Document And Entity Information	6 Months Ended
	Jan. 31, 2015	Feb. 28, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jan. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2
Entity Registrant Name	DONALDSON CO INC
Entity Central Index Key	0000029644
Current Fiscal Year End Date	--07-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		136,545,705