or in the aggregate, currently is not expected to have a material effect on our business or financial condition. As more information is obtained regarding these sites and the potentially responsible parties involved, this expectation could change.
	We believe that, pursuant to several indemnification agreements, our subsidiaries are entitled to at least partial, and in many instances complete, indemnification for the costs that may be expended by us or our subsidiaries to remedy environmental issues at certain facilities. These agreements address issues that resulted from activities occurring prior to our acquisition of facilities or businesses from parties including, but not limited to, ARCO (BP); Beatrice Fund for Environmental Liabilities; Conoco; Conserv; Estech, Inc.; Kaiser Aluminum & Chemical Corporation; Kerr-McGee Inc.; PPG Industries, Inc.; The Williams Companies and certain other private parties. Our subsidiaries have already received and anticipate receiving amounts pursuant to the indemnification agreements for certain of their expenses incurred to date as well as future anticipated expenditures. Potential indemnification is not considered in our established accruals.
	Phosphate Mine Permitting in Florida
	Denial of the permits sought at any of our mines, issuance of the permits with cost-prohibitive conditions, or substantial delays in issuing the permits, legal actions that prevent us from relying on permits or revocation of permits may create challenges for us to mine the phosphate rock required to operate our Florida and Louisiana phosphate plants at desired levels or increase our costs in the future.
	The Altman Extension of the Four Corners Mine. The Army Corps of Engineers (the “Corps”) issued a federal wetlands permit under the Clean Water Act (the “CWA”) for mining the Altman Extension (the “Altman Extension”) of our Four Corners phosphate rock mine in central Florida in May 2008. The Sierra Club, Inc. (the “Sierra Club”), Manasota-88, Inc. (“Manasota-88”), Gulf Restoration Network, Inc., People for Protecting Peace River, Inc. (“People for Protecting Peace River”) and the Environmental Confederation of Southwest Florida, Inc. sued the Corps in the United States District Court for the Middle District of Florida, Jacksonville Division (the “Jacksonville District Court”), seeking to vacate our permit to mine the Altman Extension. On September 30, 2013, the Jacksonville District Court granted our motion for summary judgment and denied the plaintiffs' motion for summary judgment, resulting in dismissal of the plaintiffs' lawsuit. The time for the plaintiffs to appeal or request a rehearing has not yet expired.
	MicroEssentials® Patent Lawsuit
	On January 9, 2009, John Sanders and Specialty Fertilizer Products, LLC filed a complaint against Mosaic, Mosaic Fertilizer, LLC, Cargill, Incorporated and Cargill Fertilizer, Inc. in the United States District Court for the Western District of Missouri (the “Missouri District Court”). The complaint alleges that our production of MicroEssentials® SZ, one of several types of the MicroEssentials® value-added ammoniated phosphate crop nutrient products that we produce, infringes on a patent held by the plaintiffs since 2001. Plaintiffs have since asserted that other MicroEssentials® products also infringe the patent. Plaintiffs seek to enjoin the alleged infringement and to recover an unspecified amount of damages and attorneys' fees for past infringement. Our answer to the complaint responds that the plaintiffs' patent is invalid and we have counterclaimed that the plaintiffs have engaged in inequitable conduct.
	The Missouri District Court stayed the lawsuit pending an ex parte reexamination of plaintiffs' patent claims by the U.S. Patent and Trademark Office (the “PTO”). On September 12, 2012, Shell Oil Company (“Shell”) filed an inter parties reexamination request which in part asserted that the claims as amended and added in connection with the ex parte reexamination are unpatentable. On October 4, 2012, the PTO issued an Ex Parte Reexamination Certificate in which certain claims of the plaintiffs' patent were cancelled, disclaimed and amended, and new claims were added. Plaintiffs have filed a motion with the Missouri District Court requesting that the stay of the lawsuit be lifted, and we have opposed that motion. On November 28, 2012, the PTO granted Shell's request for an inter parties reexamination. On December 11, 2012, as part of that reexamination, the PTO issued an initial rejection of all of plaintiffs' remaining patent claims. On September 12, 2013, the PTO reversed its initial rejection of the plaintiffs' remaining patent claims and allowed them to stand. The time for Shell to appeal the PTO's decision has not yet expired. A successful appeal by Shell could limit the claims the plaintiffs can assert against us or their remedies against us.
	We believe that the plaintiffs' allegations are without merit and intend to defend vigorously against them. At this stage of the proceedings, we cannot predict the outcome of this litigation, estimate the potential amount or range of loss or determine whether it will have a material effect on our results of operations, liquidity or capital resources.
	Brazil Tax Contingencies
	Our Brazilian subsidiary is engaged in a number of judicial and administrative proceedings relating to various non-income tax matters. We estimate that our maximum potential liability with respect to these matters is approximately $96 million. Approximately $52 million of the maximum potential liability relates to PIS and Cofins tax credit cases while the majority of the remaining amount relates to various other non-income tax cases such as value added taxes. In the event that the Brazilian government was to prevail in connection with all judicial and administrative matters involving us and considering the amount of judicial deposits made, our maximum cash tax liability with respect to these matters would be approximately $94 million. Based on the current status of similar tax cases involving unrelated taxpayers, we believe we have recorded adequate accruals, which are immaterial, for the probable liability with respect to these Brazilian judicial and administrative proceedings.
	Other Claims
	We also have certain other contingent liabilities with respect to judicial, administrative and arbitration proceedings and claims of third parties, including tax matters, arising in the ordinary course of business. We do not believe that any of these contingent liabilities will have a material adverse impact on our business or financial condition, results of operations, and cash flows.

