Supplemental Equity and Comprehensive Income Information - AOCI rf (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance			$ 10,298
Other comprehensive income (loss), before tax:
Stockholders' Equity Attributable to 3M, Ending Balance	$ 12,146		12,146
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(6,989)	$ (6,184)	(7,245)	$ (6,359)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	(109)	(52)	(225)	(69)
Amounts reclassified out	121	79	336	203
Total other comprehensive income (loss), before tax	12	27	111	134
Tax effect	64	11	221	79
Total other comprehensive income (loss), net of tax	76	38	332	213
Stockholders' Equity Attributable to 3M, Ending Balance	(6,913)	(6,146)	(6,913)	(6,146)
Cumulative Translation Adjustment
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(1,786)	(1,503)	(2,008)	(1,679)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	(29)	(8)	30	111
Total other comprehensive income (loss), before tax	(29)	(8)	30	111
Tax effect	74	24	237	81
Total other comprehensive income (loss), net of tax	45	16	267	192
Stockholders' Equity Attributable to 3M, Ending Balance	(1,741)	(1,487)	(1,741)	(1,487)
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	(5,167)	(4,668)	(5,328)	(4,804)
Other comprehensive income (loss), before tax:
Amounts reclassified out	119	103	357	307
Total other comprehensive income (loss), before tax	119	103	357	307
Tax effect	(39)	(36)	(116)	(104)
Total other comprehensive income (loss), net of tax	80	67	241	203
Stockholders' Equity Attributable to 3M, Ending Balance	(5,087)	(4,601)	(5,087)	(4,601)
Cash flow hedging instruments gains (losses)
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(36)	(13)	91	124
Other comprehensive income (loss), before tax:
Amounts before reclassifications	(80)	(44)	(255)	(180)
Amounts reclassified out	2	(24)	(21)	(104)
Total other comprehensive income (loss), before tax	(78)	(68)	(276)	(284)
Tax effect	29	23	100	102
Total other comprehensive income (loss), net of tax	(49)	(45)	(176)	(182)
Stockholders' Equity Attributable to 3M, Ending Balance	$ (85)	$ (58)	$ (85)	$ (58)