Commitments and Contingencies (Details 2) (USD $)	9 Months Ended
Sep. 30, 2011 Claimant Claim Y
Employment Litigation - Whitaker lawsuit
Loss contingencies
Current employees filing lawsuit	1
Former employees filing lawsuit	1
Threshold age for members of class action (in years)	46
Punitive damages, statutory limit per claimant	$ 8,500
Number of additional named plaintiffs	4
Number of claims dismissed and settled	1
Employment Litigation - Garcia lawsuit
Loss contingencies
Current employees filing lawsuit	1
Former employees filing lawsuit	5
Threshold age for members of class action (in years)	46
Total number of named plaintiffs	6
Approximate number of current or former employees who have signed "opt-in" forms	130
Upper end of salary grade level involved in lawsuit	18
Threshold age for federal protection from age discrimination	40
EEOC age-discrimination charges
Loss contingencies
Current employees filing lawsuit	1
Former employees filing lawsuit	6
Number of claimants not involved in Garcia lawsuit	1
EEOC age-discrimination charges \| Minnesota, Texas and California
Loss contingencies
Former employees filing lawsuit	3
EEOC age-discrimination charges \| Minnesota
Loss contingencies
Former employees filing lawsuit	2

The number of additional named plaintiffs to a class action.

Name:	mmm_LossContingencyAdditionalNamedPlaintiffs
Namespace Prefix:	mmm
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of current employees seeking to represent a class in a lawsuit.

+ Details

Name:	mmm_LossContingencyClaimantsCurrentEmployeesNumber
Namespace Prefix:	mmm
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of former employees seeking to represent a class in a lawsuit.

+ Details

Name:	mmm_LossContingencyClaimantsFormerEmployeesNumber
Namespace Prefix:	mmm
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of either current or former employees seeking to join action.

+ Details

Name:	mmm_LossContingencyClaimantsSeekingToJoinActionNumber
Namespace Prefix:	mmm
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The threshold age of employees to be members of the class engaged in a lawsuit.

+ Details

Name:	mmm_LossContingencyClassOfCurrentAndFormerEmployeesThresholdAge
Namespace Prefix:	mmm
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The threshold age of employees protected from age discrimination by federal law.

+ Details

Name:	mmm_LossContingencyFederalLawProtectionThresholdAge
Namespace Prefix:	mmm
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The statutory limit to punitive damages per claimant.

+ Details

Name:	mmm_LossContingencyPunitiveDamagesLimitPerClaimant
Namespace Prefix:	mmm
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The upper end of the salary grade level involved in the lawsuit.

+ Details

Name:	mmm_LossContingencySalaryGradeUpperEndOfRangeInLawsuit
Namespace Prefix:	mmm
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The total number of named plaintiffs in employment litigation action.

+ Details

Name:	mmm_LossContingencyTotalNamedClaimantsEmploymentLitigation
Namespace Prefix:	mmm
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of claimants in this matter that are not also involved in a separate lawsuit against the entity.

+ Details

Name:	mmm_LossContingencyTotalNamedClaimantsNotNamedInOtherLawsuit
Namespace Prefix:	mmm
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of claims settled and dismissed during the period.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9, 10, 11, 12

-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

Name:	us-gaap_LossContingencyClaimsSettledAndDismissedNumber
Namespace Prefix:	us-gaap
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration