Significant Accounting Policies (Details) (USD $) In Millions, except Per Share data	3 Months Ended				9 Months Ended
	Sep. 30, 2011	Mar. 31, 2011	Sep. 30, 2010	Mar. 31, 2010	Sep. 30, 2011	Sep. 30, 2010
Supplemental Balance Sheet Information
Revision of amounts previously presented related to purchase of additional shares of non-wholly owned consolidated subsidiaries, which increased cash used in financing activities and decreased cash used in investing activities		$ 33		$ 63
Earnings per share
Options outstanding not included in computation of diluted earnings per share (in shares)	29.7		30.2		12.3	30.4
Numerator:
Net income attributable to 3M	$ 1,088		$ 1,106		$ 3,329	$ 3,157
Denominator:
Denominator for weighted average 3M common shares outstanding - basic (in shares)	707.7		714.0		710.9	713.4
Dilution associated with the Company's stock-based compensation plans (in shares)	7.8		11.2		11.9	11.4
Denominator for weighted average 3M common shares outstanding - diluted (in shares)	715.5		725.2		722.8	724.8
Earnings per share attributable to 3M common shareholders - basic (in dollars per share)	$ 1.54		$ 1.55		$ 4.68	$ 4.42
Earnings per share attributable to 3M common shareholders - diluted (in dollars per share)	$ 1.52		$ 1.53		$ 4.61	$ 4.36