Significant Accounting Policies - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Earnings per share
Options outstanding not included in computation of diluted earnings per share (in shares)	23.1	8.7
Numerator:
Net income attributable to 3M	$ 1,299	$ 1,624
Denominator:
Denominator for weighted average 3M common shares outstanding - basic (in shares)	572.3	580.5
Dilution associated with the Company's stock-based compensation plans (in shares)	2.7	5.8
Denominator for weighted average 3M common shares outstanding - diluted (in shares)	575.0	586.3
Earnings per share attributable to 3M common shareholders - basic (in dollars per share)	$ 2.27	$ 2.80
Earnings per share attributable to 3M common shareholders - diluted (in dollars per share)	$ 2.26	$ 2.77