Pension plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Pension Cost (Reversal of Cost)	$ 36,700,000	$ 45,000,000	$ 32,100,000
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%
Defined Contribution Plan Employer Matching Contribution	1.00
Defined Contribution Plan Employee Contribution	$ 1.00
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	7.00%	8.00%
Settlement loss (gain)		$ 10,600,000	$ 6,100,000
Plan settlements		41,600,000	26,300,000
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period	$ 7,600,000	7,400,000	7,600,000
Interest cost on benefit obligation	26,800,000	30,200,000	32,700,000
Expected return on plan assets	(43,200,000)	(48,300,000)	(51,400,000)
Settlement loss (gain)	0	10,600,000
Curtailment gain	(200,000)	(300,000)	0
Amortization of prior service cost	900,000	900,000	800,000
Recognized actuarial net (gain) or loss	16,700,000	14,100,000	14,600,000
Net periodic benefit (income) cost	8,600,000	14,600,000	10,400,000
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement loss (gain)			5,800,000
Defined Benefit Plan, Benefit Obligation, Benefits Paid			18,100,000
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	200,000
Interest cost on benefit obligation	100,000	200,000	200,000
Defined Benefit Plan, Benefit Obligation, Benefits Paid	800,000	900,000
Amortization of prior service cost	(300,000)	(300,000)	(300,000)
Recognized actuarial net (gain) or loss	(1,100,000)	(800,000)	(700,000)
Net periodic benefit (income) cost	(1,300,000)	(900,000)	(800,000)
Defined Contribution Plans 401K Savings Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution benefits plans	25,100,000	28,400,000	10,600,000
Bemis Investment Profit Sharing Plan and Other Defined Contribution Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution benefits plans	3,000,000	2,000,000	$ 11,100,000
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	40,300,000
Service cost - benefits earned during the period	4,000,000	3,800,000
Interest cost on benefit obligation	25,000,000	28,400,000
Defined Benefit Plan, Benefit Obligation, Benefits Paid	37,700,000	79,600,000
Plan settlements	0	0
Plan curtailments	$ 0	$ 0