This element represents the Company match for all eligible compensation for defined contribution plans.

No definition available.

Name:	mmm_CompanyMatchOfEligibleCompensationForCompanyDefinedContributionPlans
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

- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

+ Details

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

+ References

No definition available.

+ Details

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

- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RetirementPlanSponsorLocationAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanSponsorLocationAxis=us-gaap_ForeignPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Pension and Postretirement Benefit Plans - Opening Paragraph Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
United States
Schedule Of Defined Contribution Plans Disclosures
Company match of eligible compensation of employee contributions into 401(k)	5.00%
Company cash match of employee contributions for employees hired 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	$ 201	$ 186	$ 173
International
Schedule Of Defined Contribution Plans Disclosures
Expenses related to defined contribution plans	$ 103	$ 96	$ 99
Maximum \| United States
Schedule Of Defined Contribution Plans Disclosures
Company cash match of employee contributions for employees hired prior to January 1, 2009	60.00%
Minimum \| United States
Schedule Of Defined Contribution Plans Disclosures
Company cash match of employee contributions for employees hired prior to January 1, 2009	45.00%