Derivatives - Currency Effects (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2015
Foreign Currency [Abstract]
Year On Year Currency Effect Gain (Loss) Impact On Pre tax Income	$ (95)	$ (295)
Year on Year Derivative and Other Transaction Gain (Loss) Impact on Pre tax Income	$ 70	$ 150

The year-on-year currency effects, including hedging impacts, on pre-tax net income attributable to 3M. This estimate includes the effect of translating profits from local currencies into U.S. dollars; the impact of currency fluctuations on the transfer of goods between 3M operations in the United States and abroad; and transaction gains and losses, including derivative instruments designed to reduce foreign currency exchange rate risks.

No definition available.

Name:	mmm_YearOnYearCurrencyEffectsImpactOnNetIncome
Namespace Prefix:	mmm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration