Significant Accounting Policies - Accounts receivable and Allowances (Details)	12 Months Ended
Dec. 31, 2020
Accounts receivable and allowance
Typical origination term for long-term customer receivables	5 years

The typical origination term for long-term customer receivables.

No definition available.

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