Supplemental Equity and Comprehensive Income Information - AOCI rf (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	$ 11,563
Other comprehensive income (loss), before tax:
Stockholders' Equity Attributable to 3M, Ending Balance	9,796	$ 11,563
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(7,026)	(7,245)	$ (6,359)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	(226)	(820)	(1,309)
Amounts reclassified out	702	476	312
Total other comprehensive income (loss), before tax	476	(344)	(997)
Tax effect	(317)	563	111
Total other comprehensive income (loss), net of tax	159	219	(886)
Transfer of ownership involving non-wholly owned subsidiaries	1
Stockholders' Equity Attributable to 3M, Ending Balance	(6,866)	(7,026)	(7,245)
Cumulative Translation Adjustment
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(1,638)	(2,008)	(1,679)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	(414)	91	(244)
Total other comprehensive income (loss), before tax	(414)	91	(244)
Tax effect	(47)	279	(85)
Total other comprehensive income (loss), net of tax	(461)	370	(329)
Transfer of ownership involving non-wholly owned subsidiaries	1
Stockholders' Equity Attributable to 3M, Ending Balance	(2,098)	(1,638)	(2,008)
Gains (losses) associated with defined benefit pension and postretirement plans amortization
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(5,276)	(5,328)	(4,804)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	55	(600)	(1,122)
Amounts reclassified out	606	483	421
Total other comprehensive income (loss), before tax	661	(117)	(701)
Tax effect	(217)	169	177
Total other comprehensive income (loss), net of tax	444	52	(524)
Stockholders' Equity Attributable to 3M, Ending Balance	(4,832)	(5,276)	(5,328)
Cash flow hedging instruments gains (losses)
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(112)	91	124
Other comprehensive income (loss), before tax:
Amounts before reclassifications	133	(311)	57
Amounts reclassified out	96	(7)	(109)
Total other comprehensive income (loss), before tax	229	(318)	(52)
Tax effect	(53)	115	19
Total other comprehensive income (loss), net of tax	176	(203)	(33)
Stockholders' Equity Attributable to 3M, Ending Balance	$ 64	$ (112)	$ 91