Supplemental Equity and Comprehensive Income Information - AOCI rf (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
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	10,977
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)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	47	125
Amounts reclassified out	185	101
Total other comprehensive income (loss), before tax	232	226
Tax effect	(9)	70
Total other comprehensive income (loss), net of tax	223	296
Stockholders' Equity Attributable to 3M, Ending Balance	(6,803)	(6,949)
Cumulative Translation Adjustment
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(1,638)	(2,008)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	129	226
Total other comprehensive income (loss), before tax	129	226
Tax effect	39	63
Total other comprehensive income (loss), net of tax	168	289
Stockholders' Equity Attributable to 3M, Ending Balance	(1,470)	(1,719)
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)
Other comprehensive income (loss), before tax:
Amounts reclassified out	151	119
Total other comprehensive income (loss), before tax	151	119
Tax effect	(35)	(36)
Total other comprehensive income (loss), net of tax	116	83
Stockholders' Equity Attributable to 3M, Ending Balance	(5,160)	(5,245)
Cash flow hedging instruments gains (losses)
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(112)	91
Other comprehensive income (loss), before tax:
Amounts before reclassifications	(82)	(101)
Amounts reclassified out	34	(18)
Total other comprehensive income (loss), before tax	(48)	(119)
Tax effect	(13)	43
Total other comprehensive income (loss), net of tax	(61)	(76)
Stockholders' Equity Attributable to 3M, Ending Balance	$ (173)	$ 15