The maximum balance of the Company's overall net monetary assets valued functional currency.

No definition available.

Name:	mmm_BalanceOfCompanyNetMonetaryAssets
Namespace Prefix:	mmm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The denominator used to determine the conversion from the Venezuelan Bolivar to the Sovereign Bolivar.

+ References

No definition available.

+ Details

Name:	mmm_DenominatorForCurrencyConversionFromVenezuelanBolivarToSovereignBolivarForVenezuelanSubsidiary
Namespace Prefix:	mmm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The threshold percentage for determining whether an economic environment is highly inflationary for purposes of determining the functional currency of an entity.

+ References

No definition available.

+ Details

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

- Definition

The number of years used in the calculation to determine whether an economic environment is highly inflationary for purposes of determining the functional currency of an entity.

+ References

No definition available.

+ Details

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

- Definition

The operating income of a subsidiary (located in the highly inflationary country of Venezuela) as a percentage of the consolidated operating income, high end of range.

+ References

No definition available.

+ Details

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

- Definition

Foreign exchange rate used to remeasure amounts denominated in a currency other than functional currency into functional currency.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 30
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6897108&loc=SL6897125-166521

+ Details

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Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109240200&loc=d3e30700-110894

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=109240200&loc=d3e30690-110894

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7)
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=country_AR
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Significant Accounting Policies - Foreign Currency Translation (Details) $ in Millions, $ in Millions	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2018 USD ($) item	Jun. 30, 2018	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2018	Sep. 30, 2019 ARS ($)
Foreign Currency Translation
Pre-tax charge	$ 45		$ 51		$ 349	$ 144
Foreign currency transaction loss	$ 69				$ 190
Venezuela
Foreign Currency Translation
Pre-tax charge		$ 162
Foreign currency transaction loss		$ (144)
Subsidiary \| Venezuela
Foreign Currency Translation
Denominator used to determine conversion from Venezuelan Bolivar to Sovereign Bolivar. \| item			100,000
Subsidiary \| Argentina
Foreign Currency Translation
Threshold percentage used to determine if economic environment is highly inflationary				100.00%
Number of years used to determine if economic environment is highly inflationary				3 years
Foreign currency exchange rate								57
Maximum \| Subsidiary \| Argentina
Foreign Currency Translation
Operating income of subsidiaries as percent of consolidated amount high end of range							0.50%
Balance of the Company's overall net monetary assets valued functional currency								$ 430