Accounting_for_Derivative_Inst

Accounting for Derivative Instruments and Hedging Activities	3 Months Ended
	Sep. 30, 2013
Accounting For Derivative Instruments And Hedging Activities [Abstract]	'
Accounting for Derivative Instruments and Hedging Activities	'
	11. Accounting for Derivative Instruments and Hedging Activities
	We are exposed to the impact of fluctuations in the relative value of currencies, the impact on interest rates, the impact of fluctuations in the purchase prices of natural gas, ammonia and sulfur consumed in operations and changes in freight costs. We periodically enter into derivatives in order to mitigate our foreign currency risks, interest rate risks and the effects of changing commodity and freight prices, but not for speculative purposes.
	As of September 30, 2013 and May 31, 2013, the following is the total absolute notional volume associated with our outstanding derivative instruments:
		(in millions of Units)						September 30,		May 31,
		Derivative Instrument		Derivative Category		Unit of Measure		2013		2013
		Foreign currency derivatives		Foreign currency		US Dollars		944		1,459.70
		Natural gas derivatives		Commodity		MMbtu		10.6		15.2
		Ocean freight contracts		Freight		Tonnes		0.8		1.5
	We do not apply hedge accounting treatments to our foreign currency exchange contracts, commodities contracts, and freight contracts. Unrealized gains and losses on foreign currency exchange contracts used to hedge cash flows related to the production of our products are included in cost of goods sold in the Condensed Consolidated Statements of Earnings. Unrealized gains and losses on commodities contracts and certain forward freight agreements are also recorded in cost of goods sold in the Condensed Consolidated Statements of Earnings. Unrealized gain or loss on foreign currency exchange contracts used to hedge cash flows that are not related to the production of our products are included in the foreign currency transaction gain (loss) line in the Condensed Consolidated Statements of Earnings. Below is a table that shows the unrealized gains and (losses) on derivative instruments related to foreign currency exchange contracts, commodities contracts, and freight:
							Three months ended
							September 30,
		Derivative Instrument		Location			2013			2012
		Foreign currency derivatives		Cost of goods sold		$	22.6		$	17.7
		Foreign currency derivatives		Foreign currency transaction gain (loss)			-1			0.5
		Commodity derivatives		Cost of goods sold			2.7			5.9
		Freight derivatives		Cost of goods sold			-1.1			0.2
	The gross fair market value of all derivative instruments and their location in our Condensed Consolidated Balance Sheets are shown in the table below by asset or liability position and are further categorized by foreign currency, commodity, and freight derivatives:.
					Asset Derivatives				Liability Derivatives
							September 30,				September 30,
		Derivative Instrument			Location		2013		Location		2013
		Foreign currency derivatives			Other current assets	$	8.1		Accrued liabilities	$	-16.4
		Commodity derivatives			Other current assets		3.2		Accrued liabilities		-6.7
		Commodity derivatives			Other assets		-		Other noncurrent liabilities		-0.5
		Freight derivatives			Other current assets		1.9		Accrued liabilities		-0.1
			Total			$	13.2			$	-23.7
					Asset Derivatives				Liability Derivatives
							May 31,				May 31,
		Derivative Instrument			Location		2013		Location		2013
		Foreign currency derivatives			Other current assets	$	10.7		Accrued liabilities	$	-38.6
		Commodity derivatives			Other current assets		4.8		Accrued liabilities		-6.1
		Commodity derivatives			Other assets		0.2		Other noncurrent liabilities		-
		Freight derivatives			Other current assets		1.7		Accrued liabilities		-0.4
			Total			$	17.4			$	-45.1
	We have entered into forward-starting interest rate swaps in anticipation of future debt issuance. These swap contracts are designated as cash flow hedges with unrealized gains and losses deferred to other comprehensive income and will be reclassified into earnings over the life of the associated debt once these contracts are settled. As of September 30, 2013, the total notional value of these swaps was $1.5 billion, with $1.25 billion related to ten-year term debt and $250.0 million related to thirty-year term debt. The fair market value of these contracts was ($1.9) million, with $7.3 million accounted as assets and $9.2 million accounted as liabilities as of September 30, 2013. These swap contracts will be settled in November 2013, or upon the earlier issuance of debt.
	For additional disclosures about fair value measurement of derivative instruments, see Note 12 to the Condensed Consolidated Financial Statements in this report.
	Credit-Risk-Related Contingent Features
	Certain of our derivative instruments contain provisions that are governed by International Swap and Derivatives Association (“ISDA”) agreements with the counterparties. These agreements contain provisions that allow us to settle for the net amount between payments and receipts, and also state that if our debt were to be rated below investment grade, certain counterparties could request full collateralization on derivative instruments in net liability positions. The aggregate fair value of all derivative instruments with credit-risk-related contingent features that were in a liability position as of September 30, 2013, was $18.8 million. We have no cash collateral posted in association with these contracts. If the credit-risk-related contingent features underlying these agreements were triggered on September 30, 2013, we would be required to post $16.2 million of collateral assets, which are either cash or U.S. Treasury instruments, to the counterparties.
	Counterparty Credit Risk
	We enter into foreign exchange and certain commodity and interest rate derivatives, primarily with a diversified group of highly rated counterparties. We continually monitor our positions and the credit ratings of the counterparties involved and limit the amount of credit exposure to any one party. While we may be exposed to potential losses due to the credit risk of non-performance by these counterparties, material losses are not anticipated. We closely monitor the credit risk associated with our counterparties and customers and to date have not experienced material losses

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	12. Fair Value Measurements
	We determine the fair market values of our derivative contracts and certain other assets and liabilities based on the fair value hierarchy, described below, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. There are three levels within the fair value hierarchy that may be used to measure fair value:
	Level 1: Values based on unadjusted quoted prices in active markets that are accessible at the measurement date for identical assets or liabilities.
	Level 2: Values based on quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, or model-based valuation techniques for which all significant assumptions are observable in the market.
	Level 3: Values generated from model-based techniques that use significant assumptions not observable in the market. These unobservable assumptions reflect our own estimates of assumptions that market participants would use in pricing the asset or liability. Valuation techniques include use of option pricing models, discounted cash flow models and similar techniques.
	Assets and Liabilities Measured at Fair Value on a Recurring Basis
	The following table presents assets and liabilities included in our Condensed Consolidated Balance Sheets that are recognized at fair value on a recurring basis, and indicate the fair value hierarchy utilized to determine such fair values.
						30-Sep-13
						Total			Level 1			Level 2			Level 3
		Assets
		Foreign currency derivatives			$	8.1		$	1		$	7.1		$	-
		Commodity derivatives				3.2			-			3.2			-
		Freight derivatives				1.9			-			-			1.9
			Total assets at fair value		$	13.2		$	1		$	10.3		$	1.9
		Liabilities
		Foreign currency derivatives			$	16.4		$	3.7		$	12.7		$	-
		Commodity derivatives				7.2			-			7.2			-
		Freight derivatives				0.1			-			-			0.1
			Total liabilities at fair value		$	23.7		$	3.7		$	19.9		$	0.1
	We did not significantly change our valuation techniques from prior periods.
	Financial Instruments
	The carrying amounts and estimated fair values of our financial instruments are as follows:
					30-Sep-13						31-May-13
					Carrying			Fair			Carrying			Fair
					Amount			Value			Amount			Value
		Cash and cash equivalents		$	3,338.60		$	3,338.60		$	3,697.10		$	3,697.10
		Receivables, net			478.7			478.7			1,015.70			1,015.70
		Accounts payable trade			611.7			611.7			763.1			763.1
		Short-term debt			14.5			14.5			68.7			68.7
		Long-term debt, including current portion			1,012.30			1,032.80			1,010.50			1,093.30
	For cash and cash equivalents, receivables, net, accounts payable trade and short-term debt, the carrying amount approximates fair value because of the short-term maturity of those instruments. The fair value of long-term debt, including current portion, is estimated using quoted market prices for the publicly registered notes and debentures, classified as Level 1 and Level 2, respectively, within the fair value hierarchy, depending on the market liquidity of the debt.

