Significant Accounting Policies (Details) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014 USD ($)	Mar. 31, 2013 USD ($)	Dec. 31, 2013	Mar. 31, 2014 VEF
Foreign Currency Translation
Threshold percentage used to determine if economic environment is highly inflationary	100.00%
Number of years used to determine if economic environment is highly inflationary	3 years
Operating income of Venezuelan subsidiary as percent of consolidated amount high end of range			1.00%
Cumulative inflation rate of Venezuela in November 2009 and since, low end of range	100.00%
Maximum balance of company's net monetary liabilities in Venezuelan bolivars				135
Exchange rate established by Venezuelan government from bolivars to dollars - SICAD1				11
Exchange rate established by Venezuelan government from bolivars to dollars - SICAD2				50
Earnings per share
Options outstanding not included in computation of diluted earnings per share (in shares)	2.3	4.1
Numerator:
Net income attributable to 3M	$ 1,207	$ 1,129
Denominator:
Denominator for weighted average 3M common shares outstanding - basic (in shares)	661.5	691.1
Dilution associated with the Company's stock-based compensation plans (in shares)	13.0	11.0
Denominator for weighted average 3M common shares outstanding - diluted (in shares)	674.5	702.1
Earnings per share attributable to 3M common shareholders - basic (in dollars per share)	$ 1.83	$ 1.63
Earnings per share attributable to 3M common shareholders - diluted (in dollars per share)	$ 1.79	$ 1.61