Quarterly Data (Unaudited) (Details) (USD $)
In Millions, except Per Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Quarterly Data (Unaudited)    
Net sales $ 7,578 $ 7,831
Cost of sales 3,821 4,031
Net income including noncontrolling interest 1,201 1,225
Net income attributable to 3M $ 1,199 $ 1,207
Earnings per share attributable to 3M common shareholders - basic (in dollars per share) $ 1.88 $ 1.83
Earnings per share attributable to 3M common shareholders - diluted (in dollars per share) $ 1.85 $ 1.79