Related_Party_Transactions

Related Party Transactions	3 Months Ended
	Sep. 30, 2013
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	13. Related Party Transactions
	We enter into transactions and agreements with certain of our non-consolidated companies from time to time. As of September 30, 2013 and May 31, 2013, the net amount due from our non-consolidated companies totaled $23.6 million and $145.8 million, respectively.
	The Condensed Consolidated Statements of Earnings included the following transactions with our non-consolidated companies:
					Three months ended
					September 30,
					2013		2012
		Transactions with non-consolidated companies
			included in net sales	$	191.8	$	248.2
		Transactions with non-consolidated companies
			included in cost of goods sold		76.1		141.2

Business_Segments

Business Segments	3 Months Ended
	Sep. 30, 2013
Business Segments [Abstract]	'
Business Segments	'
	14. Business Segments
	The reportable segments are determined by management based upon factors such as products and services, production processes, technologies, market dynamics, and for which segment financial information is available for our chief operating decision maker. For a description of our business segments see Note 1 to the Condensed Consolidated Financial Statements in this report. We evaluate performance based on the operating earnings of the respective business segments, which includes certain allocations of corporate selling, general and administrative expenses. The segment results may not represent the actual results that would be expected if they were independent, stand-alone businesses. Corporate, Eliminations and Other primarily represents activities associated with our nitrogen distribution business, unallocated corporate office activities and eliminations. All intersegment transactions are eliminated within Corporate, Eliminations and Other. Segment information was as follows:
					Phosphates		Potash		Corporate, Eliminations and Other		Total
		Three months ended September 30, 2013
		Net sales to external customers		$	1,418.80	$	488.5	$	1.4	$	1,908.70
		Intersegment net sales			-		34.7		-34.7		-
		Net sales			1,418.80		523.2		-33.3		1,908.70
		Gross margin			193.3		184.4		9.2		386.9
		Operating earnings			57.6		91.8		-5.3		144.1
		Capital expenditures			119.9		199.2		13.4		332.5
		Depreciation, depletion and
			amortization expense		75.6		85.5		5		166.1
		Three months ended September 30, 2012
		Net sales to external customers		$	1,740.60	$	902.5	$	2.6	$	2,645.70
		Intersegment net sales			-		24.6		-24.6		-
		Net sales			1,740.60		927.1		-22		2,645.70
		Gross margin			328.9		440.9		4.8		774.6
		Operating earnings			246.2		398.1		-0.6		643.7
		Capital expenditures			99.7		263.9		21		384.6
		Depreciation, depletion and
			amortization expense		70.1		67.1		3.4		140.6

Investment_in_a_Joint_Venture

Investment in a Joint Venture	3 Months Ended
	Sep. 30, 2013
Investment in a Joint Venture [Abstract]	'
Investment in in a Joint Venture	'
	15. Investment in a Joint Venture
	On August 5, 2013, we entered into a Shareholders' Agreement with Saudi Arabian Mining Company (“Ma'aden”) and Saudi Basic Industries Corporation (“SABIC”) to form a joint venture which will develop, own and operate integrated phosphate production facilities in the Kingdom of Saudi Arabia. The approximately $7 billion greenfield project will be financed by the joint venture with debt and the investments of the parties, and have a production capacity of approximately 3.5 million tonnes of finished product. Operations are expected to commence in late calendar 2016. We will have a 25% interest in the joint venture.
	In connection with our equity share, we will market approximately 25% of the production of the joint venture. Our cash investment is expected to be approximately $1 billion, funded over a four-year period. As of September 30, 2013, our investment is $156 million.

Assets_Held_for_Sale

Assets Held for Sale	3 Months Ended
	Sep. 30, 2013
Assets Held For Sale [Abstract]	'
Assets Held for Sale [Text Block]	'
	16. Assets Held for Sale
	During the quarter ended September 30, 2013, we decided to exit our distribution businesses in Argentina and Chile. In connection with this decision, we wrote down the related assets by approximately $50 million pre-tax to their estimated fair value, which is included in loss on write down of assets in the Condensed Consolidated Statement of Earnings. There was no tax benefit recorded related to this write down. At September 30, 2013, we included $232.6 million in other current assets and $45.9 million in accrued liabilities in our balance sheet as these qualify for asset held for sale accounting. We expect to continue to sell our products in these countries by using other distribution channels.
	Also, during the quarter ended September 30, 2013, we decided to sell the salt operations of our Hersey, Michigan mine and close the related potash operations. We are currently decommissioning the potash assets which precluded the Hersey facility from qualifying as an asset held for sale at September 30, 2013. In connection with the planned sale of this mine we wrote down the related assets by approximately $48 million pre-tax to their estimated fair value and recorded a corresponding tax benefit of approximately $17 million.

Subsequent_Event

Subsequent Event	3 Months Ended
	Sep. 30, 2013
Subsequent Events [Abstract]	'
Subsequent Event	'
	17. Subsequent Event
	On October 28, 2013, we entered into an agreement to acquire the Florida phosphate assets and assume certain related liabilities of CF Industries, Inc. (“CF”) for $1.2 billion plus an additional $200 million to fund CF's asset retirement obligation escrow (the “CF Phosphate Assets Acquisition”). Under the terms of the agreement, we would acquire CF's phosphate mining and production operations in Central Florida and terminal and warehouse facilities in Tampa, Florida. These facilities currently produce approximately 1.8 million tonnes of phosphate fertilizer per year. This transaction is expected to close in the first half of 2014. Customary regulatory approvals are required.
	We also signed strategic supply agreements with CF under which CF will provide us with ammonia (the “CF Ammonia Supply Agreements”). Under one of the agreements, we will purchase approximately 545,000 to 725,000 tonnes annually for up to fifteen years at a price tied to the prevailing price of U.S. natural gas. This agreement is expected to commence prior to January 1, 2017. Under a second agreement, we would purchase approximately 270,000 tonnes annually for three years from CF's Trinidad operations at CFR Tampa market-based pricing. In light of these supply arrangements, we have decided to forego our proposed ammonia manufacturing plant at our Faustina, Louisiana facility. Therefore, at September 30, 2013, we wrote off our initial investment in the Faustina project of approximately $25 million and recorded a corresponding tax benefit of $9 million.

Additional_Financial_Informati

Additional Financial Information	4 Months Ended
	Sep. 30, 2013
Additional Financial Information [Abstract]	'
Additional Financial Information Disclosure	'
	18. Additional Financial Information
	The condensed consolidated statement of earnings for the four months ended September 30, 2013 is as follows:
				Four months ended
		In millions		September 30,
		(Unaudited)		2013
		Net sales	$	2,584.30
		Cost of goods sold		2,077.50
		Gross margin		506.8
		Selling, general and administrative expenses		120.6
		Loss on write down of assets		122.8
		Other operating expense		25.5
		Operating earnings		237.9
		Interest income (expense), net		-1.3
		Foreign currency transaction gain (loss)		-8.6
		Other expense		0.2
		Earnings from consolidated companies before income taxes		228.2
		Provision for income taxes		21.4
		Earnings from consolidated companies		206.8
		Equity in net earnings (loss) of nonconsolidated companies		6
		Net earnings including noncontrolling interests		212.8
		Less: Net earnings (loss) attributable to noncontrolling interests		1.8
		Net earnings attributable to Mosaic	$	211
	The following table represents the net cash provided by operating activities, net cash used in investing activities, and net cash used in financing activities for the 4 months ended September 30, 2013:
				Four months ended
		In millions		September 30,
		(Unaudited)		2013
		Net cash provided by operating activities	$	388.9
		Net cash used in investing activities		-603.2
		Net cash used in financing activities		-136.2

