Stock-Based Compensation (Details 2) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Share- based compensation assumptions
Stock-based compensation programs expense	$ 138	$ 122
Stock Option Program
Stock Option Program
Balance at the beginning of the period	39,235,557
Granted - Annual	5,529,615
Exercised	(3,164,169)
Canceled	(25,786)
Balance at the end of the period	41,575,217
Weighted average exercise price - Beginning balance	$ 90.38
Weighted average exercise price - Granted - Annual	$ 165.91
Weighted average exercise price - Exercised	$ 84.03
Weighted average exercise price - Canceled	$ 130.40
Weighted average exercise price - Ending balance	$ 100.89
Expiration of annual grants	10 years
Options exercisable	30,089,556
Options exercisable, exercise price	$ 85.71
Weighted average remaining contractual life for options outstanding	72 months
Aggregate intrinsic value for options outstanding	2,669
Weighted average remaining contractual life for options exercisable	58 months
Aggregate intrinsic value for options exercisable	2,384
Compensation expense yet to be recognized	123
Weighted average life of remaining vesting period	27 months
Total intrinsic value of stock options exercised	258	143
Cash received from options exercised	266	229
Tax benefit realized from exercise of stock options	$ 96	$ 52
Stock Option Program | Maximum
Stock Option Program
Vesting period	3 years
Stock Option Program | Minimum
Stock Option Program
Vesting period	1 year
Stock Option Program | Annual Stock Option Program
Share- based compensation assumptions
Weighted average exercise price	$ 165.94
Risk-free interest rate (as a percent)	1.50%
Dividend yield (as a percent)	2.50%
Expected volatility (as a percent)	20.10%
Expected life	76 months
Black-Scholes fair value	$ 23.98
3M Long Term Incentive Plan
Share- based compensation assumptions
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)	19,593,667