Quarterly Data (Unaudited) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Quarterly Data (Unaudited)
Net sales	$ 8,137	$ 7,916	$ 24,102	$ 23,302
Cost of sales	4,205	4,148	12,420	12,130
Net income including noncontrolling interest	1,311	1,245	3,819	3,605
Net income attributable to 3M	$ 1,303	$ 1,230	$ 3,777	$ 3,556
Earnings per share attributable to 3M common shareholders - basic (in dollars per share)	$ 2.02	$ 1.81	$ 5.78	$ 5.18
Earnings per share attributable to 3M common shareholders - diluted (in dollars per share)	$ 1.98	$ 1.78	$ 5.67	$ 5.10