Document and Entity Information - USD ($) shares in Millions, $ in Billions	12 Months Ended
	Dec. 31, 2016	Jan. 31, 2017	Jun. 30, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	3M Company
Trading Symbol	mmm
Entity Central Index Key	0000066740
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float		$ 104.2	$ 105.8
Entity Common Stock, Shares Outstanding		596.2
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY