Supplemental Equity and Comprehensive Income Information - AOCI rf (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	$ 10,063
Other comprehensive income (loss), before tax:
Stockholders' Equity Attributable to 3M, Ending Balance	10,147
Cumulative Translation Adjustment
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(1,899)	$ (2,098)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	(439)	103
Total other comprehensive income (loss), before tax	(439)	103
Tax effect	(2)	(26)
Total other comprehensive income (loss), net of tax	(441)	77
Stockholders' Equity Attributable to 3M, Ending Balance	(2,340)	(2,034)
Cumulative Translation Adjustment | ASU 2018-02 Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income
AOCI Attributable to 3M, Net of Tax Roll Forward
Impact of ASUs		(13)
Defined Pension and Postretirement Plans Adjustment
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(6,209)	(4,832)
Other comprehensive income (loss), before tax:
Amounts reclassified out	164	104
Total other comprehensive income (loss), before tax	164	104
Tax effect	(45)	(20)
Total other comprehensive income (loss), net of tax	119	84
Stockholders' Equity Attributable to 3M, Ending Balance	(6,090)	(5,565)
Defined Pension and Postretirement Plans Adjustment | ASU 2018-02 Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income
AOCI Attributable to 3M, Net of Tax Roll Forward
Impact of ASUs		(817)
Cash Flow Hedging Instruments, Unrealized Gain (Loss)
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(31)	64
Other comprehensive income (loss), before tax:
Amounts before reclassifications	77	13
Amounts reclassified out	(16)	(7)
Total other comprehensive income (loss), before tax	61	6
Tax effect	(14)
Total other comprehensive income (loss), net of tax	47	6
Stockholders' Equity Attributable to 3M, Ending Balance	16	47
Cash Flow Hedging Instruments, Unrealized Gain (Loss) | ASU 2018-02 Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income
AOCI Attributable to 3M, Net of Tax Roll Forward
Impact of ASUs		(23)
Total Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(8,139)	(6,866)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	(362)	116
Amounts reclassified out	148	97
Total other comprehensive income (loss), before tax	(214)	213
Tax effect	(61)	(46)
Total other comprehensive income (loss), net of tax	(275)	167
Stockholders' Equity Attributable to 3M, Ending Balance	$ (8,414)	(7,552)
Total Accumulated Other Comprehensive Income (Loss) | ASU 2018-02 Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income
AOCI Attributable to 3M, Net of Tax Roll Forward
Impact of ASUs		$ (853)