Pension and Postretirement Benefit Plans - Narrative (Details)	1 Months Ended	3 Months Ended				9 Months Ended
	May 31, 2019 USD ($) person	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2020 USD ($)
Benefit Plan Information
Defined benefit pension and postretirement plans adjustment		$ (127,000,000)		$ (76,000,000)		$ (304,000,000)	$ (356,000,000)
International | Funded | United Kingdom Pension Plan
Benefit Plan Information
Defined benefit pension and postretirement plans adjustment			$ 80,000,000
Qualified and Non-qualified Pension Benefits | Funded
Benefit Plan Information
Company contributions year to date						119,000,000
Qualified and Non-qualified Pension Benefits | United States | Funded
Benefit Plan Information
Special termination benefits - number of additional years of pension service	1
Special termination benefits - number of additional years of age for certain benefit calculations	1
Special termination benefits - number of participants | person	800
Special termination benefits charge					$ 35,000,000
Postretirement Benefits | Funded
Benefit Plan Information
Company contributions year to date						3,000,000
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		$ (127,000,000)		$ (76,000,000)		$ (304,000,000)	$ (356,000,000)
Total Accumulated Other Comprehensive Income (Loss) | International | Funded | United Kingdom Pension Plan
Benefit Plan Information
Defined benefit pension and postretirement plans adjustment			$ 80,000,000
Total Accumulated Other Comprehensive Income (Loss) | Postretirement Benefits | Funded
Benefit Plan Information
Defined benefit pension and postretirement plans adjustment					$ 150,000,000
Forecast | Pension and Postretirement Benefit Plans | Funded | Maximum
Benefit Plan Information
Estimated pension and postretirement employer contributions in current fiscal year								$ 200,000,000