Significant_Accounting_Policie

Significant Accounting Policies (Policies)	3 Months Ended
	Sep. 30, 2013
Significant Accounting Policies Disclosure [Abstract]	'
Basis of Consolidation	'
	Statement Presentation and Basis of Consolidation
	The accompanying unaudited Condensed Consolidated Financial Statements of Mosaic have been prepared on the accrual basis of accounting and in accordance with the requirements of the Securities and Exchange Commission (“SEC”) for interim financial reporting. As permitted under these rules, certain footnotes and other financial information that are normally required by accounting principles generally accepted in the United States (“U.S. GAAP”) can be condensed or omitted. The Condensed Consolidated Financial Statements included in this document reflect, in the opinion of our management, all adjustments (consisting of only normal recurring adjustments) necessary for a fair statement of the results for the interim periods presented. The following notes should be read in conjunction with the accounting policies and other disclosures in the Notes to the Consolidated Financial Statements included in our Annual Report on Form 10-K filed with the SEC for the fiscal year ended May 31, 2013. Sales, expenses, cash flows, assets and liabilities can and do vary during the year as a result of seasonality and other factors. Therefore, interim results are not necessarily indicative of the results to be expected for the full fiscal year.
	The accompanying Condensed Consolidated Financial Statements include the accounts of Mosaic and its majority owned subsidiaries, as well as the accounts of certain variable interest entities (“VIEs”) for which we are the primary beneficiary. Certain investments in companies where we do not have control but have the ability to exercise significant influence are accounted for by the equity method.
Accounting Estimates	'
	Accounting Estimates
	Preparation of the Condensed Consolidated Financial Statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of net sales and expenses during the reporting periods. The more significant estimates made by management relate to the recoverability of non-current assets, the useful lives of long-lived assets, environmental and reclamation liabilities, the costs of our employee benefit obligations for pension plans and postretirement benefits, income tax-related accounts, including the valuation allowance against deferred income tax assets, Canadian resource taxes and royalties, inventory valuation and accruals for pending legal matters. Actual results could differ from these estimates.
Interest and Penalties on Taxes	'
	We recognize interest and penalties related to unrecognized tax benefits as a component of our income tax provision.
Goodwill	'
	We review goodwill for impairment annually or at any time events or circumstances indicate that the carrying value may not be fully recoverable. Under our accounting policy, an annual review is performed in November of each year, or more frequently if indicators of potential impairment exist.
Fair Value	'
	We determine the fair market values of our derivative contracts and certain other assets and liabilities based on the fair value hierarchy, described below, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. There are three levels within the fair value hierarchy that may be used to measure fair value:
	Level 1: Values based on unadjusted quoted prices in active markets that are accessible at the measurement date for identical assets or liabilities.
	Level 2: Values based on quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, or model-based valuation techniques for which all significant assumptions are observable in the market.
	Level 3: Values generated from model-based techniques that use significant assumptions not observable in the market. These unobservable assumptions reflect our own estimates of assumptions that market participants would use in pricing the asset or liability. Valuation techniques include use of option pricing models, discounted cash flow models and similar techniques.
Business Segments	'
	The reportable segments are determined by management based upon factors such as products and services, production processes, technologies, market dynamics, and for which segment financial information is available for our chief operating decision maker.
	We evaluate performance based on the operating earnings of the respective business segments, which includes certain allocations of corporate selling, general and administrative expenses.
	All intersegment transactions are eliminated within Corporate, Eliminations and Other.

Other_Financial_Statement_Data1

Other Financial Statement Data (Tables)	3 Months Ended
	Sep. 30, 2013
Other Financial Statement Data [Abstract]	'
Other Financial Statement Data	'
	4. Other Financial Statement Data
	The following provides additional information concerning selected balance sheet accounts:
				September 30,		May 31,
	(in millions)			2013		2013
	Other current assets
		Final price deferred(a)	$	270.2	$	137.1
		Income and other taxes receivable		289.7		267.6
		Prepaid expenses		92		98.2
		Assets held for sale(b)		232.6		-
		Other		13.3		31.8
			$	897.8	$	534.7
	Accrued liabilities
		Non-income taxes	$	28.5	$	81.1
		Payroll and employee benefits		93.7		146.6
		Asset retirement obligations		95		83.5
		Customer prepayments		126.9		243.3
		Other		244.6		290.6
			$	588.7	$	845.1
	Other noncurrent liabilities
		Asset retirement obligations	$	564.1	$	575
		Accrued pension and postretirement benefits		125.1		140.7
		Unrecognized tax benefits		7.9		45.2
		Other		133.7		146.3
			$	830.8	$	907.2
	(a)Final price deferred is product that has shipped to customers, but the price has not yet been agreed upon. This has not been included in inventory as it is not held for sale.
	(b)See further description of assets held for sale in Footnote 16.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Schedule of earnings per share	'
	The following is a reconciliation of the denominator for the basic and diluted EPS computations:
				Three months ended
				September 30,
				2013		2012
		Net earnings attributed to Mosaic	$	124.4	$	417.4
		Basic weighted average common shares outstanding		425.9		425.6
		Dilutive impact of share-based awards		1.2		1.2
		Diluted weighted average common shares outstanding		427.1		426.8
		Basic net earnings per share attributable to Mosaic	$	0.29	$	0.98
		Diluted net earnings per share attributable to Mosaic	$	0.29	$	0.98

Inventories_Tables

Inventories (Tables)	3 Months Ended
	Sep. 30, 2013
Inventories [Abstract]	'
Schedule of inventories	'
	Inventories consist of the following:
				September 30,		May 31,
				2013		2013
		Raw materials	$	27.6	$	43
		Work in process		415.9		445.8
		Finished goods		983.5		991.3
		Operating materials and supplies		68		77.2
			$	1,495.00	$	1,557.30

Goodwill_Tables

Goodwill (Tables)	3 Months Ended
	Sep. 30, 2013
Goodwill [Abstract]	'
Goodwill	'
	The changes in the carrying amount of goodwill, by reporting unit, are as follows:
			Phosphates		Potash		Total
		Balance as of May 31, 2013	$	546.6	$	1,298.00	$	1,844.60
		Foreign currency translation		-		-0.6		-0.6
		Reallocation of goodwill to assets held for sale		-10.8		-		-10.8
		Balance as of September 30, 2013	$	535.8	$	1,297.40	$	1,833.20

Variable_Interest_Entities_Tab

Variable Interest Entities (Tables)	3 Months Ended
	Sep. 30, 2013
Noncontrolling Interest [Abstract]	'
Schedule of variable interest entities	'
	The carrying amounts and classification of assets and liabilities included in our Condensed Consolidated Balance Sheets for these consolidated entities are as follows:
				September 30,		May 31,
				2013		2013
		Current assets	$	49.9	$	180.7
		Non current assets		45.2		46.9
		Total assets	$	95.1	$	227.6
		Current liabilities	$	10.2	$	5.4
		Total liabilities	$	10.2	$	5.4

