Stock-Based Compensation (Details 2) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Stock Option Program	Sep. 30, 2013 Stock Option Program	Sep. 30, 2014 Stock Option Program Maximum	Sep. 30, 2014 Stock Option Program Minimum	Sep. 30, 2014 Stock Option Program Annual Stock Option Program	Sep. 30, 2014 3M Long Term Incentive Plan	May 31, 2012 3M Long Term Incentive Plan
Stock Option Program
Balance at the beginning of the period					43,938,778
Granted - Annual					5,736,183
Exercised					(7,765,197)
Canceled					(189,110)
Balance at the end of the period					41,720,654
Weighted average exercise price - Beginning balance					$ 83.84
Weighted average exercise price - Granted - Annual					$ 126.77
Weighted average exercise price - Exercised					$ 82.63
Weighted average exercise price - Canceled					$ 104.46
Weighted average exercise price - Ending balance					$ 89.88
Vesting period							3 years	1 year
Expiration of annual grants					10 years
Options exercisable					29,955,673
Options exercisable, exercise price					$ 81.43
Weighted average remaining contractual life for options outstanding					66 months
Aggregate intrinsic value for options outstanding					$ 2,161
Weighted average remaining contractual life for options exercisable					51 months
Aggregate intrinsic value for options exercisable					1,805
Compensation expense yet to be recognized					73
Weighted average life of remaining vesting period					23 months
Total intrinsic value of stock options exercised					437	444
Cash received from options exercised					642	1,282
Tax benefit realized from exercise of stock options					161	164
Share- based compensation assumptions
Weighted average exercise price									$ 126.72
Risk-free interest rate (as a percent)									1.90%
Dividend yield (as a percent)									2.60%
Expected volatility (as a percent)									20.80%
Expected life									75 months
Black-Scholes fair value									$ 19.63
Stock-based compensation programs expense	$ 47	$ 47	$ 221	$ 197
Number of shares authorized											100,000,000
Number of shares available for grant under the 2008 Long Term Incentive Plan Program (including additional subsequent shareholder approvals)										29,004,028