Represents the employee contributions (percentage of compensation) which are matched by the employer.

No definition available.

Name:	mmm_DefinedContributionPlanEmployerMatchEmployeeContribution
Namespace Prefix:	mmm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the employer matching contribution of the employee contributions for employees hired after January 1, 2009.

+ References

No definition available.

+ Details

Name:	mmm_DefinedContributionPlanEmployerMatchHiredAfter2009
Namespace Prefix:	mmm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the employer matching contribution of the employee contributions for employees hired prior to January 1, 2009.

+ References

No definition available.

+ Details

Name:	mmm_DefinedContributionPlanEmployerMatchHiredBefore2009
Namespace Prefix:	mmm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

For a defined contribution postretirement plan, the percentage of eligible compensation which the entity will contribute for employees hired after January 1, 2009.

+ References

No definition available.

+ Details

Name:	mmm_DefinedContributionPlanPostretirementPlanHiredAfter2009Percentage
Namespace Prefix:	mmm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	mmm_ScheduleOfDefinedContributionPlansDisclosuresLineItems
Namespace Prefix:	mmm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

+ Details

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	mmm_DefinedContributionPlanByGeographyAxis=mmm_DefinedContributionPlanForeignMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	mmm_DefinedContributionPlanByGeographyAxis=mmm_DefinedContributionPlanUSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Pension and Postretirement Benefit Plans (Narratives) (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
U.S. Defined Contribution Plan
Schedule Of Defined Contribution Plans Disclosures
Company match of eligible compensation, high end of range	6.00%
Company match of eligible compensation, percent for employees hired on or after January 1, 2009	100.00%
Company contribution to employer retirement income account for employees hired on or after January 1, 2009	3.00%
Expenses related to defined contribution plans	$ 153	$ 136	$ 124
U.S. Defined Contribution Plan \| Maximum
Schedule Of Defined Contribution Plans Disclosures
Employer match of employee contributions, pre January 1, 2009	75.00%
U.S. Defined Contribution Plan \| Minimum
Schedule Of Defined Contribution Plans Disclosures
Employer match of employee contributions, pre January 1, 2009	60.00%
Foreign Defined Contribution Plan
Schedule Of Defined Contribution Plans Disclosures
Expenses related to defined contribution plans	$ 75	$ 71	$ 58