Supplemental Equity and Comprehensive Income Information (Details 5) In Millions, unless otherwise specified	3 Months Ended									12 Months Ended			3 Months Ended	6 Months Ended
	Dec. 31, 2011 USD ($)	Sep. 30, 2011 USD ($)	Jun. 30, 2011 USD ($)	Mar. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Sep. 30, 2010 USD ($)	Jun. 30, 2010 USD ($)	Mar. 31, 2010 USD ($)	Mar. 31, 2010 JPY (¥)	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Mar. 31, 2010 Sumitomo 3M Limited JPY (¥)	Dec. 31, 2009 Sumitomo 3M Limited USD ($)
Transactions with Sumitomo 3M
3M's effective ownership before transaction (as a percent)													71.50%	75.00%
3M's effective ownership after transaction (as a percent)													75.00%	71.50%
Increase in noncontrolling interest														$ 81
Cash paid to acquire additional shares								63	5,800
Note payable issued to Sumitomo Electric Industries								188	17,400				17,400
Purchase of subsidiary shares including other transfers from noncontrolling interest								278
Net income attributable to 3M	954	1,088	1,160	1,081	928	1,106	1,121	930		4,283	4,085	3,193
Transfer from noncontrolling interest							24	22			43	(81)
Change in 3M Company shareholders' equity from net income attributable to 3M and transfers from noncontrolling interest											$ 4,128	$ 3,112