Stock-Based Compensation (Details)	3 Months Ended
Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award Activity
Retirement age eligibility for employees	55 years
Retirement eligibility for employees, minimum years of service required	5 years
Percent of stock-based compensation related to retiree-eligible population (as a percent)	35.00%
3M Long Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award Activity
Number of shares authorized	100,000,000
Number of shares available for grant under the 2008 Long Term Incentive Plan Program (including additional subsequent shareholder approvals)	19,593,667

Percent of stock-based compensation related to retiree-eligible population.

No definition available.

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

- Definition

The age at which employees of the entity are eligible for retirement, which combined with reaching years of service triggers expense recognition of share based compensation expense, in years.

+ References

No definition available.

+ Details

Name:	mmm_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpenseRecognitionEligibleForRetirementAge
Namespace Prefix:	mmm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of years of service which combined with reaching eligible retirement age triggers expense recognition of share based compensation expense, in years.

+ References

No definition available.

+ Details

Name:	mmm_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpenseRecognitionYearsOfServiceNumber
Namespace Prefix:	mmm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_AwardTypeAxis=mmm_LongTermIncentivePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: