Earnings Per Share - Computations for Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Numerator:
Net income from continuing operations attributable to 3M	$ 834	$ 1,372	$ 2,673	$ 3,281
Net income from discontinued operations, net of taxes	0	0	0	164
Net income attributable to 3M	$ 834	$ 1,372	$ 2,673	$ 3,445
Denominator:
Weighted average 3M common shares outstanding - basic (in shares)	534.1	550.6	538.4	553.1
Dilution associated with stock-based compensation plans (in shares)	4.0	2.1	3.7	1.4
Weighted average 3M common shares outstanding – diluted (in shares)	538.1	552.7	542.1	554.5
Earnings per share attributable to 3M common shareholders:
Earnings per share from continuing operations — basic (in dollars per share)	$ 1.56	$ 2.49	$ 4.97	$ 5.93
Earnings per share from discontinued operations — basic (in dollars per share)	0	0	0	0.30
Earnings per share — basic (in dollars per share)	1.56	2.49	4.97	6.23
Earnings per share from continuing operations — diluted (in dollars per share)	1.55	2.48	4.93	5.92
Earnings per share from discontinued operations — diluted (in dollars per share)	0	0	0	0.29
Earnings per share — diluted (in dollars per share)	$ 1.55	$ 2.48	$ 4.93	$ 6.21