Earnings Per Share Computations (Details) (USD $) In Millions, except Per Share data, 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
Numerator
Net income attributable to Bemis Company, Inc. (in dollars)	$ 40.1	$ 47.4	$ 42.3	$ 44.0	$ 22.8	$ 55.9	$ 54.2	$ 51.2	$ 173.8	$ 184.1	$ 205.1
Income allocated to participating securities (in dollars)									(1.8)	(2.8)	(3.7)
Net income available to common shareholders (in dollars)									$ 172.0	$ 181.3	$ 201.4
Denominator
Basic weighted-average common shares outstanding									103.2	104.6	108.7
Dilutive shares									0.7	0.4	0.1
Weighted-average common and common equivalent shares outstanding - diluted									103.9	105.0	108.8
Per common share income
Basic earnings per share, net income	$ 0.38	$ 0.46	$ 0.41	$ 0.42	$ 0.22	$ 0.53	$ 0.51	$ 0.47	$ 1.67	$ 1.73	$ 1.85
Diluted earnings per share, net income	$ 0.38	$ 0.45	$ 0.40	$ 0.42	$ 0.22	$ 0.53	$ 0.51	$ 0.47	$ 1.66	$ 1.73	$ 1.85
Basic weighted-average common shares outstanding									103.2	104.6	108.7
Basic weighted-average common shares, outstanding and participating securities									104.3	106.2	110.7
Percentage allocated to common shareholders									98.90%	98.50%	98.20%
Antidilutive stock options and stock awards											1.2