Supplemental Equity and Comprehensive Income Information (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Components of Comprehensive Income (Loss) Attributable to 3M
Net income attributable to 3M	$ 991	$ 1,161	$ 1,167	$ 1,125	$ 954	$ 1,088	$ 1,160	$ 1,081	$ 4,444	$ 4,283	$ 4,085
Cumulative translation									133	(253)	213
Tax effect									(17)	(7)	(8)
Cumulative translation - net of tax									116	(260)	205
Defined benefit pension and postretirement plans adjustment									411	(1,977)	(68)
Tax effect									(211)	701	28
Defined benefit pension and postretirement plans adjustment - net of tax									200	(1,276)	(40)
Debt and equity securities, unrealized gain (loss)									6	0	5
Tax effect									(2)	0	(2)
Debt and equity securities, unrealized gain (loss) - net of tax									4	0	3
Cash flow hedging instruments, unrealized gain (loss)									(69)	84	6
Tax effect									24	(30)	(2)
Cash flow hedging instruments, unrealized gain (loss) - net of tax									(45)	54	4
Comprehensive income (loss) attributable to 3M									4,719	2,801	4,257
Reclassification to earnings from accumulated other comprehensive income including noncontrolling interest that related to pension and postretirement expense in the income statement, before tax									615	475	306
Reclassification to earnings from accumulated other comprehensive income including noncontrolling interest that related to pension and postretirement expense in the income statement, after tax									396	307	197
Reclassification to earnings from accumulated other comprehensive income to gain (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 gain (loss) on debt and equity securities in the income statement, after tax										$ (6)