Pension and Postretirement Benefit Plans (Details 7) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
U.S. Defined Contribution Plan
Schedule Of Defined Contribution Plans Disclosures
Company match of eligible compensation, high end of range	6.00%
Employer match of employee contributions, pre January 1, 2009, low end of range	60.00%
Employer match of employee contributions, pre January 1, 2009, high end of range	75.00%
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	$ 124	$ 109	$ 97
Foreign Defined Contribution Plan
Schedule Of Defined Contribution Plans Disclosures
Expenses related to defined contribution plans	$ 58	$ 54	$ 36

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

No definition available.

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	mmm_DefinedContributionPlanEmployerMatchHighEndOfRange
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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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
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- Details

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Data Type:	xbrli:stringItemType
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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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 11

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration