Document and Entity Information	3 Months Ended
	Mar. 31, 2016 shares
Document and Entity Information
Entity Registrant Name	ECOLAB INC.
Entity Central Index Key	0000031462
Document Type	10-Q
Document Period End Date	Mar. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding	293,305,223
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q1