Quarterly Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Quarterly Data (Unaudited)
Net sales	$ 7,686	$ 8,134	$ 15,264	$ 15,965
Cost of sales	3,858	4,184	7,679	8,215
Net income including noncontrolling interest	1,303	1,283	2,504	2,508
Net income attributable to 3M	$ 1,300	$ 1,267	$ 2,499	$ 2,474
Earnings per share attributable to 3M common shareholders - basic (in dollars per share)	$ 2.06	$ 1.94	$ 3.94	$ 3.77
Earnings per share attributable to 3M common shareholders - diluted (in dollars per share)	$ 2.02	$ 1.91	$ 3.87	$ 3.70