Accounting_for_Derivative_Inst1

Accounting for Derivative Instruments and Hedging Activities (Tables)	3 Months Ended
	Sep. 30, 2013
Accounting For Derivative Instruments And Hedging Activities [Abstract]	'
Schedule Of Derivative Instruments Notional Amounts	'
	As of September 30, 2013 and May 31, 2013, the following is the total absolute notional volume associated with our outstanding derivative instruments:
		(in millions of Units)						September 30,		May 31,
		Derivative Instrument		Derivative Category		Unit of Measure		2013		2013
		Foreign currency derivatives		Foreign currency		US Dollars		944		1,459.70
		Natural gas derivatives		Commodity		MMbtu		10.6		15.2
		Ocean freight contracts		Freight		Tonnes		0.8		1.5
Schedule of unrealized gains (losses) on derivative instruments related to foreign currency exchange contracts, commodities contracts and freight and their location in our Condensed Consolidated Statements of Earnings	'
	Below is a table that shows the unrealized gains and (losses) on derivative instruments related to foreign currency exchange contracts, commodities contracts, and freight:
							Three months ended
							September 30,
		Derivative Instrument		Location			2013			2012
		Foreign currency derivatives		Cost of goods sold		$	22.6		$	17.7
		Foreign currency derivatives		Foreign currency transaction gain (loss)			-1			0.5
		Commodity derivatives		Cost of goods sold			2.7			5.9
		Freight derivatives		Cost of goods sold			-1.1			0.2
Schedule of gross fair market value of all derivative instruments and their location in our Condensed Consolidated Statements of Earnings	'
	The gross fair market value of all derivative instruments and their location in our Condensed Consolidated Balance Sheets are shown in the table below by asset or liability position and are further categorized by foreign currency, commodity, and freight derivatives:.
					Asset Derivatives				Liability Derivatives
							September 30,				September 30,
		Derivative Instrument			Location		2013		Location		2013
		Foreign currency derivatives			Other current assets	$	8.1		Accrued liabilities	$	-16.4
		Commodity derivatives			Other current assets		3.2		Accrued liabilities		-6.7
		Commodity derivatives			Other assets		-		Other noncurrent liabilities		-0.5
		Freight derivatives			Other current assets		1.9		Accrued liabilities		-0.1
			Total			$	13.2			$	-23.7
					Asset Derivatives				Liability Derivatives
							May 31,				May 31,
		Derivative Instrument			Location		2013		Location		2013
		Foreign currency derivatives			Other current assets	$	10.7		Accrued liabilities	$	-38.6
		Commodity derivatives			Other current assets		4.8		Accrued liabilities		-6.1
		Commodity derivatives			Other assets		0.2		Other noncurrent liabilities		-
		Freight derivatives			Other current assets		1.7		Accrued liabilities		-0.4
			Total			$	17.4			$	-45.1

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Schedule of assets and liabilities included in our Condensed Consolidated Balance Sheets that are recognized at fair value on a recurring basis, and indicates the fair value heirarchy utilized to determine such fair value	'
	The following table presents assets and liabilities included in our Condensed Consolidated Balance Sheets that are recognized at fair value on a recurring basis, and indicate the fair value hierarchy utilized to determine such fair values.
						30-Sep-13
						Total			Level 1			Level 2			Level 3
		Assets
		Foreign currency derivatives			$	8.1		$	1		$	7.1		$	-
		Commodity derivatives				3.2			-			3.2			-
		Freight derivatives				1.9			-			-			1.9
			Total assets at fair value		$	13.2		$	1		$	10.3		$	1.9
		Liabilities
		Foreign currency derivatives			$	16.4		$	3.7		$	12.7		$	-
		Commodity derivatives				7.2			-			7.2			-
		Freight derivatives				0.1			-			-			0.1
			Total liabilities at fair value		$	23.7		$	3.7		$	19.9		$	0.1
Schedule of carrying amounts and estimated fair values of our financial instruments	'
	The carrying amounts and estimated fair values of our financial instruments are as follows:
					30-Sep-13						31-May-13
					Carrying			Fair			Carrying			Fair
					Amount			Value			Amount			Value
		Cash and cash equivalents		$	3,338.60		$	3,338.60		$	3,697.10		$	3,697.10
		Receivables, net			478.7			478.7			1,015.70			1,015.70
		Accounts payable trade			611.7			611.7			763.1			763.1
		Short-term debt			14.5			14.5			68.7			68.7
		Long-term debt, including current portion			1,012.30			1,032.80			1,010.50			1,093.30

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	3 Months Ended
	Sep. 30, 2013
Related Party Transactions [Abstract]	'
Schedule of related party transactions	'
	The Condensed Consolidated Statements of Earnings included the following transactions with our non-consolidated companies:
					Three months ended
					September 30,
					2013		2012
		Transactions with non-consolidated companies
			included in net sales	$	191.8	$	248.2
		Transactions with non-consolidated companies
			included in cost of goods sold		76.1		141.2

Business_Segments_Tables

Business Segments (Tables)	3 Months Ended
	Sep. 30, 2013
Business Segments [Abstract]	'
Schedule of segment reporting by segment	'
	Segment information was as follows:
					Phosphates		Potash		Corporate, Eliminations and Other		Total
		Three months ended September 30, 2013
		Net sales to external customers		$	1,418.80	$	488.5	$	1.4	$	1,908.70
		Intersegment net sales			-		34.7		-34.7		-
		Net sales			1,418.80		523.2		-33.3		1,908.70
		Gross margin			193.3		184.4		9.2		386.9
		Operating earnings			57.6		91.8		-5.3		144.1
		Capital expenditures			119.9		199.2		13.4		332.5
		Depreciation, depletion and
			amortization expense		75.6		85.5		5		166.1
		Three months ended September 30, 2012
		Net sales to external customers		$	1,740.60	$	902.5	$	2.6	$	2,645.70
		Intersegment net sales			-		24.6		-24.6		-
		Net sales			1,740.60		927.1		-22		2,645.70
		Gross margin			328.9		440.9		4.8		774.6
		Operating earnings			246.2		398.1		-0.6		643.7
		Capital expenditures			99.7		263.9		21		384.6
		Depreciation, depletion and
			amortization expense		70.1		67.1		3.4		140.6

Additional_Financial_Informati1

Additional Financial Information (Tables)	4 Months Ended
	Sep. 30, 2013
Additional Financial Information [Table Text Block]	'
4 Month - Condensed Consolidated Statement of Earnings	'
	The condensed consolidated statement of earnings for the four months ended September 30, 2013 is as follows:
				Four months ended
		In millions		September 30,
		(Unaudited)		2013
		Net sales	$	2,584.30
		Cost of goods sold		2,077.50
		Gross margin		506.8
		Selling, general and administrative expenses		120.6
		Loss on write down of assets		122.8
		Other operating expense		25.5
		Operating earnings		237.9
		Interest income (expense), net		-1.3
		Foreign currency transaction gain (loss)		-8.6
		Other expense		0.2
		Earnings from consolidated companies before income taxes		228.2
		Provision for income taxes		21.4
		Earnings from consolidated companies		206.8
		Equity in net earnings (loss) of nonconsolidated companies		6
		Net earnings including noncontrolling interests		212.8
		Less: Net earnings (loss) attributable to noncontrolling interests		1.8
		Net earnings attributable to Mosaic	$	211
4 month - Condensed Consolidated Cash Flow Statement	'
	The following table represents the net cash provided by operating activities, net cash used in investing activities, and net cash used in financing activities for the 4 months ended September 30, 2013:
				Four months ended
		In millions		September 30,
		(Unaudited)		2013
		Net cash provided by operating activities	$	388.9
		Net cash used in investing activities		-603.2
		Net cash used in financing activities		-136.2

