Quarterly Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Data (Unaudited)
Net Sales	$ 7,945	$ 8,152	$ 8,390	$ 8,278	$ 7,990	$ 8,172	$ 7,810	$ 7,685	$ 32,765	$ 31,657	$ 30,109
Cost of sales	4,060	4,159	4,227	4,236	4,094	4,059	4,020	3,882	16,682	16,055	15,118
Net income including noncontrolling interest	1,349	1,546	1,862	606	525	1,433	1,585	1,326	5,363	4,869	5,058
Net income attributable to 3M	$ 1,347	$ 1,543	$ 1,857	$ 602	$ 523	$ 1,429	$ 1,583	$ 1,323	$ 5,349	$ 4,858	$ 5,050
Earnings per share attributable to 3M common shareholders - basic (in dollars per share)	$ 2.32	$ 2.64	$ 3.14	$ 1.01	$ 0.88	$ 2.39	$ 2.65	$ 2.21	$ 9.09	$ 8.13	$ 8.35
Earnings per share attributable to 3M common shareholders - diluted (in dollars per share)	$ 2.27	$ 2.58	$ 3.07	$ 0.98	$ 0.85	$ 2.33	$ 2.58	$ 2.16	$ 8.89	$ 7.93	$ 8.16