Consolidated Statement of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Consolidated Statement of Income
Net sales	$ 32,184	$ 32,136	$ 32,765
Operating expenses
Cost of sales	16,605	17,136	16,682
Selling, general and administrative expenses	6,929	7,029	7,602
Research, development and related expenses	1,878	1,911	1,821
Gain on sale of businesses	(389)	(114)	(547)
Total operating expenses	25,023	25,962	25,558
Operating income	7,161	6,174	7,207
Interest expense and income
Other expense (income), net	450	462	207
Income before income taxes	6,711	5,712	7,000
Provision for income taxes	1,318	1,130	1,637
Income of consolidated group	5,393	4,582	5,363
Income (loss) from unconsolidated subsidiaries, net of taxes	(5)
Net income including noncontrolling interest	5,388	4,582	5,363
Less: Net income (loss) attributable to noncontrolling interest	4	12	14
Net income attributable to 3M	$ 5,384	$ 4,570	$ 5,349
Weighted average 3M common shares outstanding - basic (in shares)	577.6	577.0	588.5
Earnings per share attributable to 3M common shareholders - basic (in dollars per share)	$ 9.32	$ 7.92	$ 9.09
Weighted average 3M common shares outstanding - diluted (in shares)	582.2	585.1	602.0
Earnings per share attributable to 3M common shareholders - diluted (in dollars per share)	$ 9.25	$ 7.81	$ 8.89