Pension and Postretirement Benefit Plans (Narratives) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				3 Months Ended
	Mar. 31, 2012	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2011 LimitedPartner	Mar. 31, 2013 Qualified and Non-qualified Pension Benefits	Mar. 31, 2013 Postretirement Benefits
Benefit Plan Information
Contributions made to the Company's plans					$ 67	$ 1
Estimated pension and postretirement employer contributions in current fiscal year, low end of range		400
Estimated pension and postretirement employer contributions in current fiscal year, high end of range		600
Number of additional limited partners of WG Trading Company, in addition to 3M, who objected and appealed the court's order to the United States Court of Appeals for the Second Circuit				6
Percentage of WG Trading Company holdings in relation to total fair value of the company's total plan assets, high end of range (as a percent)			1.00%
Special termination benefits - number of additional years of pension service	1 year
Special termination benefits - number of additional years of age for certain benefit calculations	1 year
Special termination benefits - number of participants	616
Special termination benefits charge	$ 26