Consolidated Statement of Income (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net sales	$ 31,821	$ 30,871	$ 29,904
Operating expenses
Cost of sales	16,447	16,106	15,685
Selling, general and administrative expenses	6,469	6,384	6,102
Research, development and related expenses	1,770	1,715	1,634
Total operating expenses	24,686	24,205	23,421
Operating income	7,135	6,666	6,483
Interest expense and income
Interest expense	142	145	171
Interest income	(33)	(41)	(39)
Total interest expense - net	109	104	132
Income before income taxes	7,026	6,562	6,351
Provision for income taxes	2,028	1,841	1,840
Net income including noncontrolling interest	4,998	4,721	4,511
Less: Net income attributable to noncontrolling interest	42	62	67
Net income attributable to 3M	$ 4,956	$ 4,659	$ 4,444
Weighted average 3M common shares outstanding - basic (in shares)	649.2	681.9	693.9
Earnings per share attributable to 3M common shareholders - basic (in dollars per share)	$ 7.63	$ 6.83	$ 6.40
Weighted average 3M common shares outstanding - diluted (in shares)	662.0	693.6	703.3
Earnings per share attributable to 3M common shareholders - diluted (in dollars per share)	$ 7.49	$ 6.72	$ 6.32
Cash dividends paid per 3M common share (in dollars per share)	$ 3.42	$ 2.54	$ 2.36