Pension plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Pension Expense	$ 37,200,000	$ 53,200,000	$ 68,700,000
Employer matching contribution on each pre-tax dollar for the first two percent of participant's contribution		0.50
Defined Contribution Plan, Participants Contribution for First Two Percentage		1.00
Defined Contribution Plan, Employer Matching Contribution on Pretax Dollar for Next Six Percentage of Participants Contribution		0.25
Defined Contribution Plan, Participants Contribution for Next Six Percentage		1.00
Defined Contribution Plan, Employer Matching Contribution on Pre-tax Dollar for First Four Percentage of Participants Contribution	0.50
Employee contribution for the first four percent of the plan	1.00
Employer's matching contribution on each pre-tax dollar for the next four percent of participant's contribution	0.25
Participant's contribution for the next four percent to the plan	1.00
Next percentage of participant contributions eligible for employer contribution match towards defined contribution plan	4.00%	6.00%
Amount contributed to defined benefit multiemployear plans	700,000	1,000,000	1,300,000
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period	7,500,000	14,000,000	14,700,000
Interest cost on benefit obligation	34,000,000	32,500,000	33,700,000
Expected return on plan assets	(47,900,000)	(48,100,000)	(43,500,000)
Settlement loss (gain)	1,800,000	400,000	12,700,000
Curtailment gain	600,000	(400,000)	0
Amortization of unrecognized transition obligation	200,000	200,000	200,000
Amortization of prior service cost	1,400,000	1,800,000	1,500,000
Recognized actuarial net (gain) or loss	11,800,000	23,900,000	28,500,000
Net periodic benefit (income) cost	9,400,000	24,300,000	47,800,000
U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period	4,900,000	11,200,000
Interest cost on benefit obligation	30,700,000	29,500,000
Plan curtailments	(500,000)	(32,600,000)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period	100,000	300,000	300,000
Interest cost on benefit obligation	300,000	400,000	400,000
Curtailment gain	(3,000,000)
Amortization of prior service cost	(200,000)	(600,000)	(600,000)
Recognized actuarial net (gain) or loss	(300,000)	(300,000)	(300,000)
Net periodic benefit (income) cost	(3,700,000)	(200,000)	(200,000)
Plan curtailments	(3,600,000)	0	0
Defined Contribution Plans 401K Savings Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution benefits plans	10,600,000	9,000,000	8,900,000
Bemis Investment Profit Sharing Plan and Other Defined Contribution Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution benefits plans	$ 16,500,000	$ 18,900,000	$ 10,700,000