Supplemental Equity and Comprehensive Income Information (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Components of Comprehensive Income (Loss) Attributable to 3M
Net income attributable to 3M	$ 954	$ 1,088	$ 1,160	$ 1,081	$ 928	$ 1,106	$ 1,121	$ 930	$ 4,283	$ 4,085	$ 3,193
Cumulative translation									(253)	213	288
Tax effect									(7)	(8)	(2)
Cumulative translation - net of tax									(260)	205	286
Defined benefit pension and postretirement plans adjustment									(1,977)	(68)	(442)
Tax effect									701	28	133
Defined benefit pension and postretirement plans adjustment - net of tax									(1,276)	(40)	(309)
Debt and equity securities, unrealized gain (loss)										5	17
Tax effect										(2)	(7)
Debt and equity securities, unrealized gain (loss) - net of tax										3	10
Cash flow hedging instruments, unrealized gain (loss)									84	6	(130)
Tax effect									(30)	(2)	50
Cash flow hedging instruments, unrealized gain (loss) - net of tax									54	4	(80)
Total Comprehensive income (loss) attributable to 3M									2,801	4,257	3,100
Reclassification to earnings from accumulated other comprehensive income including noncontrolling interest that related to pension and postretirement expense in the income statement, before tax									475	306	141
Reclassification to earnings from accumulated other comprehensive income including noncontrolling interest that related to pension and postretirement expense in the income statement, after tax									307	197	92
Reclassification to earnings from accumulated other comprehensive income to loss on debt and equity securities in the income statement, before tax									10
Reclassification to earnings from accumulated other comprehensive income attributable to 3M to loss on debt and equity securities in the income statement, after tax									6
Additional losses included in earnings due to reclassifications from other comprehensive income for securities sold during the period ended December 31											$ (2)