Organization_and_Nature_of_Bus1

Organization and Nature of Business (Details)	3 Months Ended
	Sep. 30, 2013
Organization And Nature Of Business [Abstract]	'
Our percentage share of PhosChem's dry crop nutrient products	93.00%
Economic interest percentage in Miski Mayo mine joint venture in the Bayovar region of Peru	35.00%

Other_Financial_Statement_Data2

Other Financial Statement Data (Details) (USD $)	Sep. 30, 2013	31-May-13
In Millions, unless otherwise specified
Other current assets	'	'
Future price deferreds	$270.20	$137.10
Income taxes receivable	289.7	267.6
Prepaid expenses	92	98.2
Assets held for sale	232.6	0
Other	13.3	31.8
Total other current assets	897.8	534.7
Accrued liabilities	'	'
Customer prepayments	126.9	243.3
Payroll and employee benefits	93.7	146.6
Non-income taxes	28.5	81.1
Asset retirement obligations	95	83.5
Other	244.6	290.6
Total accrued liabilities, current	588.7	845.1
Other noncurrent liabilities	'	'
Asset retirement obligations	564.1	575
Unrecognized tax benefits	7.9	45.2
Accrued pension and postretirement benefits	125.1	140.7
Other	133.7	146.3
Total other noncurrent liabilities	$830.80	$907.20

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended		4 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]	'	'	'
Net earnings attributable to Mosaic	$124.40	$417.40	$211
Basic weighted average common shares outstanding	425.9	425.6	'
Dilutive impact of share-based awards	1.2	1.2	'
Diluted weighted average number of shares outstanding	427.1	426.8	'
Basic net earnings per share attributable to Mosaic	$0.29	$0.98	'
Diluted net earnings per share attributable to Mosaic	$0.29	$0.98	'
Earnings Per Share Additional Disclosure [Abstract]	'	'	'
Shares subject to issuance upon exercise of stock options	1.4	0.9	'

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	31-May-13
Unrecognized Tax Benefits [Abstract]	'	'
Change in unrecognized tax benefit	$46.30	'
Unrecognized Tax Benefits	270.5	'
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	97.7	'
Unrecognized Tax Benefits Decreases Resulting From SettlementsWithTaxingAuthorities	69.7	'
Gross decrease that impacts our effective tax rate due to the resolution of certain tax matters	-17	'
Interest And Penalties [Abstract]	'	'
Interest and penalties related to unrecognized tax benefits - Accrued	$50.30	$53.80

Inventories_Details

Inventories (Details) (USD $)	Sep. 30, 2013	31-May-13
In Millions, unless otherwise specified
Inventories [Abstract]	'	'
Raw materials	$27.60	$43
Work in process	415.9	445.8
Finished goods	983.5	991.3
Operating materials and supplies	68	77.2
Total Inventory	$1,495	$1,557.30

Goodwill_Details

Goodwill (Details) (USD $)	4 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Goodwill [Line Items]	'
Beginning Balance	$1,844.60
Foreign currency translation	-0.6
Reallocation of goodwill to assets held for sale	-10.8
Ending Balance	1,833.20
Phosphates Segment [Member]	'
Goodwill [Line Items]	'
Beginning Balance	546.6
Foreign currency translation	0
Reallocation of goodwill to assets held for sale	-10.8
Ending Balance	535.8
Potash Segment [Member]	'
Goodwill [Line Items]	'
Beginning Balance	1,298
Foreign currency translation	-0.6
Reallocation of goodwill to assets held for sale	0
Ending Balance	$1,297.40

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (USD $)	3 Months Ended		4 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	31-May-13
The carrying amounts and classification of assets and liabilities included in our Consolidated Balance Sheets for these consolidated entities are as follows:	'	'	'	'
Current assets	$6,291.30	'	$6,291.30	$6,880.50
Current liabilities	1,302.30	'	1,302.30	1,764.90
Net sales	1,908.70	2,645.70	2,584.30	'
Variable Interest Entity Primary Beneficiary [Member]	'	'	'	'
The carrying amounts and classification of assets and liabilities included in our Consolidated Balance Sheets for these consolidated entities are as follows:	'	'	'	'
Current assets	49.9	'	49.9	180.7
Non current assets	45.2	'	45.2	46.9
Total assets	95.1	'	95.1	227.6
Current liabilities	10.2	'	10.2	5.4
Total liabilities	10.2	'	10.2	5.4
Variable Interest Entity Phos Chem [Member]	'	'	'	'
The carrying amounts and classification of assets and liabilities included in our Consolidated Balance Sheets for these consolidated entities are as follows:	'	'	'	'
Net sales	$228	$323.30	'	'

Contingencies_Details

Contingencies (Details) (USD $)	Sep. 30, 2013	31-May-13	Sep. 30, 2013	31-May-13	Sep. 30, 2013	Sep. 30, 2013
In Millions, unless otherwise specified			Brazilian Non Income Tax Proceedings [Member]	Asset Retirement Obligation Gypstack [Member]	Positive Outcome of Litigation [Member]	P I S And Cofins Cases [Member]
						Brazilian Non Income Tax Proceedings [Member]
Applicability Impact And Conclusion Of Environmental Loss Contingencies [Abstract]	'	'	'	'	'	'
Accrual For Environmental Loss Contingencies	$23.70	$24.70	'	'	'	'
Loss Contingencies [Line Items]	'	'	'	'	'	'
Asset Retirement Obligation	'	'	'	450	'	'
Asset Retirement Obligations, Undiscounted	'	'	'	1,500	'	'
Future capital expenditures	'	'	'	'	150	'
Amount of cash potentially held in the form of cash escrow or trust fund in the context of a settlement of Government enforcement action	625	'	'	'	'	'
Loss Contingency Estimate Of Possible Loss	'	'	96	'	'	52
Loss Contingency Estimate Of Possible Loss, Net Of Deposits	'	'	$94	'	'	'

Accounting_for_Derivative_Inst2

Accounting for Derivative Instruments and Hedging Activities (Details) (USD $)	Sep. 30, 2013	31-May-13
In Millions, unless otherwise specified
Foreign currency [Member]	'	'
Derivative Instrument	'	'
Monetary Derivative Notional Amount	$944	$1,459.70
Commodity (MMBTU) [Member]	'	'
Derivative Instrument	'	'
Nonmonetary Derivative Notional Amount	10,600,000	15,200,000
Freight Contracts (Tonnes) [Member]	'	'
Derivative Instrument	'	'
Nonmonetary Derivative Notional Amount	800,000	1,500,000
Interest Rate Swap [Member]	'	'
Derivative Instrument	'	'
Monetary Derivative Notional Amount	1,500	'
Interest Rate Swap [Member] | Ten Year Interest Rate Contract [Member]	'	'
Derivative Instrument	'	'
Monetary Derivative Notional Amount	1,250	'
Interest Rate Swap [Member] | Thirty Year Interest Rate Contract [Member]	'	'
Derivative Instrument	'	'
Monetary Derivative Notional Amount	$250	'

