Pension and Postretirement Benefit Plans (Narratives) (Details) (USD $)	3 Months Ended				9 Months Ended
	Mar. 31, 2012	Sep. 30, 2012	Dec. 31, 2011	Mar. 31, 2011 LimitedPartner	Sep. 30, 2012 Qualified and Non-qualified Pension Benefits	Sep. 30, 2012 Postretirement Benefits
Benefit Plan Information
Contributions made to the Company's plans					$ 853,000,000	$ 65,000,000
Defined benefit plan estimated current fiscal year employer contributions		1,000,000,000
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	$ 26,000,000