Supplemental Equity and Comprehensive Income Information - AOCI rf (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	$ 9,796
Other comprehensive income (loss), before tax:
Stockholders' Equity Attributable to 3M, Ending Balance	10,063	$ 9,796
Cumulative Translation Adjustment
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(2,098)	(1,638)	$ (2,008)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	102	(414)	91
Amounts reclassified out	142
Total other comprehensive income (loss), before tax	244	(414)	91
Tax effect	(32)	(47)	279
Total other comprehensive income (loss), net of tax	212	(461)	370
Transfer of ownership involving non-wholly owned subsidiaries		1
Stockholders' Equity Attributable to 3M, Ending Balance	(1,899)	(2,098)	(1,638)
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	(4,832)	(5,276)	(5,328)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	(1,227)	55	(604)
Amounts reclassified out	459	606	487
Total other comprehensive income (loss), before tax	(768)	661	(117)
Tax effect	208	(217)	169
Total other comprehensive income (loss), net of tax	(560)	444	52
Stockholders' Equity Attributable to 3M, Ending Balance	(6,209)	(4,832)	(5,276)
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)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	(26)
Amounts reclassified out	(70)
Total other comprehensive income (loss), before tax	(96)
Tax effect	24
Total other comprehensive income (loss), net of tax	(72)
Stockholders' Equity Attributable to 3M, Ending Balance	(31)
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)
Cash Flow Hedging Instruments, Unrealized Gain (Loss)
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	64	(112)	91
Other comprehensive income (loss), before tax:
Amounts before reclassifications		133	(311)
Amounts reclassified out		96	(7)
Total other comprehensive income (loss), before tax		229	(318)
Tax effect		(53)	115
Total other comprehensive income (loss), net of tax		176	(203)
Stockholders' Equity Attributable to 3M, Ending Balance		64	(112)
Total Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(6,866)	(7,026)	(7,245)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	(1,151)	(226)	(824)
Amounts reclassified out	531	702	480
Total other comprehensive income (loss), before tax	(620)	476	(344)
Tax effect	200	(317)	563
Total other comprehensive income (loss), net of tax	(420)	159	219
Transfer of ownership involving non-wholly owned subsidiaries		1
Stockholders' Equity Attributable to 3M, Ending Balance	(8,139)	$ (6,866)	$ (7,026)
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)			$ 900