Supplemental Equity and Comprehensive Income Information (Details 4) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended			1 Months Ended	9 Months Ended			1 Months Ended
	Sep. 30, 2014 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	Sep. 30, 2014 Common Stock and Additional Paid-in Capital USD ($)	Sep. 30, 2014 Common Stock and Additional Paid-in Capital USD ($)	Sep. 30, 2013 Common Stock and Additional Paid-in Capital USD ($)	Sep. 30, 2014 Noncontrolling Interest USD ($)	Sep. 30, 2014 Noncontrolling Interest USD ($)	Sep. 30, 2013 Noncontrolling Interest USD ($)	Mar. 31, 2013 3M India Limited	Sep. 30, 2014 Sumitomo 3M Limited USD ($)	Sep. 30, 2014 Sumitomo 3M Limited USD ($)	Sep. 30, 2014 Sumitomo 3M Limited JPY (¥)	Jul. 31, 2014 Sumitomo 3M Limited	Sep. 30, 2014 Sumitomo 3M Limited Noncontrolling Interest USD ($)
Transactions with 3M subsidiaries that have non controlling interests
3M's effective ownership before transaction (as a percent)										76.00%
3M's effective ownership after transaction (as a percent)										75.00%	100.00%	100.00%	100.00%
Minimum percentage of public shareholding required by an amendment to Indian Securities regulations to comply with the sale of shares for 3M India Limited										25.00%
Sale of subsidiary shares			$ 8			$ 7			$ 1
Percent of interest acquired of Sumitomo 3M Limited														25.00%
Purchase of remaining noncontrolling interest portion	865	870		433	434		457	461			865		90,000		457
Amount recorded as a financing activity in the statement of cash flows												$ 694