Earnings Per Share Computations (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Numerator
Net income attributable to Bemis Company, Inc. (in dollars)	$ 47.4	$ 55.9	$ 133.7	$ 161.3
Income allocated to participating securities (in dollars)	(0.4)	(0.8)	(1.5)	(2.4)
Net income available to common shareholders (in dollars)	$ 47.0	$ 55.1	$ 132.2	$ 158.9
Denominator
Basic weighted-average common shares outstanding	103.3	103.3	103.2	105.2
Dilutive shares	0.6	0.5	0.7	0.4
Weighted-average common and common equivalent shares outstanding - diluted	103.9	103.8	103.9	105.6
Per common share income
Basic (in dollars per share)	$ 0.46	$ 0.53	$ 1.28	$ 1.51
Diluted (in dollars per share)	$ 0.45	$ 0.53	$ 1.27	$ 1.51
Basic weighted-average common shares outstanding	103.3	103.3	103.2	105.2
Basic weighted-average common shares, outstanding and participating securities	104.2	104.8	104.3	106.8
Percentage allocated to common shareholders	99.10%	98.60%	98.90%	98.50%
Antidilutive stock options and stock awards		0.1