Significant Accounting Policies (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Earnings per share
Options outstanding not included in computation of diluted earnings per share (in shares)	19.2	3.6
Numerator:
Net income attributable to 3M	$ 1,125	$ 1,081
Denominator:
Denominator for weighted average 3M common shares outstanding - basic (in shares)	696.8	711.5
Dilution associated with the Company's stock-based compensation plans (in shares)	9.3	14.9
Denominator for weighted average 3M common shares outstanding - diluted (in shares)	706.1	726.4
Earnings per share attributable to 3M common shareholders - basic (in dollars per share)	$ 1.61	$ 1.52
Earnings per share attributable to 3M common shareholders - diluted (in dollars per share)	$ 1.59	$ 1.49
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