Accounting_for_Derivative_Inst3

Accounting for Derivative Instruments and Hedging Activities (Details 2) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Foreign currency [Member] | Cost of goods sold [Member]	'	'
Derivative Gain Loss On Derivative Net [Abstract]	'	'
Derivative Gain Loss On Derivative Net	$22.60	$17.70
Foreign currency [Member] | Foreign currency transaction gain (loss) [Member]	'	'
Derivative Gain Loss On Derivative Net [Abstract]	'	'
Derivative Gain Loss On Derivative Net	-1	0.5
Commodity (MMBTU) [Member] | Cost of goods sold [Member]	'	'
Derivative Gain Loss On Derivative Net [Abstract]	'	'
Derivative Gain Loss On Derivative Net	2.7	5.9
Freight Contracts [Member] | Cost of goods sold [Member]	'	'
Derivative Gain Loss On Derivative Net [Abstract]	'	'
Derivative Gain Loss On Derivative Net	($1.10)	$0.20

Accounting_for_Derivative_Inst4

Accounting for Derivative Instruments and Hedging Activities (Details 3) (USD $)	Sep. 30, 2013	31-May-13
In Millions, unless otherwise specified
Derivative Instruments Fair Value Assets [Abstract]	'	'
Total fair value of derivative assets	$13.20	$17.40
Derivative Instruments Fair Value Liabilities [Abstract]	'	'
Total fair value of derivative liabilities (Negated)	-23.7	-45.1
Foreign currency [Member] | Other Current Assets [Member]	'	'
Derivative Instruments Fair Value Assets [Abstract]	'	'
Total fair value of derivative assets	8.1	10.7
Foreign currency [Member] | Accrued liabilities [Member]	'	'
Derivative Instruments Fair Value Liabilities [Abstract]	'	'
Total fair value of derivative liabilities (Negated)	-16.4	-38.6
Commodity (MMBTU) [Member] | Other Current Assets [Member]	'	'
Derivative Instruments Fair Value Assets [Abstract]	'	'
Total fair value of derivative assets	3.2	4.8
Commodity (MMBTU) [Member] | Other assets [Member]	'	'
Derivative Instruments Fair Value Assets [Abstract]	'	'
Total fair value of derivative assets	0	0.2
Commodity (MMBTU) [Member] | Accrued liabilities [Member]	'	'
Derivative Instruments Fair Value Liabilities [Abstract]	'	'
Total fair value of derivative liabilities (Negated)	-6.7	-6.1
Commodity (MMBTU) [Member] | Other Noncurrent Liabilities [Member]	'	'
Derivative Instruments Fair Value Liabilities [Abstract]	'	'
Total fair value of derivative liabilities (Negated)	-0.5	0
Freight Contracts [Member] | Other Current Assets [Member]	'	'
Derivative Instruments Fair Value Assets [Abstract]	'	'
Total fair value of derivative assets	1.9	1.7
Freight Contracts [Member] | Accrued liabilities [Member]	'	'
Derivative Instruments Fair Value Liabilities [Abstract]	'	'
Total fair value of derivative liabilities (Negated)	($0.10)	($0.40)

Accounting_for_Derivative_Inst5

Accounting for Derivative Instruments and Hedging Activities (Details 4) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Interest Rate Cash Flow Hedge Derivative At Fair Value Net [Abstract]	'
Interest Rate Cash Flow Hedge Asset At Fair Value	$7.30
Interest Rate Cash Flow Hedge Liability At Fair Value	9.2
Interest Rate Cash Flow Hedge Derivative At Fair Value, Net	1.9
Derivative Credit Risk Related Contingent Features [Abstract]	'
Derivative Credit Risk Related Contingent Features Existence And Nature	'Certain of our derivative instruments contain provisions that are governed by International Swap and Derivatives Association (“ISDA”) agreements with the counterparties. These agreements contain provisions that allow us to settle for the net amount between payments and receipts, and also state that if our debt were to be rated below investment grade, certain counterparties could request full collateralization on derivative instruments in net liability positions.
The aggregate fair value of all derivative instruments with credit-risk-related contingent features that were in a liability position	18.8
Required collateral assets to be posted if the credit-risk contingent features of these underlying agreements were triggered.	$16.20

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Sep. 30, 2013	31-May-13
In Millions, unless otherwise specified
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	$13.20	$17.40
Total fair value of derivative liabilities	23.7	45.1
Level 1 [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	1	'
Total fair value of derivative liabilities	3.7	'
Level 1 [Member] | Foreign currency [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	1	'
Total fair value of derivative liabilities	3.7	'
Level 1 [Member] | Commodity (MMBTU) [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	0	'
Total fair value of derivative liabilities	0	'
Level 1 [Member] | Freight Contracts [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	0	'
Total fair value of derivative liabilities	0	'
Level 2 [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	10.3	'
Total fair value of derivative liabilities	19.9	'
Level 2 [Member] | Foreign currency [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	7.1	'
Total fair value of derivative liabilities	12.7	'
Level 2 [Member] | Commodity (MMBTU) [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	3.2	'
Total fair value of derivative liabilities	7.2	'
Level 2 [Member] | Freight Contracts [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	0	'
Total fair value of derivative liabilities	0	'
Level 3 [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	1.9	'
Total fair value of derivative liabilities	0.1	'
Level 3 [Member] | Foreign currency [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	0	'
Total fair value of derivative liabilities	0	'
Level 3 [Member] | Commodity (MMBTU) [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	0	'
Total fair value of derivative liabilities	0	'
Level 3 [Member] | Freight Contracts [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]	'	'
Total fair value of derivative assets	1.9	'
Total fair value of derivative liabilities	$0.10	'

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details 2) (USD $)	Sep. 30, 2013	Jun. 30, 2013	31-May-13	Sep. 30, 2012	Jun. 30, 2012
In Millions, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Cash and cash equivalents	$3,338.60	$3,915.50	$3,697.10	$3,548.50	$3,656.20
Receivables, net	478.7	'	1,015.70	'	'
Accounts payable	611.7	'	763.1	'	'
Short-term debt	14.5	'	68.7	'	'
Carrying (Reported) Amount, Fair Value Disclosure [Member]	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Cash and cash equivalents	3,338.60	'	3,697.10	'	'
Receivables, net	478.7	'	1,015.70	'	'
Accounts payable	611.7	'	763.1	'	'
Short-term debt	14.5	'	68.7	'	'
Long-term debt including current portion	1,012.30	'	1,010.50	'	'
Portion at Fair Value, Fair Value Disclosure [Member]	'	'	'	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'
Cash and cash equivalents	3,338.60	'	3,697.10	'	'
Receivables, net	478.7	'	1,015.70	'	'
Accounts payable	611.7	'	763.1	'	'
Short-term debt	14.5	'	68.7	'	'
Long-term debt including current portion	$1,032.80	'	$1,093.30	'	'

