Summary of significant accounting policies (Details 2) (Fertilizers)	12 Months Ended
Dec. 31, 2012 group
Fertilizers
Segment Reporting Information
Number of major groups of nutrients	3

Represents the number of major groups of nutrients.

No definition available.

Name:	vale_NumberOfMajorGroupsOfNutrients
Namespace Prefix:	vale_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration