Consolidated Statement of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Net sales	$ 8,942	$ 8,350	$ 26,743	$ 23,601
Operating expenses
Cost of sales	4,853	4,303	14,097	12,217
Selling, general and administrative expenses	1,819	1,677	5,373	5,039
Research, development and related expenses	482	461	1,520	1,422
Gain on sale of businesses	0	0	0	(389)
Total operating expenses	7,154	6,441	20,990	18,289
Operating income	1,788	1,909	5,753	5,312
Other expense (income), net	31	83	113	248
Income before income taxes	1,757	1,826	5,640	5,064
Provision for income taxes	324	391	1,058	1,016
Income of consolidated group	1,433	1,435	4,582	4,048
Income (loss) from unconsolidated subsidiaries, net of taxes	4	(1)	7	(1)
Net income including noncontrolling interest	1,437	1,434	4,589	4,047
Less: Net income (loss) attributable to noncontrolling interest	3	4	7	3
Net income attributable to 3M	$ 1,434	$ 1,430	$ 4,582	$ 4,044
Weighted average 3M common shares outstanding - basic (in shares)	579.6	577.8	580.3	577.2
Earnings per share attributable to 3M common shareholders - basic (in dollars per share)	$ 2.47	$ 2.47	$ 7.90	$ 7.01
Weighted average 3M common shares outstanding - diluted (in shares)	586.3	582.4	587.1	581.6
Earnings per share attributable to 3M common shareholders - diluted (in dollars per share)	$ 2.45	$ 2.45	$ 7.81	$ 6.95