Income Taxes (Details 6) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Taxes
Income tax benefits attributable to reduced tax rates or exemptions in foreign locations	$ 64,000,000	$ 77,000,000	$ 69,000,000
EPS impact of reduced tax rates or exemptions in foreign locations (in dollars per diluted share)	$ 0.09	$ 0.11	$ 0.10
Undistributed earnings of non-U.S. subsidiaries	$ 8,600,000,000

The amount as of the balance sheet date of undistributed foreign earnings on which the entity has not provided deferred taxes as these amounts are considered to be indefinitely reinvested.

No definition available.

Name:	mmm_DeferredTaxLiabilityNotRecognizedUndistributedForeignEarnings
Namespace Prefix:	mmm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant