Major acquisitions and disposals (Details 2) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2010 Vale Fertilizantes S.A	Dec. 31, 2010 Vale Fosfatados	Dec. 31, 2011 Northern Energy S.A. USD ($)	Dec. 31, 2011 Northern Energy S.A. BRL	Dec. 31, 2011 Fertilizers Businesses USD ($)
Business acquisition
Business acquisition percentage of total capital acquired	78.92%	100.00%	9.00%	9.00%
Voting capital acquired (as a percent)	99.83%
Total estimated investment			$ 1,200	2,300
Amount invested for business acquisition			84
Purchase price			$ 70		$ 5,795

Percentage of voting equity interests acquired in the business combination.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6909870&loc=d3e1392-128463

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