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	Sep. 30, 2013	31-May-13	Sep. 30, 2013	Sep. 30, 2012
In Millions, unless otherwise specified			Nonconsolidated companies [Member]	Nonconsolidated companies [Member]
Related Party Transaction [Line Items]	'	'	'	'
Transactions included in net sales	'	'	$191.80	$248.20
Transactions included in cost of goods sold	'	'	76.1	141.2
Related Party Transactions Paragraph Details [Abstract]	'	'	'	'
Net amount due from our nonconsolidated companies	$23.60	$145.80	'	'

Business_Segments_Details

Business Segments (Details) (USD $)	3 Months Ended		4 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Segment Reporting Information [Line Items]	'	'	'
Net sales	$1,908.70	$2,645.70	$2,584.30
Gross margin	386.9	774.6	506.8
Operating earnings	144.1	643.7	237.9
Capital expenditures	332.5	384.6	'
Depreciation, depletion and amortization	166.1	140.6	'
Operating Segments [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales, external or intersegment	1,908.70	2,645.70	'
Intersegment Elimination [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales, external or intersegment	0	0	'
Phosphates Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	1,418.80	1,740.60	'
Gross margin	193.3	328.9	'
Operating earnings	57.6	246.2	'
Capital expenditures	119.9	99.7	'
Depreciation, depletion and amortization	75.6	70.1	'
Phosphates Segment [Member] | Operating Segments [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales, external or intersegment	1,418.80	1,740.60	'
Phosphates Segment [Member] | Intersegment Elimination [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales, external or intersegment	0	0	'
Potash Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	523.2	927.1	'
Gross margin	184.4	440.9	'
Operating earnings	91.8	398.1	'
Capital expenditures	199.2	263.9	'
Depreciation, depletion and amortization	85.5	67.1	'
Potash Segment [Member] | Operating Segments [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales, external or intersegment	488.5	902.5	'
Potash Segment [Member] | Intersegment Elimination [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales, external or intersegment	34.7	24.6	'
Corporate Eliminations And Other Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales	-33.3	-22	'
Gross margin	9.2	4.8	'
Operating earnings	-5.3	-0.6	'
Capital expenditures	13.4	21	'
Depreciation, depletion and amortization	5	3.4	'
Corporate Eliminations And Other Segment [Member] | Operating Segments [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales, external or intersegment	1.4	2.6	'
Corporate Eliminations And Other Segment [Member] | Intersegment Elimination [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net sales, external or intersegment	($34.70)	($24.60)	'

Investment_in_a_Joint_Venture_

Investment in a Joint Venture (Details) (USD $)	3 Months Ended
	Sep. 30, 2013
	t
Investment in a Joint Venture [Abstract]	'
Cash investment to date	$156,000,000
Investment in phosphates greenfield mine	7,000,000,000
Annual production of finished product (Tonnes)	3,500,000
Percent of joint venture production Mosaic expects to market	25.00%
Economic interest in joint venture	25.00%
Maximum Payments To Acquire Interest In Joint Venture	$1,000,000,000

Assets_Held_For_Sale_Details

Assets Held For Sale (Details) (USD $)	3 Months Ended		4 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	31-May-13
Long Lived Assets Held For Sale [Line Items]	'	'	'	'
Loss on write down of assets	$122.80	$0	$122.80	'
Assets held for sale	232.6	'	232.6	0
Related accrued liabilities held for sale	45.9	'	45.9	'
Argentina And Chile [Member]	'	'	'	'
Long Lived Assets Held For Sale [Line Items]	'	'	'	'
Loss on write down of assets	50	'	'	'
Hersey Mine [Member]	'	'	'	'
Long Lived Assets Held For Sale [Line Items]	'	'	'	'
Loss on write down of assets	48	'	'	'
Related Tax Benefit	$17	'	'	'

Subsequent_Event_Details

Subsequent Event (Details) (USD $)	3 Months Ended		4 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Subsequent Event [Line Items]	'	'	'
Loss on write down of assets	$122.80	$0	$122.80
Subsequent Events Date	28-Oct-13	'	'
Inventories At Price Tied To Natural Gas [Member]	'	'	'
Long Term Purchase Commitment [Line Items]	'	'	'
Purchase Agreement with CF Industries, Inc.	'Under one of the agreements, we will purchase approximately 545,000 to 725,000 tonnes annually for up to fifteen years at a price tied to the prevailing price of U.S. natural gas. This agreement is expected to commence prior to January 1, 2017.	'	'
Long Term Purchase Commitment Minimum Quantity Required	545,000	'	'
Long Term Purchase Commitment Maximum Quantity Required	725,000	'	'
Long Term Purchase Commitment Time Period	'annually for up to fifteen years at a price tied to the prevailing price of U.S. natural gas. This agreement is expected to commence prior to January 1, 2017	'	'
Inventories At Price Tied To C F R Tampa Price [Member]	'	'	'
Long Term Purchase Commitment [Line Items]	'	'	'
Purchase Agreement with CF Industries, Inc.	'Under a second agreement, we would purchase approximately 270,000 tonnes annually for three years from CF’s Trinidad operations at CFR Tampa market-based pricing.	'	'
Long Term Purchase Commitment Minimum Quantity Required	270,000	'	'
Long Term Purchase Commitment Time Period	'annually for three years	'	'
New Ammonia Plant [Member]	'	'	'
Subsequent Event [Line Items]	'	'	'
Loss on write down of assets	25	'	'
Related Tax Benefit	9	'	'
C F Florida Phosphates Assets [Member]	'	'	'
Subsequent Event [Line Items]	'	'	'
Significant Acquisitions And Disposals Acquisition Costs Or Sale Proceeds	1,200	'	1,200
C F Asset Retirement Obligations [Member]	'	'	'
Subsequent Event [Line Items]	'	'	'
Significant Acquisitions And Disposals Acquisition Costs Or Sale Proceeds	$200	'	$200

Additional_Financial_Informati2

Additional Financial Information (Details) (USD $)	3 Months Ended		4 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Condensed Consolidated Statement of Earnings (Unaudited) [Abstract]	'	'	'
Net sales	$1,908.70	$2,645.70	$2,584.30
Cost of goods sold	1,521.80	1,871.10	2,077.50
Gross margin	386.9	774.6	506.8
Selling, general and administrative expenses	94.4	114.8	120.6
Loss on write down of assets	122.8	0	122.8
Other operating expense (income)	25.6	16.1	25.5
Operating earnings	144.1	643.7	237.9
Interest income (expense), net	1.8	5.1	-1.3
Foreign currency transaction gain (loss)	-29.6	-27.3	-8.6
Other (expense) income	0.4	-0.6	0.2
Earnings from consolidated companies before income taxes	116.7	620.9	228.2
Provision for (benefit from) income taxes	-6.6	189	21.4
Earnings from consolidated companies	123.3	431.9	206.8
Equity in net earnings (loss) of nonconsolidated companies	2.5	-12.9	6
Net earnings including noncontrolling interests	125.8	419	212.8
Less: Net earnings (loss) attributable to noncontolling interests	1.4	1.6	1.8
Net earnings attributable to Mosaic	124.4	417.4	211
Statement Of Cash Flows Abstract	'	'	'
Net cash provided by (used in) operating activities	-45	343.8	388.9
Net cash (used in) provided by investing activities	-465.7	-375.5	-603.2
Net cash (used in) financing activities	($89.50)	($102.90)	($136.20)