Supplemental Equity and Comprehensive Income Information - Dividends and Transfer of Ownership Interest (Details) - $ / shares	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Dividends declared in current period (in dollars per share)	$ 1.47	$ 1.47	$ 1.47	$ 1.47	$ 1.44	$ 1.44	$ 1.44	$ 1.44	$ 1.36	$ 1.36	$ 1.36	$ 1.36	$ 5.88	$ 5.76	$ 5.44
3M India Limited
3M's ownership (as a percent)									75.00%						75.00%