Pension and Postretirement Benefit Plans - Narrative (Details)	1 Months Ended	3 Months Ended			12 Months Ended
	May 31, 2019 USD ($) person item	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Benefit Plan Information
Defined benefit pension and postretirement plans adjustment					$ (171,000,000)	$ 560,000,000	$ (444,000,000)
Qualified and Non-qualified Pension Benefits | Funded
Benefit Plan Information
Company contributions year to date					153,000,000	207,000,000
Qualified and Non-qualified Pension Benefits | United States | Funded
Benefit Plan Information
Company contributions year to date					61,000,000	101,000,000
Pension settlement charge			$ 32,000,000			35,000,000
Special termination benefits - number of additional years of pension service | item	1
Special termination benefits - number of additional years of age for certain benefit calculations | item	1
Special termination benefits - number of participants | person	800
Special termination benefits charge				$ 35,000,000
Qualified and Non-qualified Pension Benefits | International | Funded
Benefit Plan Information
Company contributions year to date					92,000,000	106,000,000
Pension settlement charge					(57,000,000)	1,000,000
Postretirement Benefits | Funded
Benefit Plan Information
Company contributions year to date					3,000,000	3,000,000
Pension settlement charge					(5,000,000)
Maximum life insurance and death benefit to be paid under the modified 3M Retiree Life Insurance Plan postretirement benefit	$ 8,000
Defined benefit pension and postretirement plans adjustment				$ 150,000,000
Total Accumulated Other Comprehensive Income (Loss)
Benefit Plan Information
Defined benefit pension and postretirement plans adjustment					$ (171,000,000)	$ 560,000,000	$ (444,000,000)
Total Accumulated Other Comprehensive Income (Loss) | International | Funded | United Kingdom Pension Plan
Benefit Plan Information
Defined benefit pension plan adjustment		$ 80,000,000
Other Assets | International | Funded | United Kingdom Pension Plan
Benefit Plan Information
Defined benefit pension plan adjustment		$ 80,000,000