Significant Accounting Policies (Details 2) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Finite Lived Intangible Assets
Research, development and related expenses	$ 438	$ 448	$ 901	$ 900
Deferred tax assets valuation allowance	$ 22		$ 22		$ 22

The aggregate costs incurred during an accounting period to research and develop new products/technologies when the technological feasibility has not been reached, and related expenses, which primarily include technical support provided by 3M to customers who are using existing 3M products; internally developed patent costs, which include costs and fees incurred to prepare, file, secure and maintain patents; and amortization of acquired patents.

No definition available.

Name:	mmm_ResearchDevelopmentAndRelatedExpenses
Namespace Prefix:	mmm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration