Fair Value Measurements (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Reconciliation of items measured at fair value on a recurring basis that used significant unobservable inputs (Level 3)
Balance at the beginning of the period	$ 7	$ 5	$ 1
Total gains or losses included in other comprehensive income	(3)	2	6
Purchases, issuances, and settlements			(2)
Balance at the end of the period	4	7	5
Components of Comprehensive Income (Loss) Attributable to 3M
Additional losses included in earnings due to reclassifications from other comprehensive income for securities sold during the period ended December 31			$ (2)