Supplemental Equity and Comprehensive Income Information (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Components of Comprehensive Income (Loss) Attributable to 3M
Net income attributable to 3M	$ 1,167	$ 1,160	$ 2,292	$ 2,241
Cumulative translation	(324)	205	(169)	426
Tax effect	(22)	20	(22)	47
Cumulative translation - net of tax	(346)	225	(191)	473
Defined benefit pension and postretirement plans adjustment	154	119	307	238
Tax effect	(56)	(66)	(112)	(109)
Defined benefit pension and postretirement plans adjustment - net of tax	98	53	195	129
Debt and equity securities, unrealized gain (loss)	(3)	(3)	2	(5)
Tax effect	1	1	(1)	2
Debt and equity securities, unrealized gain (loss) - net of tax	(2)	(2)	1	(3)
Cash flow hedging instruments, unrealized gain (loss)	37	1	13	(26)
Tax effect	(14)	(1)	(5)	9
Cash flow hedging instruments, unrealized gain (loss) - net of tax	23	0	8	(17)
Comprehensive income (loss) attributable to 3M	940	1,436	2,305	2,823
Reclassification to earnings from accumulated other comprehensive income including noncontrolling interest that related to pension and postretirement expense in the income statement, before tax	154	119	307	238
Reclassification to earnings from accumulated other comprehensive income including noncontrolling interest that related to pension and postretirement expense in the income statement, after tax	98	54	195	130
Reclassification to earnings from accumulated other comprehensive income to gain (loss) on debt and equity securities in the income statement, before tax		2	(1)	2
Reclassification to earnings from accumulated other comprehensive income to gain (loss) on debt and equity securities in the income statement, after tax		$ 1	$ (1)	$ 1